Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast – March 26 to April 1, 2012

Supernova in M95 - Credit: Larry McNish - RASC

Greetings, fellow SkyWatchers! Have you been following the supernova in M95 (R.A. = 10 43 53.76, Decl. = +11 40 17.9)? Who would have ever believed Mars could be considered “light pollution”? Take advantage of darker skies and catch it now! It’s another planetary showdown as the week begins with Jupiter, Venus, the Moon and the Pleiades lighting up the western twilight sky. Right now is an awesome time to study lunar features and to go asteroid hunting! Get out those telescopes and binoculars and I’ll meet you in the back yard…

Monday, March 26 – Need a smile? Then be outside after sunset to check out the awesome solar system show! How often do you see something as cool as the crescent Moon being accompanied by a bright planet like Venus? Or to have another bright planet like Jupiter so nearby? Keep looking, because you can spot the Pleiades just a bit further east. Be sure to point out to your family and friends what a great unaided eye observation can be like!

Tonight the Moon provides an opportunity to view to a very changeable and eventually bright feature on the lunar surface – Proclus. At 28 km in diameter and 2400 meters deep, crater Proclus will appear on the terminator to the west of Mare Crisium’s mountainous border. Depending on your viewing time, it will seem to be about two-thirds shadowed, but the remainder of the crater will shine brilliantly. Proclus has an unusually high albedo, or surface reflectivity, of about 16%. This is uncommon for most lunar features. Watch this area over the next few nights as two rays from the crater widen and lengthen, extending approximately 320 kilometers north and south.

While you’re out, this would also be a good time to have a look at Epsilon Canis Majoris – a great double star. While its companion is quite disparate at roughly magnitude 8, the pair can be easily separated with a small telescope.

Tuesday, March 27 – If you haven’t collected this Lunar Club Challenge crater, tonight will be the perfect opportunity to find the lunar crater named for Joseph Fraunhofer. Return again to the now shallow appearing crater Furnerius. Can you spot the ring at its southern edge? This is crater Fraunhofer – a challenge under these lighting conditions.

Have you noticed the dynamic duo? If not, then you owe it to yourself to take a look at the very close pairing of Spica and Saturn. It’s not often that you can spot a lot of color contrast between celestial objects without optical aid, but blue/white Alpha Virginis and creamy yellow Saturn should be quite noticeable. Have fun!

Speaking of pairs, why not revisit the “Twin Stars” – Castor and Pollux? Separated by not much more than 3 arc seconds, 2.0 magnitude Castor A has a bright sibling – 2.8 magnitude Castor B. The pair is actually a true binary with an orbital period of roughly 500 years. The Castor system contains four lesser members – each main star is a spectroscopic binary. Without Fraunhofer’s discovery of spectra, we would have never known.

Wednesday, March 28 – Born today in 1749, Pierre LaPlace was the mathematician who invented the metric system and the nebular hypothesis for the origin of the solar system. Also born on this day in 1693 was James Bradley, an excellent astrometrist who discovered the aberration of starlight (1729) and the nutation of the Earth. And, in 1802, Heinrich W. Olbers discovered the second asteroid, Pallas, in the constellation Virgo while making observations of the position of Ceres, which had only been discovered fifteen months earlier. Five years later on this same date in 1807, Vesta – the brightest asteroid – was discovered by Olbers in Virgo, making it the fourth such object found.

So, are you ready to go asteroid hunting? To capture asteroid Pallas, you’re going to have to stay up late or get up early, because it’s located right on the ecliptic just west of the circlet of Pisces and running ahead of the rising Sun. Its position will be roughly RA 23h 1m 37s – Dec 11°34’44”. But it does have one thing in its favor – it should be brighter than magnitude 5, so it will be an easy binocular object! Now for Ceres… At close to magnitude 3, it’s so bright you could spot it without optical aid! Tonight it will be visible just after the Sun sets about a handspan southwest of Saturn at roughly RA 2h 18m 43s – Dec 5°49’38”. It certainly makes a pretty picture with the Moon so nearby, too! Last, but not least, is Vesta. Also super-bright, and probably close to magnitude 4, you’ll find Olbers study scooting along the eastern edge of the asterism that denotes the constellation of Capricornus. Its position is roughly RA 21h 39m 21s – Dec 20°35’25”. Remember that time plays an important role in an asteroid’s exact position, and so does your observing location. Be sure to check the resources for planetarium programs or on-line generators that will give you specific information… and have fun!

Tonight’s outstanding lunar features are two craters that you simply can’t miss – Aristotle and Eudoxus. Located to the north, this pair will be highly prominent in binoculars as well as telescopes. The northernmost – Aristotle – was named for the great philosopher and has an expanse of 87 kilometers. Its deep, rugged walls show a wealth of detail at high power, including two small interior peaks. Companion crater Eudoxus, to the south, spans 67 kilometers and offers equally rugged detail.

Thursday, March 29 – Today celebrates the first flyby of Mercury by Mariner 10 in 1974. Mariner 10 was unique. It was the first spacecraft to use a gravity assist from the planet Venus to help it travel on to Mercury. Due to the geometry of its orbit, it was only able to study half the surface, but its 2800 photographs gave us the knowledge that Mercury looks similar to our Moon, has an iron-rich core, a magnetic field, and a very thin atmosphere. Right now Mercury is running ahead of the rising Sun just south of the circlet of Pisces.

Tonight the Moon provides a piece of scenic history as we take a more in-depth look at a previous study crater – Albategnius. This huge, hexagonal, mountain-walled plain appears near the terminator about one-third the way north of the south limb. This 135 kilometer wide crater is approximately 14,400 feet deep and its west wall casts a black shadow on the dark floor. Partially filled with lava after creation, Albategnius is a very ancient formation that later became home to several wall-breech craters, such as Klein, which can be seen telescopically on the southwest wall. Albategnius holds more than just the distinction of being a prominent crater tonight – it also holds a place in history. On May 9, 1962 Louis Smullin and Giorgio Fiocco of the Massachusetts Institute of Technology (MIT) aimed a ruby laser beam toward the Moon’s surface and Albategnius became the first lunar feature to reflect laser light from Earth.

On March 24, 1965 Ranger 9 took a “snapshot” of Albategnius from an altitude of approximately 2500 km. Ranger 9 was designed by NASA for one purpose – to achieve lunar impact trajectory and send back high-resolution photographs and video images of the lunar surface. Ranger 9 carried no other science packages. Its destiny was to simply take pictures right up to the moment of impact. They called it a “hard landing.”

Friday, March 30 – Tonight’s featured lunar crater is located on the south shore of Mare Imbrium right where the Apennine mountain range meets the terminator. At 58 kilometers in diameter and 12,300 feet deep, Eratosthenes is an unmistakable crater. Named after the ancient Greek mathematician, geographer and astronomer Eratosthenes, this splendid crater will display a bright west wall and a black interior hiding its massive crater capped central mountain 3570 meters high! Extending like a tail, an 80 kilometer mountain ridge angles away to its southwest. As beautiful as Eratosthenes appears tonight, it will fade away to almost total obscurity as the Moon approaches full. See if you can spot it again in five days.

Despite the bright waxing moon, we still have a chance to get a view of a sprinkling of faint stars high to the south at skydark. Located less than a finger-width west-northwest of Wezen (Delta Canis Majoris) – 6.5 magnitude NGC 2354 (Right Ascension: 7 : 14.3 – Declination: -25 : 44) is achievable in small scopes. Although richly populated, this open cluster lacks a bright core. This may challenge the eye to see it. Despite the moonlight, about a dozen stars should be visible in smaller scopes, but return on a moonless night to look for faint clumps and chaining among its 50 or so brightest members.

Before you hang up your eyepieces for the night, be sure to check out Mars. Today’s universal date marks Northern Summer, Southern Winter Solstice on the brilliant red planet. Do the polar caps look any different than they did a few weeks ago? How about surface features? Have you spotted any dust storms or changes? Keep watching, because it won’t be long before Mars is gone!

Saturday, March 31 – Tonight would be a terrific opportunity to study under-rated crater Bullialdus. Located close to the center of Mare Nubium, even binoculars can make out Bullialdus when near the terminator. If you’re scoping – power up – this one is fun! Very similar to Copernicus, Bullialdus’ has thick, terraced walls and a central peak. If you examine the area around it carefully, you can note it is a much newer crater than shallow Lubiniezsky to the north and almost non-existent Kies to the south. On Bullialdus’ southern flank, it’s easy to make out its A and B craterlets, as well as the interesting little Koenig to the southwest.

Today in 1966, Luna 10 was on its way to the Moon. The unmanned, battery powered Luna 10 was a USSR triumph. Launched from an Earth orbiting platform, the probe became the first to successfully orbit another solar system body. During its 460 orbits, it recorded infrared emissions, gamma rays, and analyzed lunar composition. It monitored the Moon’s radiation conditions – measuring the belts and discovering what eventually would be referred to as “mascons” – mass concentrations below maria surfaces which magnetically affect orbiting bodies. Do you remember any areas we’ve studied so far that contain a mascon?

While the Moon will be nearly overpowering tonight, let’s take a look at a pair of orbiting bodies as we head for Kappa Puppis – a bright double of near equal magnitudes. This one is well suited to northern observers with small telescopes. For the southern observer, try your hand at Sigma Puppis. At magnitude 3, this bright orange star holds a wide separation from its white 8.5 magnitude companion. Sigma’s B star is a curiosity, because at a distance of 180 light-years it would be about the same brightness as our own Sun placed at that distance!

Sunday, April 1 – Today in 1960, the first weather satellite – Tiros 1 – was launched. While today we think of these types of satellites as commonplace, the Television InfraRed Observation Satellite was quite an achievement. Weighing in at 120 kilograms, it contained two cameras and magnetic tape recorders – along with an on-board battery supply and 9200 solar cells to keep them charged. While it only operated successfully for 78 days, for the first time ever we were able to see the face of the Earth’s changing weather.

Tonight we’ll have the opportunity to look for a lunar feature named for Urbain Leverrier. To find it, start with the C-shape of Sinus Iridum. Imagine that Iridum is a mirror focusing light – this will lead your eye to crater Helicon. The slightly smaller crater southeast of Helicon is Leverrier. Be sure to power up to capture the splendid north-south oriented ridge which flows lunar east.

Now check out the close triangulation of Regulus, Mars and Algieba. This splendid triangulation of stars and a planet are only separated by a few degrees and make for a splendid sight!

Until next week? Ask for the Moon… But keep on reaching for the stars!

Posted on by Tammy Plotner

Speca – An Intriguing Look Into The Beginning Of A Black Hole Jet

A unique galaxy, which holds clues to the evolution of galaxies billions of years ago, has now been discovered by an Indian-led international team of astronomers. The discovery, which will enable scientists to unearth new aspects about the formation of galaxies in the early universe, has been made using the Giant Meterwave Radio Telescope (GMRT) of the National Centre for Radio Astrophysics, Tata Institute of Fundamental Research (NCRA-TIFR). CREDIT: Hota et al., SDSS, NCRA-TIFR, NRAO/AUI/NSF.

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Its name is SPECA – a Spiral-host Episodic radio galaxy tracing Cluster Accretion. That’s certainly a mouthful of words for this unusual galaxy, but there’s a lot more going on here than just its name. “This is probably the most exotic galaxy with a black hole, ever seen. It is like a ‘missing-link’ between present day and past galaxies. It has the potential to teach us new lessons about how galaxies and clusters of galaxies formed in the early Universe,” said Ananda Hota, of the Academia Sinica Institute of Astronomy and Astrophysics (ASIAA), in Taiwan and who discovered this exotic galaxy.

Located about 1.7 billion light-years from Earth, Speca is a radio source that contains a central supermassive black hole. As we have learned, galaxies of this type produce relativistic “jets” which are responsible for being bright at the radio frequencies, but that’s not all they create. While radio galaxies are generally elliptical, Speca is a spiral – reason behind is really unclear. As the relativistic jets surge with time, they create lobes of sub-atomic material at the outer edges which fan out as the material slows down… and Speca is one of only two galaxies so far discovered to show this type of recurrent jet activity. Normally it occurs once – and rarely twice – but here it has happened three times! We are looking at a unique opportunity to unravel the mysteries of the beginning phase of a black hole jet.

“Both elliptical and spiral galaxies have black holes, but Speca and another galaxy have been seen to produce large jets. It is also one of only two galaxies to show that such activity occurred in three separate episodes.” explains Sandeep Sirothia of NCRA-TIFR. “The reason behind this on-off activity of the black hole to produce jets is unknown. Such activities have not been reported earlier in spiral galaxies, which makes this new galaxy unique. It will help us learn new theories or change existing ones. We are now following the object and trying to analyse the activities.”

Dr. Hota and an international team of scientists reached their first conclusions while studying combined data from the visible-light Sloan Digital Sky Survey (SDSS) and the FIRST survey done with the Very Large Array (VLA) radio telescope. Here they discovered an unusually high rate of star formation where there should be none and they then confirmed their findings with ultraviolet data from NASA’s GALEX space telescope. Then the team dug even deeper with radio information obtained from the NRAO VLA Sky Survey (NVSS). At several hundred million years old, these outer lobes should be beyond their reproductive years… Yet, that wasn’t all. GMRT images displayed yet another, tiny lobe located just outside the stars at the edge of Speca in plasma that is just a few million years old.

“We think these old, relic lobes have been ‘re-lighted’ by shock waves from rapidly-moving material falling into the cluster of galaxies as the cluster continues to accrete matter,” said Ananda. “All these phenomena combined in one galaxy make Speca and its neighbours a valuable laboratory for studying how galaxies and clusters evolved billions of years ago.”

As you watch the above galaxy merger simulation created by Tiziana Di Matteo, Volker Springel, and Lars Hernquist, you are taking part in a visualization of two galaxies combining which both have central supermassive black holes and the gas distribution only. As they merge, you time travel over two billion years where the brightest hues indicate density while color denotes temperature. Such explosive process for the loss of gas is needed to understand how two colliding star-forming spiral galaxies can create an elliptical galaxy… a galaxy left with no fuel for future star formation. Outflow from the supernovae and central monster blackholes are the prime drivers of this galaxy evolution.

“Similarly, superfast jets from black holes are supposed to remove a large fraction of gas from a galaxy and stop further star formation. If the galaxy is gas-rich in the central region, and as the jet direction changes with time, it can have an adverse effect on the star formation history of a galaxy. Speca may have once been part of such a scenario. Where multiple jets have kicked out spiral arms from the galaxy. To understand such a process Dr Hota’s team has recently investigated NGC 3801 which has very young jet in very early-phase of hitting the host galaxy. Dust/PAH, HI and CO emission shows an extremely warped gas disk. HST data clearly showa outflow of heated-gas. This gas loss, as visualised in the video, has possibly caused the decline of star formation. However, the biggest blow from the monster’s jets are about to give the knock-down punch the galaxy.

“It seems, we observe this galaxy at a rare stage of its evolutionary sequence where post-merger star formation has already declined and new powerful jet feedback is about to affect the gaseous star forming outer disk within the next 10 million years to further transform it into a red-and-dead early-type galaxy.” Dr. Hota says.

The causes behind why present day radio galaxies do not contain a young star forming disks are not clear. Speca and NGC 3801 are ideal laboratories to understand black hole galaxy co-evolution processes.

Original Research Paper: Caught in the act: A post-merger starforming early-type galaxy with AGN-jet feedback. For Further Reading: Various press releases and news on the discovery of Speca. This article has been changed slightly from its original publication to reflect more information from Dr. Hota.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast – March 19-25, 2012

NGC 2539 - Credit: Palomar Observatory Courtesy of Caltech

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Greetings, fellow SkyWatchers! The week starts off with new Moon and the perfect opportunity to do a Messier Marathon. The planets continue to dazzle as we not only celebrate the Vernal Equinox, but the March Geminid meteor shower as well! If that doesn’t get your pulsar racing – nothing will. It’s time to get out your binoculars and telescopes and meet me in the backyard!

Monday, March 19 – Right now the Moon is between the Earth and the Sun, and you know what that means…New Moon! Tonight we’ll start in northern Puppis and collect three more Herschel studies as we begin at Alpha Monoceros and drop about four fingerwidths southeast to 19 Puppis.

NGC 2539 (Right Ascension: 8 : 10.7 – Declination: -12 : 50) averages around 6th magnitude and is a great catch for binoculars as an elongated hazy patch with 19 Puppis on the south side. Telescopes will begin resolution on its 65 compressed members, as well as split 19 Puppis – a wide triple. Shift about 5 degrees southwest and you find NGC 2479 (Right Ascension: 7 : 55.1 – Declination: -17 : 43) directly between two finderscope stars. At magnitude 9.6 it is telescopic only and will show as a smallish area of faint stars at low power. Head another degree or so southeast and you’ll encounter NGC 2509 (Right Ascension: 8 : 00.7 – Declination: -19 : 04) – a fairly large collection of around 40 stars that can be spotted in binoculars and small telescopes.

Tuesday, March 20 – Today is Vernal Equinox, one of the two times of the year that day and night become equal in length. From this point forward, the days will become longer – and our astronomy nights shorter! To the ancients, this was a time a renewal and planting – led by the goddess Eostre. As legend has it, she saved a bird whose wings were frozen from the winter’s cold, turning it into a hare which could also lay eggs. What a way to usher in the northern spring!

With the Moon still out of the picture, let’s finish our study of the Herschel objects in Puppis. Only three remain, and we’ll begin by dropping south-southeast of Rho and center the finder on a small collection of stars to locate NGC 2489 (Right Ascension: 7 : 56.2 – Declination: -30 : 04). At magnitude 7, this bright collection is worthy of binoculars, but only the small patch of stars in the center is the cluster. Under aperture and magnification you’ll find it to be a loose collection of around two dozen stars formed in interesting chains.

The next are a north-south oriented pair around 4 degrees due east of NGC 2489. You’ll find the northernmost – NGC 2571 (Right Ascension: 8 : 18.9 – Declination: -29 : 44) – at the northeast corner of a small finderscope or binocular triangle of faint stars. At magnitude 7, it will show as a fairly bright hazy spot with a few stars beginning to resolve with around 30 mixed magnitude members revealed to aperture. Less than a degree south is NGC 2567 (Right Ascension: 8 : 18.6 – Declination: -30 : 38). At around a half magnitude less in brightness, this rich open cluster has around 50 members to offer the larger telescope, which are arranged in loops and chains.

Congratulations on completing these challenging objects!

Are you up for another challenge? Then test your ability to judge magnitude as Mars has now dimmed to approximately -1.0. Does it look slightly different in size and brightness than it did a week or so ago? Keep watching!

Wednesday, March 21 – Take your telescopes or binoculars out tonight to look just north of Xi Puppis for a celebration of starlight known as M93 (Right Ascension: 7 : 44.6 – Declination: -23 : 52). Discovered in March of 1781 by Charles Messier, this bright open cluster is a rich concentration of various magnitudes that will simply explode in sprays of stellar fireworks in the eyepiece of a large telescope. Spanning 18 light-years of space and residing more than 3400 light-years away, it contains not only blue giants, but lovely golds as well. Jewels in the night…

Thursday, March 22 – Today in 1799 Friedrich Argelander was born. He was a compiler of star catalogues, studied variable stars and created the first international astronomical organization.

Tonight let’s celebrate no Moon and have a look at an object from an alternative catalog that was written by Lacaille, and which is about two fingerwidths south of Eta Canis Majoris.

Also known as Collinder 140, Lacaille’s 1751 catalog II.2 “nebulous star cluster” is a real beauty for binoculars and very low power in telescopes. More than 50% larger than the Full Moon, it contains around 30 stars and may be as far as 1000 light-years away. When re-cataloged by Collinder in 1931, its age was determined to be around 22 million years. While Lacaille noted it as nebulous, he was using a 15mm aperture reflector, and it is doubtful that he was able to fully resolve this splendid object. For telescope users, be sure to look for easy double Dunlop 47 in the same field.

Now, kick back and enjoy a spring evening with two meteor showers. In the northern hemisphere, look for the Camelopardalids. They have no definite peak, and a screaming fall rate of only one per hour. While that’s not much, at least they are the slowest meteors – entering our atmosphere at speeds of only 7 kilometers per second!

Far more interesting to both hemispheres will be the March Geminids which peak tonight. They were first discovered and recorded in 1973 and then confirmed in 1975. With a much faster fall rate of about 40 per hour, these slower than normal meteors will be fun to watch! When you see a bright streak, trace it back to its point of origin. Did you see a Camelopardalid, or a March Geminid?

Friday, March 23 – Today in 1840, the first photograph of the Moon was taken. The daguerreotype was exposed by American astronomer and medical doctor J. W. Draper. Draper’s fascination with chemical responses to light also led him to another first – a photo of the Orion Nebula.

Our target for tonight is an object that’s better suited for southern declinations – NGC 2451 (Right Ascension: 7 : 45.4 – Declination: -37 : 58). As both a Caldwell object (Collinder 161) and a southern skies binocular challenge, this colorful 2.8 magnitude cluster was probably discovered by Hodierna. Consisting of about 40 stars, its age is believed to be around 36 million years. It is very close to us at a distance of only 850 light-years. Take the time to closely study this object – for it is believed that due to the thinness of the galactic disk in this region, we are seeing two clusters superimposed on each other.

With the Moon out of the picture early, why not get caught up in a galaxy cluster study – Abell 426. Located just 2 degrees east of Algol in Perseus, this group of 233 galaxies spread over a region of several degrees of sky is easy enough to find – but difficult to observe. Spotting Abell galaxies in Perseus can be tough in smaller instruments, but those with large aperture scopes will find it worthy of time and attention.

At magnitude 11.6, NGC 1275 (Right Ascension: 3 : 19.8 – Declination: +41 : 31) is the brightest of the group and lies physically near the core of the cluster. Glimpsed in scopes as small as 150 mm aperture, NGC 1275 is a strong radio source and an active site of rapid star formation. Images of the galaxy show a strange blend of a perfect spiral being shattered by mottled turbulence. For this reason NGC 1275 is thought to be two galaxies in collision. Depending on seeing conditions and aperture, galaxy cluster Abell 426 may reveal anywhere from 10 to 24 small galaxies as faint as magnitude 15. The core of the cluster is more than 200 million light-years away, so it’s an achievement to spot even a few!

Saturday, March 24 – Today is the birthday of Walter Baade. Born in 1893, Baade was the first to resolve the Andromeda galaxy’s individual stars using the Hooker telescope during World War II blackout times, and he also developed the concept of stellar populations. He was the first to realize that there were two types of Cepheid variables, thereby refining the cosmic distance scale. He is also well known for discovering an area towards our galactic center which is relatively free of dust, now known as “Baade’s Window.”

Just after sunset, you really need to take a look out your western window for a really beautiful bit of scenery. As the sky darkens, look for the very tender crescent Moon lit with “Earthshine”. Above it you will see bright Jupiter. Above that you will see blazing Venus. And, if that’s not enough, just a little higher will bring you to the Pleiades! What a great way to start a weekend evening!

With the Moon so near the horizon, we have only a short time to view its features. Tonight let’s start with a central feature – Langrenus – and continue further south for crater Vendelinus. Spanning 92 by 100 miles and dropping 14,700 feet below the lunar surface, Vendelinus displays a partially dark floor with a west wall crest catching the brilliant light of an early sunrise. Notice also that its northeast wall is broken by a younger crater – Lame. Head’s up! It’s an Astronomical League challenge.

Once the Moon has set, revisit M46 in Puppis – along with its mysterious planetary nebula NGC 2438. Follow up with a visit to neighboring open cluster M47 – two degrees west-northwest. M47 may actually seem quite familiar to you already. Did you possibly encounter it when originally looking for M46? If so, then it’s also possible that you met up with 6.7 magnitude open cluster NGC 2423 (Right Ascension: 7 : 37.1 – Declination: -13 : 52), about a degree northeast of M47 and even dimmer 7.9 magnitude NGC 2414 (Right Ascension: 7 : 33.3 – Declination: -15 : 27 ) as well. That’s four open clusters and a planetary nebula all within four square arc-minutes of sky. That makes this a cluster of clusters!

Let’s return to study M47. Observers with binoculars or using a finderscope will notice how much brighter, and fewer, the stars of M47 are when compared to M46. This 12 light-year diameter compact cluster is only 1600 light-years away. Even as close as it is, not more than 50 member stars have been identified. M47 has about one tenth the stellar population of larger, denser, and three times more distant, M46.

Of historical interest, M47 was “discovered” three times: first by Giovanni Batista Hodierna in the mid-17th century, then by Charles Messier some 17 years later, and finally by William Herschel 14 years after that. How is it possible that such a bright and well-placed cluster needed “re-discovery?” Hodierna’s book of observations didn’t surface until 1984, and Messier gave the cluster’s declination the wrong sign, making its identification an enigma to later observers – because no such cluster could be found where Messier said it was!

Sunday, March 25 – Today in 1655, Titan – Saturn’s largest satellite – was discovered by Christian Huygens. He also discovered Saturn’s ring system during this same year. 350 years later, the probe named for Huygens stunned the world as it reached Titan and sent back information on this distant world. How about if we visit Saturn? You’ll find the creamy yellow planet located about a fistwidth northwest of bright, white Spica! Even a small telescope will reveal Titan, but remember… it orbits well outside the ring plane, so don’t mistake it for a background star! While you’re there, look closely around the ring edges for the smaller moons. A 4.5” telescope can easily show you three of them. How about the shadow the rings on the planet’s surface? Or how about the shadow of the planet on the rings? Is the Cassini division visible? If you have a larger telescope, look for other ring divisions as well. All are part and parcel of viewing incredible Saturn!

If you missed yesterday evening’s scenic line-up, don’t despair. Just after the Sun sets tonight – and above the western horizon – you’ll find the young Moon very closely paired with Jupiter. Keep traveling eastward (up) and you’ll encounter Venus. Continue east and the next stop is M45. Watch in the days ahead as the Moon sweeps by, continuing to provide us with a show! Need more? Then check out Leo and Mars! You’ll find a great triangulation of Regulus to the west, Mars to the east and Algieba to the north. If you didn’t know better, you’d almost swear the Lion swallowed the red planet.

Tonight let’s return to our previous studies of the Moon and revisit a challenging crater. Further south than Vendelinus, look for another large, mountain-walled plain named Furnerius, located not too far from the terminator. Although it has no central peak, its walls have been broken numerous times by many smaller impacts. Look at a rather large one just north of central on the crater floor. If skies are stable, power up and search for a rima extending from the northern edge. Keep in mind as you observe that our own Earth has been pummeled just as badly as its satellite.

On this day in 1951, 21 cm wavelength radiation from atomic hydrogen in the Milky Way was first detected. 1420 MHz H I studies continue to form the basis of a major part of modern radio astronomy. If you would like to have a look at a source of radio waves known as a pulsar, then aim your binoculars slightly more than a fistwidth east of bright Procyon. The first two bright stars you encounter will belong to the constellation of Hydrus and you will find pulsar CP0 834 just above the northernmost – Delta.

Unitl next week? May all your journeys be at light speed!

Posted on by Amy Shira Teitel

How NASA Will Improve its Telescopes’ Vision

The zodiacal light captures from Earth. Credit: ESO.

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Most of us have experienced the frustration of pollution, fog, or clouds turning a night of stargazing into an exercise in frustration. Turns out, NASA has been dealing with the same problems since it started launching large telescopes. Even in orbit, telescopes can’t see too well through the dust that litters the inner Solar System. But a team of NASA scientists have come up with a way to lift astronomy out of this cosmic fog. 

Venus, Earth, and Mars all orbit within a dust cloud made by comets and occasional collisions between asteroids. This so-called zodiacal cloud is the Solar System’s most luminous feature after the Sun and can be up to a thousand times brighter than the objects astronomers are actually targeting. The light affects orbital observations the same way light from a full Moon affects ground based observations. The zodiacal cloud is so bright that it has interfered with every infrared, optical, and ultraviolet astronomical observation mission NASA has ever launched.

The components of the proposed EZE mission. Credit: NASA.

“To put it simply, it has never been night for space astronomers,” said Matthew Greenhouse, an astrophysicist at NASA’s Goddard Space Flight Center in Greenbelt, MD. Light from the cloud is greatest in the plane of Earth’s orbit, the same plane in which every space telescope operates.

So how is NASA planning to get away from the cloud? By tilting future telescopes’ orbits. This type of adjustment would let spacecraft spend a significant portion of each orbit above and below the thickest dust, giving it a clearer view of objects in space.

“Just by placing a space telescope on these inclined orbits, we can improve its sensitivity by a factor of two in the near-ultraviolet and by 13 times in the infrared,” Greenhouse explained. “That’s a breakthrough in science capability with absolutely no increase in the size of the telescope’s mirror.”

Greenhouse has teamed up with Scott Benson and the COllaborative Modeling and Parametric Assessment of Space Systems (COMPASS) study team, both at NASA’s Glenn Research Center in Cleveland, OH. They’re investigating missions to put a telescope in this type of angle plane — an extra-zodiacal orbit — using new developments in solar arrays, electric propulsion and lower-cost expendable launch vehicles.

They’ve developed a proof-of-concept mission called the Extra-Zodiacal Explorer (EZE), a 1,500-pound EX-class observatory. EZE would launch on a SpaceX Falcon 9 rocket. A powerful new solar-electric drive as its upper stage would direct the spacecraft on a gravity-assist manoeuver past Earth or Mars, a flyby that would redirect the mission into an orbit inclined by as much as 30 degrees to Earth’s.

A NEXT engine during a test fire. At the time the image was taken, in December 2009, the thruster had operated continuously for more than 25,000 hours; it has now run for more than 40,000 hours. Credit: NASA.

NASA’s Evolutionary Xenon Thruster (NEXT) engine is an improved type of ion drive. It operates by removing electrons from atoms of xenon gas and accelerating the charged ions through an electric field to create thrust. While these types of engine provide much less thrust at any given time than traditional chemical rockets, they are much more fuel efficient and can operate for years.

Two of these advanced engines, which get their power from onboard solar arrays, would be housed in the EZE upper stage. They would fire to send the spacecraft on the planetary flyby that would put it into an extra-zodiacal orbit. “We’ve run one NEXT thruster for over 40,000 hours in ground testing, more than twice the thruster operating lifetime needed to deliver the EZE spacecraft to its extra-zodiacal orbit,” Benson explained. “This is mature technology that will enable much more cost-effective space missions across both the astrophysics and planetary science disciplines.”

If this concept mission works, the team says, it will be the best performance from an observatory in the history of NASA’s Explorer program. It will also be a game changer. As Greenhouse explained, “it will make extra-zodiacal orbits available to any astronomer proposing to NASA’s Explorer program. This will enable unprecedented science capability for astrophysics Explorers.”

Source: NASA.

Posted on by Tammy Plotner

The Care And Feeding Of Teenage Galaxies… And By The Way, They Need Gas

Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA

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Got a teenager? Then you know the story. Go to look for your favorite bag of chips and they’re gone. You eat one portion of meat and they need three. If you like those cookies, then you better have a darn good place to stash them. And, while you’re at it, their car needs gas. Apparently there’s a reason for the word “universal”, because teenage galaxies aren’t much different. Thanks to some new studies done by ESO’s Very Large Telescope, astronomers have been able to take a much closer look at adolescent galaxies and their “feeding habits” during their evolution. Some 3 to 5 billion years after the Big Bang they were happiest when just provided with gas, but later on they developed a voracious appetite… for smaller galaxies!

Scientists have long been aware that early galaxy structures were much smaller than the grand spirals and hefty ellipticals which fill the present Universe. However, figuring out exactly how galaxies put on weight – and where the bulk supply comes from – has remained an enigma. Now an international group of astronomers have taken on more than a hundred hours of observations taken with the VLT to help determine how gas-rich galaxies developed.

“Two different ways of growing galaxies are competing: violent merging events when larger galaxies eat smaller ones, or a smoother and continuous flow of gas onto galaxies.” explains team leader, Thierry Contini (IRAP, Toulouse, France). “Both can lead to lots of new stars being created.”

The undertaking is is MASSIV – the Mass Assembly Survey with the VIsible imaging Multi-Object Spectrograph, a powerful camera and spectrograph on the VLT. It’s incredible equipment used to measure distance and properties of the surveyed galaxies Not only did the survey observe in the near infrared, but also employed a integral field spectrograph and adaptive optics to refine the images. This enables astronomers to map inner galaxy movements and content, as well as leaving room for some very surprising results.

“For me, the biggest surprise was the discovery of many galaxies with no rotation of their gas. Such galaxies are not observed in the nearby Universe. None of the current theories predict these objects,” says Benoît Epinat, another member of the team.

“We also didn’t expect that so many of the young galaxies in the survey would have heavier elements concentrated in their outer parts — this is the exact opposite of what we see in galaxies today,” adds Thierry Contini.

These results point towards a major change during the galactic “teenage years”. At some time during the young Universe state, smooth gas flow was a considerable building block – but mergers would later play a more important role.

“To understand how galaxies grew and evolved we need to look at them in the greatest possible detail. The SINFONI instrument on ESO’s VLT is one of the most powerful tools in the world to dissect young and distant galaxies. It plays the same role that a microscope does for a biologist,” adds Thierry Contini.

The team plans on continuing to study these galaxies with future instruments on the VLT as well as using ALMA to study the cold gas in these galaxies. However, their work with gas isn’t the only “station” on the block. In a separate study led by Kate Rubin (Max Planck Institute for Astronomy), the Keck I telescope on Mauna Kea, Hawaii, has been used to examine gas associated with a hundred galaxies at distances between 5 and 8 billion light-years – the older teens. They have found initial evidence of gas flowing back into distant galaxies that are actively forming new stars.

Images of the six galaxies with detected inflows taken with the Advanced Camera for Surveys on the Hubble Space Telescope. Most of these galaxies have a disk-like, spiral structure, similar to that of the Milky Way. Star formation activity occurring in small knots is evident in several of the galaxies' spiral arms. Because the spirals appear tilted in the images, Rubin et al. concluded that we are viewing them from the side, rather than face-on. This orientation meshes well with a scenario of 'galactic recycling' in which gas is blown out of a galaxy perpendicular to its disk, and then falls back in at different locations along the edge of the disk. Credit: K. Rubin, MPIA

Apparently, like a teenager with the munchies, matter finds its way into those galactic tummies. One feeding theory is an inflow from huge low-density gas reservoirs filling the intergalactic voids… another is huge cosmic matter cycle. While there is very little evidence to support either hypothesis, gases have been observed to flow away from some galaxies and may be moshed around by several different sources – such as supernovae events or peer pressure from gigantic stars.

“As this gas drifts away, it is pulled back by the galaxy’s gravity, and could re-enter the same galaxy in time scales of one to several billion years. This process might solve the mystery: the gas we find inside galaxies may only be about half of the raw material that ends up as fuel for star formation.” says Dr. Rubin. “Large amounts of gas are caught in transit, but will re-enter the galaxy in due time. Add up the galaxy’s gas and the gas currently undergoing cosmic recycling, and there is a sufficient amount of raw matter to account for the observed rates of star formation.”

It might very well be a case of cosmic recycling… but I’d feel safer hiding my cookies.

Original Story Sources: ESO News Release and MPIA Science News Release. For Further Reading: Research Paper 1, Research Paper 2, Research Paper 3 and Research Paper 4.

Posted on by Fraser Cain

Venus-Jupiter Conjunction, March 15th, 2012

The two conjunctions. Image credit: Stellarium
The two conjunctions. Image credit: Stellarium

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In case you’re the only person on Earth who hasn’t heard about it yet, Venus and Jupiter will be in conjunction on March 15th, 2012, passing within 3° of each other. The two planets have been getting closer and closer in the sky for the last month, and now it’s time to see them side-by-side. Venus is the higher, brighter object, and Jupiter is the lower dimmer one.

Of course, Venus and Jupiter aren’t actually close to one another in the sky. They’re really separated by millions of kilometres. But from our perspective here on Earth, we see the two objects closely lined up. That’s a conjunction.

On March 15th, 2012 at 10:37 UTC, Venus and Jupiter reach 3° distance from one another. That’s approximately 6 times the width of the full Moon.

And in case you’re wondering, the conjunction will be visible from everywhere on Earth: from Australia to Canada, from Japan to Chile. The two planets will brighten in the West shortly after sunset. Since Venus and Jupiter are two of the brightest objects, they’ll be visible even in the most light polluted cities.

As a special bonus, the planet Mars is also high and bright in the sky, visible as that bright red “star” further to the East. Mars recently reached its closest point to Earth, known as opposition. Mars won’t be this close and bright for two more years.

Venus/Jupiter/Moon conjunction 2012 Image credit: Fraser Cain
Venus/Jupiter/Moon conjunction 2012 Image credit: Fraser Cain

The sky show will continue, and on March 25th, 2012, the New Moon will join the pair again to create a triple conjunction. Another great photo opportunity. Here’s our photo gallery of images Universe Today readers sent in during the last Moon/Venus/Jupiter conjunction.

Although 3° sounds close, they can actually get much closer. In October 26, 2015, for example, the two planets will only be 1° apart. But this is one of the best conjunctions we’ll see for a few years because the two planets are so high in the sky after the Sun sets.

We’d love to see your pictures of the conjunction. Please email them to [email protected], and we’ll post them in a few days.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast – March 12-18, 2012

Venus & Jupiter above Backyard Observatory - Credit: John Chumack

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Greetings, fellow SkyWatchers! What an awesome display of planets! Please take the time to walk outdoors just after skydark – regardless of where you live – and enjoy the bright display of Venus and Jupiter! However, this isn’t the only planetary action going on this week… Mars and M96 pair up, as well as Uranus and the Moon. There’s even a Southern Hemisphere meteor shower to enjoy! Pretty exciting, huh? Join the party by getting out your binoculars or telescopes and meet me for more in the backyard…

Monday, March 12 – No. That’s not the “headlights” of a UFO on the western horizon tonight… It’s a very cool pairing of Venus and Jupiter! It’s not often you see the two visually brightest planets making a close visual pass at each other and tonight you’ll spot the inner planet to the south and the outer planet to the north. This would make a great photo opportunity! Why not consider adding something interesting to your picture like a scenic building, tree, or even a person? Watch in the days ahead as Jupiter appears to stay in the same spot at the same time, yet Venus will climb higher.

Tonight let’s return again to NGC 2362 and start at the cluster’s north-northeast corner to have a look at a single, unusual star – UW Canis Majoris. At magnitude 4.9, this super-giant spectroscopic binary is one of the most massive and luminous in our galaxy. Its two stars are separated by only 27 million kilometers (17 million miles) and revolve around each other at a frenzied pace – in less than four and a half days. This speed means the stars themselves are flattened and would appear to be almost egg-shaped. The primary itself is shedding material that’s being collected by the secondary star.

Now drop southwest of NGC 2362 for another open cluster – NGC 2354 (Right Ascension: 7 : 14.3 – Declination: -25 : 44). While at best this will appear as a small, hazy patch to binoculars, NGC 2354 is actually a rich galactic cluster containing around 60 metal-poor members. As aperture and magnification increase, the cluster shows two delightful circle-like structures of stars, similar to a figure 8. Be sure to make a note… You’ve captured another Herschel 400 object!

Tuesday, March 13 – On this day in 1781, Uranus was discovered by William Herschel. Also on this day, in 1855, Percival Lowell was born in Boston. Educated at Harvard, Lowell went on to found the observatory which bears his name in Flagstaff, Arizona, and spent a lifetime studying Mars. During the early morning hours, you can honor Lowell by seeing Mars yourself – it’s best viewed when as high a possible on the ecliptic. While there won’t be a great many details, think of how many strides have been made since Lowell’s time and how advanced our knowledge of Mars has become!

Tonight let’s hop about four fingerwidths east-northeast of Sirius. Look for 5th magnitude SAO 152641 to guide you to a faint patch of stars in binoculars and a superb cluster in a telescope – NGC 2360 (Right Ascension: 7 : 17.8 – Declination: -15 : 37). Comprised of around eighty 10th magnitude and fainter stars, this particular cluster will look like a handful of diamond dust scattered on the sky. Discovered by Caroline Herschel in 1783, this intermediate-aged galactic cluster is home to red giants and heavy in metal abundance. Mark your notes, because not only is this a Herschel object, but is known as Caldwell 58 as well!

Wednesday, March 14 – Today is the birthday of Albert Einstein. Born in 1879, Einstein was one of the finest minds of our times. He developed the theory of gravity in terms of spacetime curvature – dependent on the energy density. Winner of the 1921 Physics Nobel prize, Einstein’s work on the photoelectric effect is the basis of modern light detectors.

Tonight let’s hop about a fistwidth north of bright Eta Canis Majoris and have a look at a “double cluster” – NGC 2383 (Right Ascension: 7 : 24.8 – Declination: -20 : 56) and NGC 2384 (Right Ascension: 7 : 25.1 – Declination: -21 : 02). Just showing in binoculars as a faint patch, this pair will begin resolution with larger scopes. Studied photometrically, it would appear these fairly young clusters have contaminated each other by sharing stars – which has also occurred in some clusters located in the Magellanic Clouds. Enjoy this unusual collection of stars…

Thursday, March 15 – Today celebrates the birth of Nicolas Lacaille. Born in 1713, Lacaille’s measurements confirmed the Earth’s equatorial bulge. He also named fourteen southern constellations. To honor Lacaille tonight, let’s begin some explorations in a constellation he named – Puppis!

For SkyWatchers living in high northern latitudes, you’ll never see all of this constellation, but there will be some things for you to explore, as well as a great deal for our friends in the southern hemisphere. The first is a Herschel object that lies directly on the galactic equator around five degrees north-northwest of Xi.

NGC 2421 (Right Ascension: 7 :36.3 – Declination: -20 : 37) is a magnitude 8.3 open cluster that will look like an exquisitely tiny “Brocchi’s Cluster” in binoculars and begin good resolution of its 50 or so members to an intermediate telescope, in an arrowhead-shaped pattern. It’s bright, it’s fairly easy to find, and it’s a great open cluster to add to your challenge study lists!

If you’re looking for a curiosity, then look no further than Leo and Mars. Tonight the happy red planet is situated just to the east of Messier 96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49)! Enjoy celestial mechanics over the next few nights as Mars gently changes its position in relation with this distant galaxy… and gets much closer!

Friday, March 16 – On this day in 1926, Robert Goddard launched the first liquid-fuel rocket. But he was first noticed in 1907 when a cloud of smoke issued from a powder rocket fired in the basement of the physics building in Worcester Polytechnic Institute. Needless to say, the school took an interest in the work of this shy student. Thankfully they did not expel him, and thus began his lifetime of work in rocket science. Goddard was also the first to realize the full implications of rocketry for missiles and space flight, and his lifetime of work was dedicated to bringing this vision to realization. While most of what he did went unrecognized for many years, tonight we celebrate the name of Robert H. Goddard. This first flight may have gone only 12 meters, but forty years later on the date of his birth, Gemini 8 was launched, carrying Neil Armstrong and David Scott into orbit!

Let’s begin our observing evening with Mars. While you may have been keeping track of its position, did you know that it’s less than a degree away from a Messier object tonight? That’s right! You’ll find the dusty red planet just to the north of M96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49).

Tonight we’ll pick up a challenge cluster and a planetary nebula on the Herschel list by returning to NGC 2421 and hopping about a fingerwidth northeast for NGC 2432 (Right Ascension: 7 : 40.9 – Declination: -19 : 05). This small, loose open cluster is rather dim and contains around 20 or so faint members shaped like the letter B. About another degree northeast is NGC 2440 – an elongated, small 11th magnitude planetary nebula. Look for its central star to cause a brightening and up the magnifying power to reveal it.

While out, be on watch for the Corona-Australids meteor shower. While the fall rate is low – 5 to 7 per hour – our friends in the southern hemisphere might stand a chance with this one!

Saturday, March 17 – On this day in 1958, the first solar-powered spacecraft was launched. Named Vanguard 1, it was an engineering test satellite. From its orbital position, the data taken from its transmission helped to redefine the true shape of the Earth.

Tonight let’s return to Xi Puppis and head less than a fingerwidth east-northeast for Herschel study NGC 2482 (Right Ascension: 7 : 54.9 – Declination: -24 : 18). At magnitude 7, this small fuzzy spot in binoculars will resolve into around two dozen stars to the telescope. Look for the diagonal chain of stars along its edge.

Now let’s have a look at an open cluster easily located in northeastern Orion. This 5.9 magnitude scattered group of stars may have been first observed by Giovanni Batista Hodierna in the mid-17th century. While bright enough to have been a Messier object, William Herschel added it to his log of discoveries on October 15, 1784, as H VIII.24. Of the 30 known stars associated with this 3,600 light-year distant group, the brightest is 50 million years old. A half-dozen of the cluster’s very brightest members can be seen in small scopes at mid-range powers. Look for NGC 2169 (Right Ascension: 6 : 08.4 – Declination: +13 : 57) slightly less than a fist width north-northeast of Betelguese and slightly south of Xi and Nu Orionis.

Sunday, March 18 – Although you can’t see it with just your eyes, Uranus is less than a degree from the Moon this morning. For some areas this could be an occultation, so be sure to check IOTA information!

Today in 1965, the first ever spacewalk was performed by Alexei Leonov onboard the Soviet Voskhod spacecraft. The “walk” only lasted around 20 minutes and Alexei had problems in re-entering the spacecraft because his space suit had enlarged slightly. Imagine his fear as he had to let air leak out of his space suit in order to squeeze back inside. When they landed off target in the heavily forested Ural Mountains, the crew of two had to spend the night in the woods surrounded by wolves. It took over twenty-four hours before they were located and workers had to chop their way through the forest and recover them on skis. Brave men!

Tonight let’s honor them by studying a small area which contains not only three Herschel objects – but two Messiers as well – M46 and M47. You’ll find them less than a handspan east of Sirius and about a fistwidth north of Xi Puppis.

The brighter of the two clusters is M47 (Right Ascension: 7 : 36.6 – Declination: -14 : 30) and at 1600 light-years away, it’s a glorious object for binoculars. It is filled with mixed magnitude stars that resolve fully to aperture with the double Struve 1211 near its center. While M47 is in itself a Herschel object, look just slightly north (about a field of view) to pick up another cluster which borders it. At magnitude 6.7, NGC 2423 isn’t as grand, but it contains more than two dozen fairly compressed faint stars with a lovely golden binary at its center.

Now return to M47 and hop east to locate M46 (Right Ascension: 7 : 41.8 – Declination: -14 : 49). While this star cluster will appear to be fainter and more compressed in binoculars, you’ll notice one star seems brighter than the rest. Using a telescope, you’ll soon discover the reason. 300 million year old M47 contains a Herschel planetary nebula known as NGC 2438 in its northern portion. The cluster contains around 150 resolvable stars and may involve as many as 500. The bright planetary nebula was first noted by Sir William Herschel and then again by John. While it would appear to be a member of the cluster, the planetary nebula is just a little closer to us than the cluster. Be sure to mark your notes… There’s a lot there in just a little area!

Until next week? May all of your journeys be at light speed!

Many thanks to John Chumack for the inspiring image!

Posted on by Jason Major

The Most Astounding Fact About The Universe

In a 2008 interview by TIME magazine, astrophysicist Neil deGrasse Tyson was asked what he thought the “most astounding fact” about the Universe was. Never at a loss for words, the famed scientist gave his equally astounding answer. His response is in the video above, set to images and music by Max Schlickenmeyer.

It’s the best three minutes and thirty-three seconds you’ll spend all day.

Via io9.com and It’s Okay to be Smart.

Posted on by Tammy Plotner

Weekly SkyWatcher’s Forecast: March 5-11, 2012

Open Cluster Messier 50 - Credit: NOAO/AURA/NSF

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Greetings, fellow SkyWatchers! Our week begins with the dance of the planets and a gathering of asteroids. Keep watching as Mars makes its closest approach of the year – while Venus and Jupiter continue to get nearer. Celebrate the Full Worm Moon, interesting stars and beautful galaxies and clusters! Dust off those binoculars and telescopes and meet me in the backyard, because… Here’s what’s up!

Monday, March 5 – Today is the birthday of Gerardus Mercator, famed mapmaker, who started his life in 1512. Mercator’s time was a rough one for astronomy, but despite a prison sentence and the threat of torture and death for his “beliefs,” he went on to design a celestial globe in the year 1551.

Need a little celestial action of your own? Then be outside at twilight with a clear horizon to catch Mercury! joining the show with Venus and Jupiter. The swift inner planet will make a brief appearance on the western skyline just after the Sun dips below the horizon. To add to the fun, the planet Uranus is situated about 5 degrees to its southwest and asteroid Vesta is about 5 degrees south/southwest. More? Then know that asteroid Ceres is also here – just around 20 degrees to Mercury’s southeast. While the asteroids and Uranus really aren’t observable, it’s still fun to know they’re “hanging around” in the same small space!

Tonight we’ll ignore the Moon and use both Sirius and Beta Monocerotis as our guides to have a look at one fantastic galactic cluster for any optical aid – M50 (Right Ascension: 7 : 03.2 – Declination: -08 : 20). Hop about a fistwidth east-southeast of Beta, or northeast of Sirius…and be prepared!

Perhaps discovered as early as 1711 by G. D. Cassini, it was relocated by Messier in 1772 and confirmed by J. E. Bode in 1774. Containing perhaps as many as 200 members, this colorful old cluster resides almost 3000 light-years away. The light of the stars you are looking at tonight left this cluster at a time when iron was first being smelted and used in tools. The Mayan culture was just beginning to develop, while the Hebrews and Phoenicians were creating an alphabet. Do you wonder if it looked the same then as it does now? In binoculars you will see an almost heart-shaped collection of stars, while telescopes will begin to resolve out color and many fainter members – with a very notable red one in its midst. Enjoy this worthy cluster and make a note that you’ve captured another Messier object!

Now, point your telescope towards Mars! This universal date marks the closest approach of Mars and Earth (0.6737 AU = 100.78 million km). While it’s a far cry from being the much celebrated “size of the Moon”, Mars currently has an apparent diameter of 13.89″. This will make for some mighty fine observing, so be sure to check for a lot a great surface details!

Tuesday, March 6 – If you get a chance to see sunshine today, then celebrate the birthday of Joseph Fraunhofer, who was born in 1787. As a German scientist, Fraunhofer was truly a “trailblazer” in terms of modern astronomy. His field? Spectroscopy! After having served his apprenticeship as a lens and mirror maker, Fraunhofer went on to develop scientific instruments, specializing in applied optics. While designing the achromatic objective lens for the telescope, he was watching the spectrum of solar light passing through a thin slit and saw the dark lines which make up the “rainbow bar code.” Fraunhofer knew that some of these lines could be used as a wavelength standard so he began measuring. The most prominent of the lines he labeled with letters that are still in use. His skill in optics, mathematics and physics led Fraunhofer to design and build the very first diffraction grating which was capable of measuring the wavelengths of specific colors and dark lines in the solar spectrum. Did his telescope designs succeed? Of course! His work with the achromatic objective lens is the design still used in modern telescopes!

In 1986, the first of eight consecutive days of flybys began as VEGA 1 and Giotto became the very first spacecraft to reach Halley’s Comet. Tonight let’s just fly by the Moon and have a look at Theta Aurigae. 2.7 magnitude Theta is a four star system ranging in magnitudes from 2.7 to 10.7. The brightest companion – Theta B – is magnitude 7.2 and is separated from the primary by slightly more than 3 arc seconds. Remember that this is what is known as a “disparate double” and look for the two fainter members well away from the primary.

Wednesday, March 7 – Today the only child of William Herschel (the discoverer of Uranus) was born in 1792 – John Herschel. He became the first astronomer to thoroughly survey the southern hemisphere’s sky, and he was discoverer of photographic fixer. Also born on this day, but in 1837, was Henry Draper – the man who made the first photograph of a stellar spectrum.

Tonight the great Grimaldi, found in the central region of the Moon near the terminator is the best lunar feature for binoculars. If you would like to see how well you have mastered your telescopic skills, then let’s start there. About one Grimaldi length south, you’ll see a narrow black ellipse with a bright rim. This is Rocca. Go the same distance again (and a bit east) to spot a small, shallow crater with a dark floor. This is Cruger, and its lava-filled interior is very similar to another study – Billy. Now look between them. Can you see a couple of tiny dark markings? Believe it or not, this is called Mare Aestatis. It’s not even large enough to be considered a medium-sized crater, but is a mare!

Take the time tonight to have a look at Delta Monocerotis with binoculars. Although it is not a difficult double star, it is faint enough to require some optical aid. If you are using a telescope, hop to Epsilon. It’s a lovely yellow and blue system that’s perfect for small apertures.

Thursday, March 8 – On this day in 1977, the NASA airborne occultation observatory made a unique discovery – Uranus had rings!

Tonight we’ll play ring around the Full Moon. In many cultures, it is known as the “Worm Moon.” As ground temperatures begin to warm and produce a thaw in the northern hemisphere, earthworms return and encourage the return of robins. For the Indians of the far north, this was also considered the “Crow Moon.” The return of the black bird signaled the end of winter. Sometimes it has been called the “Crust Moon” because warmer temperatures melt existing snow during the day, leaving it to freeze at night. Perhaps you may have also heard it referred to as the “Sap Moon.” This marks the time of tapping maple trees to make syrup. To early American settlers, it was called the “Lenten Moon” and was considered to be the last full Moon of winter. For those of us in northern climes, let’s hope so!

Friday, March 9 – Today is the anniversary of the Sputnik 9 launch in 1966 which carried a dog named Chernushka (Blackie). Also today we recognize the birth of David Fabricius. Born in 1564, Fabricus was the discoverer of the first variable star – Mira. Tonight let’s visit with an unusual variable star as we look at Beta Canis Majoris – better known as Murzim.

Located about three fingerwidths west-southwest of Sirius, Beta is a member of a group of stars known as quasi-Cepheids – stars which have very short term and small brightness changes. First noted in 1928, Beta changes no more than .03 in magnitude, and its spectral lines will widen in cycles longer than those of its pulsations.

When you’ve had a look at Beta, hop another fingerwidth west-southwest for open cluster NGC 2204 (Right Ascension: 6 : 15.7 – Declination: -18 : 39). Chances are, this small collection of stars was discovered by Caroline Herschel in 1783, but it was added to William’s list. This challenging object is a tough call for even large binoculars and small telescopes, since only around a handful of its dim members can be resolved. To the larger scope, a small round concentration can be seen, making this Herschel study one of the more challenging. While it might not seem like it’s worth the trouble, this is one of the oldest of galactic clusters residing in the halo and has been a study for “blue straggler” stars.

Saturday, March 10 – Since this is a weekend night and we’ve a short time before Moonrise, why not break out the big telescope and do a little galaxy hopping in the region south of Beta Canis Majoris?

Our first mark will be NGC 2207 – a 12.3 magnitude pair of interacting galaxies. Located some 114 million light-years away, this pair is locked in a gravitational tug of war. The larger of the pair is NGC 2207 (Right Ascension: 6 : 16.4 – Declination: -21 : 22), and it is estimated the encounter began with the Milky Way-sized IC 2163 about 40 million years ago. Like the M81 and M82 pair, NGC 2207 will cannibalize the smaller galaxy – yet the true space between the stars is so far apart that actual collisions may never occur. While our eyes may never see as grandly as a photograph, a mid-sized telescope will make out the signature of two galactic cores with intertwining material. Enjoy this great pair!

Now shift further southeast for NGC 2223 (Right Ascension: 6 : 24.6 – Declination: -22 : 50). Slightly fainter and smaller than the previous pair, this round, low surface brightness galaxy shows a slightly brighter nucleus area and a small star caught on its southern edge. While it seems a bit more boring, it did have a supernova event as recently as 1993!

Sunday, March 11 – Tonight let’s return to Canis Major with binoculars and have a look at Omicron 1, the western-most star in the central Omicron pair. While this bright, colorful gathering of stars is not a true cluster, it is certainly an interesting group.

For larger binoculars and telescopes, hop on to Tau northeast of Delta and the open cluster NGC 2362 (Right Ascension: 7: 18.8 – Declination: -24 : 5). At a distance of about 4600 light-years, this rich little cluster contains about 40 members and is one of the youngest of all known star clusters. Many of the stars you can resolve have not even reached main sequence yet! Still gathering themselves together, it is estimated this stellar collection is less than a million years old. Its central star, Tau, is believed to be a true cluster member and one of the most luminous stars known. Put as much magnification on this one as skies will allow – it’s a beauty!

Until next week? Dreams really do come true when you keep on reaching for the stars!

If you enjoy this weekly observing column, then you’d love the fully illustrated The Night Sky Companion 2012. It’s available in both Kindle and soft cover formats!

Posted on by Nancy Atkinson

How to Avoid ‘Bad Astrophotography:’ Advice from Thierry Legault

A collection of different satellites...or are they? Credit: Thierry Legault

Take a look at the collection of images above. All are high resolution astrophotos of different artificial satellites, taken by renowned astrophotographer Thierry Legault, using one of his 10″ telescopes and a simple webcam. The images have been sharpened and enlarged so that it’s easy to see small structures on the satellites such as antennas or solar panels.

Like this one, which is surely the Soyuz, with solar panels on each side:

Could this object be a Soyuz spacecraft? Credit: Thierry Legault

These are pretty awesome images….

…except Thierry and I are not telling the truth.

These images are not of satellites, but are all pictures of the star Vega.

What you have just seen is an example of what Legault calls “Bad Astrophotography,” a phrase Legault uses in homage to Phil Plait and his Bad Astronomy blog. Basically, this means that because of image artifacts or over-processing you can be fooled – intentionally or unintentionally — into seeing something that is not really there.

“In any raw image there is noise and if you process this image too strongly, the noise appears and some processing can transform the noise into something that looks like detail – but it is not detail,” said Legault.

So just like the images that have been touted as the Bigfoot on Mars, or even blurry pictures of supposed UFOs, sometimes astrophotos can look like something they are not.

“Many people are not aware that an image is not reality — it is a transformation of reality,” Legault told Universe Today, “and any image that is taken under difficult conditions or close to the resolution limits of the telescope, the image is less and less reliable or reflects less and less the reality.”

Many things can cause problems in astrophotography:

  • atmospheric turbulence, which can distort images and even create false details or make real ones disappear
  • the unavoidable shaking of the telescope due to manual tracking, especially in satellite imaging
  • noise, the variation of brightness or color in images, due to sensor and circuitry of a digital camera, or the diffraction of light from the telescope

These problems may be hard to avoid, depending on your equipment and level of skill. So what should an astrophotographer do?

“The solution for these issues is to be careful with processing,” Legault explained. “I’ve often said the best, most skilled person in imaging processing is not the one that knows all the possibilities of processing, but the person that knows when to stop processing an image.”

Overprocessing

Over-processing, such as multiple smoothing, sharpening and enlargement operations, or layer transformations and combinations in Photoshop can create false details in images.

The issues with the lead image in this article of all the “satellites” — the structures and the different colors you see — are mainly caused by atmospheric turbulence and noise in the raw images, combined with effects from the color sensor in the camera.

Atmospheric Turbulence

Think of how when you look at a star that is low on the horizon with the naked eye, you see twinkling, and sometimes even changes in color, so the atmospheric turbulence can definitely make an effect on colors.

The star Vega again, a series of images put together in an animation: it appears to be a satellite during its flight showing variation of size and apparent rotation. But it is not. Credit: Thierry Legault.

“When you observe a star through a telescope at high magnification, it can become even more distorted,” Legault said. “You have spikes, distortions and changes in shape, and a star that is supposed to be a point or a disk, unfortunately, by turbulence is transformed into something that is completely distorted and can take many shapes.”

Equipment issues

Additionally, Legault said, combining the distortions with an effect from color sensors in the camera, called the Bayer sensor, can cause additional issues.

“For the sensor, you have pixels by groups of four: one red, one blue and two green in square,” Legault said, “and you can easily imagine that if the object is very small, such as a very small star, the light can fall on a red pixel and then the image can become red. Then the image of the star is distorted and you have some spikes that fall on a different color pixel.”

And then the processing does the rest, transforming turbulence and camera artifacts into details that may look real, Legault said.

Legault recalled an amateur who, a few years ago, published an image of Saturn’s moon Titan.

“The image contained surface details and a sharp disk edge,” he said, “and looked quite convincing. But we all know that Titan is covered with an opaque and uniform atmosphere, and surface details can’t be seen. The details were actually only artifacts created from noise or other image defects by over-processing a poor resolution image with multiple upsizing, downsizing, sharpening and smoothing operations.”

What’s an amateur astrophotographer to do?

So, with more and more people doing astrophotography these days, how can they make sure that what they think they are seeing is real?

“There are solutions like combining raw images,” Legault said. “When you combine 10 or 20 or 100 raw images, you can decrease the noise and the image is more reliable and less distorted by turbulence.”

For example, take a look at the images of the space shuttle Discovery below. The two left images are consecutive single frames, processed by smoothing (noise reduction), sharpening (wavelets) and was enlarged 3 times.

The space shuttle discovery imaged in orbit. Credit and copyright: Thierry Legault

The first and second images, although blurry, seem to show lots of very small details. But when they are compared together or with a combination of the 27 best images of the series (on the right), only the larger structures are finally common.

“The bright line marked A is not real, it is an artifact likely caused by turbulence,” Legault said, “and if it were an image of the space station taken during an EVA, I could perhaps claim that this detail is an astronaut, but I would be wrong. The double dark spot marked B, could be taken for windows on top of the cockpit of Discovery. But it is not real; if it were an image of the Space Station, I could claim that it’s the windows of the Cupola, but again I would be wrong. In C, the two parallel lines of the payload bay door is common to both images, but a comparison with the right image, which contains only real details, show that they are not real and that they are probably a processing artifact.”

One of the drawbacks of color sensors is that there is more noise in the image, so the image is less reliable than with black and white sensors. This is the reason that deep sky cameras often use black and white sensors. And so for imaging satellites like the International Space Station, Legault uses a black and white camera.

“It is more reliable, and you don’t need a color camera because the space station is colorless, except for the solar panels,” Legault said. “In addition, the monochrome sensor is much more sensitive to light, by 3 or 4 times. More sensitive means you have less noise.”

Logical advice

Legault’s main advice is just to be logical about what you are seeing in both raw and processed images.

“You need to look at the whole image, the consistency of the whole image, and not just one detail,” he said. “If I take an image that I say has detail on Jupiter’s satellites and on the same image I cannot even see the great red spot on Jupiter, it doesn’t work – that is not possible. The image must have an overall consistency and include details of an object larger than the one that we are interested in. So, if we see an image where someone is supposed to have an astronaut and a module of the space station, and a larger module is not visible or is completely distorted, there is a problem.”

On March 7, 2011 the robotic arm on space shuttle Discovery is used for a last inspection of the protection tiles before landing on the STS-133 mission. Image credit and copyright: Thierry Legault

Another piece of advice is to compare your image to another image taken by someone else — another amateur astrophotographer, a professional or even a space agency.

“If You have a photo of the space shuttle or the space station, for example, you can compare it to a real photo and see if all the details are there,” Legault said.

And if you still have questions about what you are seeing on your own images, Legault also suggests posting your images on astronomy forums so you can get the analysis and insights of other amateur astrophotographers.

“So, there are solutions to make sure that details are real details,” Legault said, “and as you get used to observing raw images and processed images, it will become easier to understand if everything is real, if just a part is real, or if almost nothing is real.”

But Legault’s main advice is not to over-process your images. “Many of amateurs take amazing, sharp images and using gentle and reasonable processing so that there are no artifacts.”

For more information and advice from Thierry Legault, see his website, especially the technical pages. Legault has written a detailed article for the March issue of Sky & Telescope on how to image the International Space Station.

You can also read our article on Legault’s astrophotography, published on March 1, 2012.