Posted on by Jenny Winder

Venus Transit — There’s an App for That!

Transit of Venus by NASA's TRACE spacecraft Image credit: NASA/LMSAL
Transit of Venus in 2004 by NASA's TRACE spacecraft. Image credit: NASA/LMSAL

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There have been only six Venus transits since the invention of the telescope in the early 17th century. It was not until 1761 that the transit of Venus on June 6th was observed as part of the first ever international scientific observation project, instigated by Edmond Halley. Astronomers across the globe viewed the transit and the differences in their observations were used to triangulate the distance to Venus and, using Kepler’s laws, the distance to the Sun, the other planets and the size of the Solar System. Though the method used has not changed in the 251 years since, the equipment most certainly has.

For this transit, we have technology on our side.

In previous Venus Transits, expeditions were sent out far and wide and the 1761 transit was eventually recorded by 120 individual astronomers from 62 locations across Europe, America, Asia and Africa. They used only the simple telescopes of the day, fitted with dense filters, a pendulum clock to time the transit and quadrants to determine their exact latitude and local time. It is hardly surprising that their observations varied widely. Their calculations put the Sun’s distance between 130 and 158 million kilometres.

Transits happen in pairs. After 121 years a transit occurs followed 8 years later by another, then 105 years pass before the next pair and then the pattern repeats. Prior to the transit of 2004 the most recent transit was in 1882. There were none during the whole of the 20th century! We now approach the last chance to view a transit in our lifetime, the next will not occur until 2117.

Luckily, we’ve got some newly developed technology to help make this the most-observed transit ever!

Astronomers Without Borders are part of the Transit of Venus Project to get as many people around the world to observe the transit and to participate in a collective experiment to measure the Sun’s distance. To this end they have produced the Venus Transit phone app, available to download free for both iTunes and Android. Once downloaded you can start to practice timing the interior contacts of ingress and egress using a simulation of the transit. This is not as easy as it seems, as the black drop effect makes precise timing tricky so practice is definitely recommended. The app will tell you how far out you are so that you can perfect your timing and it will also predict times of contact based on your location together with times of sunrise and sunset.

On the day of the transit, the app will record the exact GPS time and your location, which is sent to the global database. Afterwards you can access your data on the website’s map to edit your entry, and upload descriptions, text, images, or movies and view other entries as well. This transit will be visible over most of the Earth except for parts of West Africa and most of South America, so download, get practicing and become part of a once in a lifetime, global citizen science experiment!

Find out more at Transit of Venus

Posted on by Nancy Atkinson

How the Hubble Telescope Will Look at the Moon to See Venus Transit the Sun

Scientists used the Hubble Space Telescope to look at the Moon to prepare for special observations of the 2012 Venus transit of the Sun. Credit: NASA, ESA, and D. Ehrenreich (Institut de Planetologie et d'Astrophysique de Grenoble (IPAG)/CNRS/Universite Joseph Fourier)

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Venus moving across the face of the Sun, from our vantage point here on Earth, is such a rare event, that astronomers and observatories around the world have been preparing for this year’s Venus Transit, on June 5-6. And one observatory that is literally “around the world,” – the Hubble Space Telescope — is even planning to make observations of this transit event. What, you say? The Hubble telescope can’t look at the Sun – it would fry every component on board! Hubble scientists are being pretty sneaky, if not resourceful so they too can join in the observations.

Since Hubble can’t look at the Sun directly, astronomers are planning to point the telescope at the Moon, using it as a mirror to capture reflected sunlight and isolate the small fraction of the light that passes through Venus’s atmosphere. Imprinted on that small amount of light are the fingerprints of the planet’s atmospheric makeup.

Scientists say these observations will mimic a technique that is already being used to sample the atmospheres of giant planets outside our solar system passing in front of their stars. In the case of the Venus transit observations, astronomers already know the chemical makeup of Venus’s atmosphere, and that it does not show signs of life on the planet. But the Venus transit will be used to test whether this technique will have a chance of detecting the very faint fingerprints of an Earth-like planet, even one that might be habitable for life, outside our solar system that similarly transits its own star.

Venus is an excellent stand in for Earth because of how similar in size and mass it is to our planet.

Several different instruments on Hubble will be used in this special observation. The Advanced Camera for Surveys, Wide Field Camera 3, and Space Telescope Imaging Spectrograph, to view the transit in a range of wavelengths, from ultraviolet to near-infrared light. During the transit, Hubble will snap images and perform spectroscopy, dividing the sunlight into its constituent colors, which could yield information about the makeup of Venus’s atmosphere.

Hubble will observe the Moon for seven hours, before, during, and after the transit so the astronomers can compare the data. Astronomers need the long observation because they are looking for extremely faint spectral signatures. Only 1/100,000th of the sunlight will filter through Venus’s atmosphere and be reflected off the Moon.

Because the astronomers only have one shot at observing the transit, they had to carefully plan how the study would be carried out. Part of their planning included the test observations of the Moon, such as when they took the top image of Tycho Crater.

Hubble will need to be locked onto the same location on the Moon for more than seven hours, the transit’s duration. For roughly 40 minutes of each 96-minute orbit of Hubble around the Earth, the Earth occults Hubble’s view of the Moon. So, during the test observations, the astronomers wanted to make sure they could point Hubble to precisely the same target area.

This is the last time this century sky watchers can view Venus passing in front of the Sun. The next transit won’t happen until 2117. Venus transits occur in pairs, separated by eight years. The last event was witnessed in 2004.

Find more on how you can observe the Venus transit for yourself in this article by Tammy Plotner.

Source: HubbleSite

Posted on by Tammy Plotner

2012 Venus Transit – The Countdown Is On!

Venus 34 Days Before 2012 Transit - Credit: John Chumack

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Head outside on any clear night this week and you won’t be able to miss brilliant Venus decorating the western horizon. Right now it’s surrounded by a host of bright winter stars like Capella, Betelgeuse, Aldebaran and the Pleiades. But, don’t stop there. Use any type of optical aid and you’ll see the planet is in the crescent phase right now and bigger than Jupiter in apparent size!

There’s a lot of things to know about viewing Venus. Oddly enough, the smaller the phase, the more brightly it shines. If you cannot see its slender form for the glare, simply try wearing sunglasses while using your binoculars… or stacking dark filters, such as green and blue, for the telescope eyepiece. While you’d think that something which sparkles and shines like Venus would be very exciting to see magnified, it’s actually pretty bland. However, don’t let rather ordinary appearances fool you. Behind that “girl next door” exterior is a really radical chick. Beneath the bland clouds runaway greenhouse gases heat things up to 860 degrees Fahrenheit (460 degrees Celsius) and volcanoes rule.

Keep on watching Venus. Right now she’s headed towards Earth and the pinnacle of observing excitement – the Transit. It will continue to grow larger in apparent size and the crescent phase will narrow even more. On June 5 (June 6 in Australia and Asia), it will pass between the Earth and Sun… an event which only happens about twice in a century and won’t happen again until the year 2117!

Venus Transit Sequence 2004 - Credt: John Chumack

The clock is ticking and now is the time to begin your preparations to view the transit of Venus. Do not wait until just a few days before the event to choose a location for your observations. If you do, you might find yourself faced with clouds… an obstruction you hadn’t planned on… getting permission to be in a certain area… or many other things. Knowing exactly where the Sun will be during the transit means a relaxed experience!

As of now, you’re going to find it will be very difficult to locate solar filters for particular telescopes – and waiting any longer may mean not having one at all. Because the transit of Venus is such a rare event, many retailers are carrying special eclipse/transit viewing glasses. They will appear much like the cardboard 3D glasses you get at the movie theatre, but instead of red and blue lenses, they will have either black mylar or Baader filter film. These glasses are safe for solar viewing, but there are a few things you must understand about them. Before you view, please inspect the edges carefully to make sure they are sealed and no sunlight can enter. Even more importantly, do not use them in conjunction with binoculars or a telescope. Eclipse glasses were meant strictly for use with your eyes. Concentrating sunlight with an optical aid and hoping the glasses will be enough to block the Sun’s harmful rays is taking a chance at blinding yourself. Always use approved solar filter material when viewing with telescopes or binoculars and always supervise when children are present.

Venus Transit 2004 - Credit: John Chumack

The next tip for viewing the Venus transit has to do with photography. If you plan on filming or photographing the event through a telescope, now is the time to practice. Do not wait until just a few days before the event to be sure your video equipment is working properly – or that your camera is prepared. Start now by taking practice pictures of the Sun and make sure you have spare batteries or a power supply on hand for the day of the event. Nothing is more disappointing than being ready to photograph an astronomical event and having your equipment fail at the last second. It’s always wise to have a back-up option… such as a cell phone camera, spare pocket camera, or even a camcorder handy just in case. All of these will work afocally. If you practice in advance, you’ll find you can take quite satisfactory photos by just holding the camera to a properly filtered telescope eyepiece.

The last tip for viewing the Venus transit is time. Make sure well in advance of exactly what time the transit starts in your area! The local transit times page by Steven van Roode and Francois Mignard is an excellent resource. But don’t forget… the times are given on an astronomical standard – Universal Time. If you are unsure of how to convert, try the Time Zone Converter to assist you.

The clock is ticking… Be ready!

Posted on by Jenny Winder

The Mystery of Venus’ Ashen Light

Venus imaged by Magellan Image Credit: NASA/JPL

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May is the best time to try and spot one of the most enduring unsolved mysteries in our Solar System. Ashen Light is a faint glow allegedly seen on the unlit portion of Venus, during its crescent phase, similar to the earthshine often observed on the Moon, though not as bright. It is more commonly observed while Venus occupies the evening sky, as now, than when it is in the morning sky. But no one really knows for sure what causes it.

So what’s the history of our knowledge about this enigmatic glow?

The phenomenon was first noted in 1643, by Italian astronomer Giovanni Battista Riccioli. Though many notable astronomers have reported sightings in the 369 years since, including Sir William Herschel and more recently, Sir Patrick Moore, many others have failed to see the effect, leading to claims that it is due to nothing more than observer error, an illusion, atmospheric effect or equipment malfunction. Things are not helped by the fact that nobody has managed to capture an image of Ashen Light, yet.

As the month progresses, Venus nears the Sun, ready for its transit on June 5th to 6th and the planet’s crescent phase will increase in diameter during the month, from 37 arcseconds to 56 arcseconds. The best option for amateur astronomers hoping to catch a fleeting glimpse is to use an occulting bar to block the bright crescent, making any glow present on the unlit portion of Venus, more visible.

There is much controversy and many theories as to the cause of Ashen Light. The Keck 1 telescope on Hawaii reported seeing a subtle green glow and suggested it could be produced as ultraviolet light from the Sun splits molecules of carbon dioxide, known to be common in Venus’ atmosphere, into carbon monoxide and oxygen, but the green light emitted as oxygen recombines to form O2 is thought too faint to explain the effect. Another more likely theory is that multiple lightning strikes are illuminating Venus’ skies. Though the Cassini spacecraft flew by Venus twice on it’s voyage to Saturn and failed to detect the high frequency radio noise we associate with thunderstorms on Earth, in 2007 Venus Express did detect low frequency ‘whistler waves’ that can also result from lightning. It could also be the Venusian equivalent of aurorae.

By far the most bizarre theory, and my personal favourite, was proposed in the early 19th century by the Bavarian astronomer Franz von Gruithuisen, who suggested that Ashen Light was the result of fires lit to clear land for farming on Venus, or to celebrate the coronation of a new Venusian Emperor!

For further reading, a paper on Ashen Light by C. T. Russell and J. L. Phillips

Posted on by Ken Kremer

Great ISS Sightings – All Nights this Week of April 9

ISS crossing the evening sky at about 8:40 PM EDT on April 8, 2012 in New Jersey; 25 sec exposure, about 30 degree elevation, looking south. Credit: Ken Kremer.
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    Calling all Skywatching and Space Fans ! This is a great week for observing the International Space Station (ISS), swiftly crossing the evening nighttime sky.

    All this week from Monday thru Saturday, folks all across vast portions of the United States and Canada will be treated to fabulous viewings of the International Space Station. And at very convenient viewing times in the early evening, after dinner and in prime time.

    From Maine to Vancouver, from Ohio to Texas, from Florida to New Mexico – many of you will be in for a rather pleasurable ISS treat.

    Of course the exact viewing times, days, elevations, durations and directions varies greatly depending on your exact location – and clear skies. And the viewing parameters change daily.

    Check out this NASA website for Human Spaceflight Sighting Opportunities. It’s simple. Just plug in your country, state and select a local town. Also check out – Heavens Above.

    This evening, Monday April 9, I shot a few 20 to 30 second exposures as the ISS was speeding past at about a 30 degree elevation. But the best viewings at far higher elevations are yet to come the remainder of this week.

    ISS speeds across evening sky on April 9, 2012. 6 Humans from the US, Russia and the Netherlands are currently living aboard the ISS. Credit: Ken Kremer

    The International Space Station is the brightest manmade object in the night sky and even brighter than Venus depending on orbital mechanics. Only our Sun is brighter. Since Venus is an evening observing target this week, maybe you’ll even be lucky to see the ISS seem to pass close by that hellishly hot planet.

    Have you ever looked at the ISS hurtling overhead ?

    Take some shots and send them to Ken to post here at Universe Today.

    And remember, 6 Humans from the US, Russia and the Netherlands are currently residing aboard the ISS, conducting science research and sending back gorgeous shots of all of us back here on Earth.

Posted on by Nancy Atkinson

Planetary Conjunction Mashup

A triple conjunction between 3 different objects: Venus, The Pleiades and an airplane!! Taken on the 4th Apr 2012, 12:15UT. Credit: Shahrin Ahmad

A Boulder Side of Venus – Conjunctions 2012 from Patrick Cullis on Vimeo.

So far, 2012 has brought us a plethora of planetary conjunctions, with Venus pairing with the Moon, Jupiter and the Pleiades. Not all at the same time, of course, but photographer Patrick Cullis has put them all together in this wonderful timelapse mashup video, which includes the beautiful foreground of the Flatirons of Boulder, CO. “Jupiter and Venus dominated the early days of March, coming within 3 degrees of one another,” writes Patrick. “Then, Venus passed a crescent moon on its way to a meeting with the Seven Sisters, also known as the Pleiades.”

And we’re all waiting for this year’s big conjunction on June 5 or 6, 2012, depending on your location, then the tiny disk of Venus will glide across the face of the Sun. That won’t happen again until 2117.

To complete our conjunction mashup, we’ve got a really unique image, below, of a triple conjunction between 3 different objects, Venus, The Pleiades and an airplane taken on April 4, sent to us by Shahrin Ahmad in Malaysia, PLUS, a wonderful new poem by space’s poet laureate, Stuart Atkinson, about his experiences viewing the recent conjunctions. It’s a must read for any amateur astronomer, putting to words the joys — and disappointments — of lifting your eyes to the heavens!

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CONJUNCTION

By Stuart Atkinson

For weeks I watched them drift towards each other,
Approaching shyly, slyly; two would-be lovers
From a Jane Austen dance, casting furtive glances
Across the ballroom of the golden twilight,
Eyes for no-one else as nightfall drew near.
Venus – lovely and lantern-bright, out-shining
Every other dancer on the floor; Jupiter – fainter
By far but still beaming with a noble light,
Stalking his pretty planetary prey…

The first time I saw them they were still
A third-of-the-sky apart,
But each blazing Turner sunset brought them closer yet,
Each day’s end a little better-placed to gaze
Upon each other’s radiant face,
And a million Earthbound eyes looked on, amazed
To see two such fine celestial jewels
Coming together in the sky.
Some sought out a sheltered, grassy place
Of peace and dark to watch the twin sparks’
Close approach in groups; others stood alone
In overgrown gardens or on concrete roofs,
Marvelling at the view from their light-polluted
Homes, wondering what they would see if only
They could escape the Bright and find a place
Without the blinding security lights’ flares
And streetlights’ orange glare…

Of course, I missed the breathless climax
Of their brief encounter. For half a dozen days
Either side of that ringed-in-red date
My sky was thick with cloud fat and foul,
A star- and planet-hiding shroud draped o’er
The Auld Grey Town that was not pulled away
Until the planet parade had passed by,
And the next time I looked to the west
The best view had come and gone:
Unseen by me, Venus and Jupiter had chastely
Touched fingers then parted, leaving
The lovesick gas giant fading, falling
Forlornly towards the rooftops and trees
While the Goddess of Love soared higher,
Growing ever-brighter as she climbed…

Cheated? Yes. But I have fine memories
Of some magical nights, and a hundred photographs,
Taken from the shores of moonlit, duck-dotted lakes
And crumbling castle walls. Sometimes in company,
More usually alone I stood and watched those distant
Worlds waltzing across the western sky,
My so-often-now world weary eyes
Suddenly wide again with wonder at the beauty of it all,
Listening to them calling “Look at us! See
How gloriously we shine above your sleepy little town…!”

…Far apart now, their dusky dalliance a thing of the past,
Venus and Jupiter are just bright stars once more;
The night sky’s restless showbiz spotlight has swept on,
Picking out Saturn, Mars and a waning Moon,
The Great Conjunction relegated
To Celestial Celebrity Has Been history.

Which is how it should be.

The Earth turns, and turns, and turns, setting a universe
Of stars and planets wheeling around pale Polaris,
Lovely and sentinel-still,
While the Milky Way floats serenely
Through her snow-globe of glitter-flake galaxies,
The prickling breeze of a billion billion suns’ solar winds
Blowing on the faces of the few evolved apes
Brave enough to lift their eyes from the grey
Landscapes of their everyday lives and catch
A fleeting glimpse of beauty in the Great Beyond…

© Stuart Atkinson 2012

Posted on by Nancy Atkinson

Astrophotos from Around the World of the Venus-Pleiades Conjunction

Venus at The Seven Sisters, M45 Pleiades on 04-04-2012. Credit and copyright John Chumack.

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The past several evenings, Venus has been snuggling up to one of the most famous star clusters, the Pleiades. Universe Today readers have taken some beautiful images of that event, and they have generously shared them with us. Above is John Chumack’s stunning view from Ohio in the US; see below for more images from around the world!

The Pleiades, also known at the Seven Sisters, is a beautiful bright blue open star cluster 440 light years from Earth. Only once every eight years does this conjunction take place.


Venus within the Pleiades on April 4, 2012, as seen from New Jersey in the US. Credit and copyright John Anton.

John Anton took this pretty image from New Jersey in the US. “It was a beautiful sight,” he said.

Astronomers say that the relative tightness of the cluster indicates this is a young group of stars, and the member stars were formed about 100 million years ago and will probably travel together through space as a bound cluster for another 250 million years before the gravity of the Milky Way breaks up the cluster into individual field stars.

Venus and the Pleiades from San Diego, USA. Credit: Paul Miller
Venus and the Pleiades from the UK. Credit: Dave Liddicott.

“An old SLR 70-210mm zoom lens on my DMC-G10. 5 second exposure, 1600 ISO. Tree illuminated partly by a neighbours light and partly by the built in flash on the camera,” says Dave Liddicott.

The view of Venus and the Pleiades from Norway. Credit: Sirrka Stephens

Sirrka Stephens from Norway took her image using a Panasonic Lumix DMC-F62, Leica 35mm, 30 sec., f/2.8, ISO 80, rotated to the left.

The Venus-Pleiades conjunction from Lebanon.Credit: Space Weed

“Space Weed” from Beirut, Lebanon took this image on April 3, 2012. “2 second exposure, ISO 1600, f 5.9, Stack of 40 images and 18 dark frames, Level correction in Photoshop,” Space Weed reports.

Venus shines brilliantly as it passies by the Pleiades star cluster on April 2, 2012. Credit: Tavi Greiner.

Tavi Greiner on the east coast of the US took this lovely image on April 2, 2012.

Venus and the Pleiades on April 3, 2012. Credit: Austin Russie

Another beautiful view from Austin Russie. “A luminous Venus passes directly between Earth and an elusive cluster of stars known as the Pleiades,” he says.

A double exposure, showing how Venus shifted in two hours' time. Credit: L. Laveder - TWAN

Laurent Laveder from France sent in this unusual image showing the shifting of Venus in the Pleiades in two hours’ time.

Image of the conjunction between Venus and M45 Pleiades in the middle of the trees, taken in Fonte-de-Telha, a small pine forest in Portugal. Credit: Miguel Claro

The final image is by Miguel Claro from Portugal, who can be seen enjoying the stars with binoculars “in a peaceful moment,” he said.

There are more images on UT’s Flick page, so check them out!

Want to get your astrophoto featured on Universe Today? Join our Flickr group, post in our Forum or send us your images by email (this means you’re giving us permission to post them). Please explain what’s in the picture, when you took it, the equipment you used, etc.

Editor’s note: Apologies for the irregular formatting of this article — we’re working to fix it!

Posted on by Nancy Atkinson

Watch Live Webcast of Venus-Pleiades Conjunction April 4, 2012

Venus on April 3, 2012, when it last passed over the Seven Sisters cluster. Credit: Bob King

There’s a nice meetup in the heavens tonight: bright Venus is snuggling up to one of the most famous star clusters, the Pleiades. The Slooh Space Camera is broadcasting a live, real-time feed of the most famous star cluster in the heavens, the Pleiades, meeting up with our nearest and brightest planetary neighbor, Venus. Slooh’s coverage will begin on Wednesday, April 4th starting at 1:30 PM PDT / 4:30 PM EDT / 20:30 UT. (This was originally scheduled for April 3rd, but was rescheduled due to high humidity at Canary Islands observatory off the coast of Africa.) The broadcast can be watched here, or accessed at Slooh’s homepage or by visiting Slooh’s G+ page, where you will be able to see the panel interact live via G+ Hangouts On Air.

If skies are clear, you can see the conjunction for yourself by looking toward the west in the constellation Taurus, after sunset, using binoculars. If you can get images of the event, we’ll post views of them. Share them on Universe Today’s Flickr page.

Continue reading “Watch Live Webcast of Venus-Pleiades Conjunction April 4, 2012”

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 Nancy Atkinson

Astrophoto: Conjunction Symmetry by Rick Ellis

Multiple images of the Venus-Jupiter conjuction on Mar. 13, 2012 from Toronto, Canada. Credit: Rick Ellis.

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It’s poetry in motion! Rick Ellis from Toronto, Canada created this 27 frame-composite of the conjunction between Venus and Jupiter on March 13, 2012, with 6 second exposures five minutes apart. Rick used a Canon A460, ISO 80.

Beautiful!

Check out Rick’s website for more poetry — seriously — and more images.

See our previous gallery of Venus-Jupiter conjunction images from around the world.

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