Saturn Archives

April 26, 2012January 7, 2016 by Ken Kremer

Outer Space – Mind Blowing Video from Jupiter and Saturn

Video Caption: This mesmerizing video unveils incredibly amazing sequences around Jupiter and Saturn from NASA’s Cassini and Voyager missions set to stirring music by “The Cinematic Orchestra -That Home (Instrumental)”. Credit: Sander van den Berg

Don’t hesitate 1 moment ! Look and listen to this mind blowing video of the Jupiter and Saturnian systems.

If you love the wonders of the hitherto unknown Universe unveiled before your eyes – and long to explore – feast your eyes on this short new video right now titled simply; “Outer Space”. Continue reading “Outer Space – Mind Blowing Video from Jupiter and Saturn”

April 23, 2012December 23, 2015 by Nancy Atkinson

Glittering ‘Mini-Jets’ Found in Saturn’s Curious F-Ring

This set of six images obtained by NASA's Cassini spacecraft shows trails that were dragged out from Saturn's F ring by objects about a half mile (1 kilometer) in diameter. Scientists have seen more than 500 of these kinds of trails in over 20,000 images collected by Cassini from 2004 to 2011. Credit: NASA/JPL-Caltech/Space Science Institute

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New images from the Cassini spacecraft have revealed kilometer-sized objects piercing through parts of Saturn’s F ring, leaving glittering trails behind them. These trails in the rings, which scientists are calling “mini-jets,” provide insight into the curious behavior of the F ring, which Cassini imaging team leader Carolyn Porco called “Saturn’s most beguiling phenomena.” With new detailed images, Cassini reveals the intricate workings of the F ring and hordes of tiny moonlet companions creating the trails.

“I think the F ring is Saturn’s weirdest ring, and these latest Cassini results go to show how the F ring is even more dynamic than we ever thought,” said Carl Murray, a Cassini imaging team member from Queen Mary University of London, England. “These findings show us that the F ring region is like a bustling zoo of objects from a half mile [kilometer] in size to moons like Prometheus a hundred miles [kilometers] in size, creating a spectacular show.”

f-ring-full — Images from NASA's Cassini spacecraft have revealed half-mile-sized (kilometer-sized) objects punching through parts of Saturn's F ring, leaving glittering trails behind them. Credit: NASA/JPL-Caltech/Space Science Institute

Scientists have known that relatively large objects like Prometheus (as long as 92 miles, or 148 kilometers, across) can create channels, ripples and snowballs in the F ring. But scientists didn’t know what happened to these snowballs after they were created, Murray said. Some were surely broken up by collisions or tidal forces in their orbit around Saturn, but now scientists have evidence that some of the smaller ones survive, and their differing orbits mean they go on to strike through the F ring on their own.

PIA15502 — This image obtained by NASA's Cassini spacecraft around the time it went into orbit around Saturn in 2004 shows a short trail of icy particles dragged out from Saturn's F ring. Credit: NASA/JPL-Caltech/Space Science Institute

These small objects appear to collide with the F ring at gentle speeds – something on the order of about 4 mph (2 meters per second). The collisions drag glittering ice particles out of the F ring with them, leaving a trail typically 20 to 110 miles (40 to 180 kilometers) long. Murray’s group happened to see a tiny trail in an image from Jan. 30, 2009 and tracked it over eight hours. The long footage confirmed the small object originated in the F ring, so they went back through the Cassini image catalog to see if the phenomenon was frequent.

“The F ring has a circumference of 550,000 miles [881,000 kilometers], and these mini-jets are so tiny they took quite a bit of time and serendipity to find,” said Nick Attree, a Cassini imaging associate at Queen Mary. “We combed through 20,000 images and were delighted to find 500 examples of these rogues during just the seven years Cassini has been at Saturn.”

In some cases, the objects traveled in packs, creating mini-jets that looked quite exotic, like the barb of a harpoon. Other new images show grand views of the entire F ring, showing the swirls and eddies that ripple around the ring from all the different kinds of objects moving through and around it.

“Beyond just showing us the strange beauty of the F ring, Cassini’s studies of this ring help us understand the activity that occurs when solar systems evolve out of dusty disks that are similar to, but obviously much grander than, the disk we see around Saturn,” said Linda Spilker, Cassini project scientist based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “We can’t wait to see what else Cassini will show us in Saturn’s rings.”

See more images and animations at the CICLOPS website.

Source: JPL

April 22, 2012December 23, 2015 by Tammy Plotner

Weekly SkyWatcher’s Forecast: April 23-29, 2012

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Greetings, fellow SkyWatchers! What a great week to just enjoy some great unaided eye astronomy observations. Who can resist the beautiful appearance of Mars in Leo? Also this week, you’ll enjoy not one – but two – meteor showers as the Mu Virginids come to town mid-week and the Bootids light up the weekend. Get ready to enjoy bright stars, find planets, explore lunar features, learn some astronomy history and much more! When ever you’re ready, meet me in the back yard…

Monday, April 23 – Pioneer quantum physicist Max Planck was born on this day in 1858. In 1900, Max developed the Planck equation to explain the shape of blackbody spectra (a function of temperature and wavelength of emission). A “blackbody” is any object that absorbs all incident radiation – regardless of wavelength. For example, heated metal has blackbody properties because the energy it radiates is thermal. The blackbody spectrum’s shape remains constant, and the peak and height of an emitter can be measured against it – be it cosmic background radiation – or our own bodies.

Now, let’s put this knowledge into action. Stars themselves approximate blackbody radiators, because their temperature directly controls the color we see. A prime example of a “hot” star is Alpha Virginis, better known as Spica. Compare its color to the cooler Arcturus… What colors do you see? There are other astronomical delights that radiate like blackbodies over some or all parts of the spectrum as well. You can observe a prime example in a nebula such as M42, in Orion. By examining the radio portion of the spectrum, we find the temperature properly matches that of electrons involved in the process of fluorescence. Much like a common household fixture, this process is what produces the visible light we can see.

Tuesday, April 24 – Today in 1970, China launched its first satellite. Named Shi Jian 1, it was a successful technological and research craft. This achievement made China the fifth country to send a vessel into space.

Tonight see if you can spot the tender beginnings of the Moon after sunset. Observers take pleasure in sweeping the sky with small scopes and binoculars in hopes of finding the thinnest possible lunar crescent. And speaking of crescents, did you spot Venus close to the Moon? Why not take out your telescope and see what phase Venus is now in. If you don’t have a filter to cut its bright glare, try wearing sunglasses!

No telescope? No problem. You can still do some very awesome astronomy with just your eyes! Begin with locating the northern constellation of Ursa Major – most commonly known as the “Big Dipper”. Take note of the curve of the Dipper’s “handle” and trace it from the bottom of the cup and continue on the “Arc to Arcturus”. Keep moving, because now you’re going to “Speed on to Spica”! Once you’ve located this bright, blue/white star, simply look to its east/southeast (or upper left) for a yellow appearing “star”. That’s no star… That’s Saturn!

Now let’s have a look at 140 light-year distant Epsilon Hydrae – the northernmost star in the small circlet east of Procyon. While it and Rho will make a beautiful visual double for binoculars, Epsilon itself is a multiple system. Its A and B components are a tough split for any scope, but the 8th magnitude C star is easier. The D component is a dwarf star.

Wednesday, April 25 – Today marks the 15th anniversary of the deployment of Hubble Space Telescope. While everyone in the astronomical community is well aware of what this magnificent telescope “sees,” did you know that you can see it with just your eyes? The HST is a satellite that can be tracked and observed. Visit heavens-above.com and enter your location. This page will provide you with a list of visible passes for your area. Although you can’t see details of the scope itself, it’s great fun to track with binoculars or see the Sun glinting off its surface in a scope.

Tonight our first voyage is to the Moon’s surface. Look along the terminator in the southern quadrant and revisit ancient old crater Furnerius. Named for French Jesuit mathematician George Furner, this crater spans approximately 125 kilometers and is a lunar club challenge. Power up and look for two interior craters. The smaller is crater A and it spans a little less than 15 kilometers and drops to a depth of over 1000 meters. The larger crater C is about 20 kilometers in diameter, but goes far deeper, to more than 1400 meters. That’s about as deep as a coral will grow under the Earth’s oceans!

Keep a watch on the skies while you’re out as the Mu Virginid meteor shower reaches its peak at 7 to 10 per hour. With dark skies tonight, you still might catch one of these medium speed meteors radiating from a point near the constellation of Libra.

Thursday, April 26 – On this date in 1920, the Shapely-Curtis debate raged in Washington on the nature of and distance to spiral nebulae. Shapely claimed they were part of one huge galaxy to which we all belonged, while Curtis maintained they were distant galaxies of their own. Thirteen years later on the same date, Arno Penzias was born. He went on to become a Nobel Prize winner for his part in the discovery of the cosmic microwave background radiation, through searching for the source of the “noise” coming from a simple horn antenna. His discovery helped further our understanding of cosmology in ways that Shapely and Curtis could have never dreamed of.

Perhaps they dreamed of Moon? We’ve got Moon! No matter, what we really want to do is revisit and study a changeable, sometimes transient, and eventually bright feature on the lunar surface – crater Proclus. At around 28 kilometers in diameter and 2400 meters deep, Proclus will appear on the terminator on the west mountainous border of Mare Crisium. For many viewers tonight, it will seem to be about 2/3 black, but 1/3 of the exposed crater will be exceptionally brilliant – and with good reason. Proclus has an albedo, or surface reflectivity, of about 16%, which is an unusually high value for a lunar feature. Watch this area over the next few nights as two rays from the crater will widen and lengthen, extending approximately 322 kilometers to both the north and south. Congratulations on another lunar club challenge!

Friday, April 27 – Tonight we’re heading towards the lunar surface to view a very fine old crater on the northwest shore of Mare Nectaris – Theophilus. Slightly south of mid-point on the terminator, this crater contains an unusually large multiple-peaked central mountain which can be spotted in binoculars. Theophilus is an odd crater, one that is a parabola – with no area on the floor being flat. It stretches across a distance of 100 kilometers and dives down 440 meters below the surface. Tonight it will appear dark, shadowed by its massive west wall, but look for sunrise on its 1400 meter summit!

Now, let’s try picking up a globular cluster in Hydra that is located about 3 fingerwidths southeast of Beta Corvus and just a breath northeast of double star A8612 – M68 (Right Ascension:12 : 39.5 – Declination: -26 : 45). This class X globular was discovered in 1780 by Charles Messier and first resolved into individual stars by William Herschel in 1786. At a distance of approximately 33,000 light-years, it contains at least 2000 stars, including 250 giants and 42 variables. It will show as a faint, round glow in binoculars, and small telescopes will perceive individual members. Large telescopes will fully resolve this small globular to the core!

While you’re out, have a look at 27 Hydrae about a fingerwidth southwest of Alpha. It’s an easy double for any equipment with its slightly yellow 5th magnitude primary and distant, white, 7th magnitude secondary. Although it is wide, the pair is a true binary system.

Saturday, April 28 – Today was a very busy day in astronomy history. Newton published his Principia in 1686 on April 28. In 1774, Francis Baily was born. He went on to revise star catalogs and explain the phenomenon at the beginning and ending of a total solar eclipse which we know as “Baily’s Beads.” 1900 saw the birth of Jan Hendrick Oort, who quantified the Milky Way’s rotation characteristics and envisioned the vast, spherical area of comets outside our solar system that we now call the Oort Cloud. Last, but not least, was the birth of Bart Jan Bok in 1906 who studied the structure and dynamics of the Milky Way.

Tonight’s outstanding lunar feature will be crater Maurolycus just southwest of the three rings of Theophilus, Cyrillus and Catharina. This lunar club challenge spans 114 kilometers and goes below the lunar surface by 4730 meters. Be sure to look for Gemma Frisius just to its north.

Now let’s check out a dandy little group of stars that are about a fistwidth southeast of Procyon and just slightly more than a fingerwidth northeast of M48. Called C Hydrae, this group isn’t truly gravitationally bound, but is a real pleasure to large binoculars and telescopes of all sizes. While they share similar spectral types, this mixed magnitude collection will be sure to delight you!

For SkyWatchers, no equipment is necessary to enjoy the Alpha Bootid meteor shower – despite the Moon. Pull up a comfortable seat and face orange Arcturus as it climbs the sky in the east. These slow meteors have a fall rate of 6 to 10 per hour and leave very fine trails, making an evening of quiet contemplation most enjoyable.

Sunday, April 29 – Before we explore space, let’s have a look at the Moon and the close apparition of Regulus and Mars! The three make a wonderful “line up” the night sky! Now, let’s start our lunar observations tonight as challenge craters Cassini and Cassini A come into view just south of the black slash of the Alpine Valley. The major crater spans 57 kilometers and reaches a floor depth of 1240 meters. The challenge is to also spot the central crater A, which is only 17 kilometers wide, yet drops down another 2830 meters below the surface.

While we’re out, have a look at R Hydrae about a fingerwidth east of Gamma – which is a little more than fistwidth south of Spica. R is a beautiful, red, long-term variable first observed by Hevelius in 1662. Located about 325 light-years from us, it’s approaching – but not that fast. Be sure to look for a visual companion star as well!

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

Many thanks to John Chumack of Galactic Images for his outstanding photo of “Leo In Mars”!

April 19, 2012December 23, 2015 by Jason Major

African Lake Has a Twin on Titan

Titan's Ontario Lacus is found to bear a striking resemblance to Namibia's Etosha Pan. (NASA/JPL/ESA)

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A large lake on Saturn’s cloud-covered Titan seems very similar to the Etosha Pan, a salt-encrusted dry lakebed in northern Namibia that periodically fills with water. As it turns out, Titan’s “great lake” may also be temporary.

Ontario Lacus, so named because of its similarity both in shape and size to Lake Ontario here on Earth, was first discovered near the south pole of Titan by the Cassini spacecraft in 2009. Its smooth, dark appearance in radar images indicated a uniform and reflective surface, implying a large — although likely shallow — body of liquid.

Of course, on Titan the liquid isn’t water — it’s methane, which is the main ingredient of the hydrologic cycle found on the giant moon. That far from the Sun the temperatures at Titan’s poles fall to a frigid -300ºF (-185ºC), much too cold for water to exist as a liquid and so, on this world, methane has taken its place.

A research team led by Thomas Cornet of the Université de Nantes, France has taken a closer look at Cassini’s radar data of Ontario Lacus and found evidence of channels carved into the southern portion. According to the team, this likely indicates that the lakebed surface is exposed.

dn17665-1_500 — Cassini image of Ontario Lacus. (NASA/JPL/SSI)

“We conclude that the solid floor of Ontario Lacus is most probably exposed in those areas,” said Cornet.

In addition, sediment layers surrounding the lake suggest that the liquid level has varied.

All in all, this reveals a striking resemblance between Ontario Lacus and Namibia’s Etosha Pan — an “ephemeral lake” that is dry for much of the year, occasionally filling with a shallow layer of water which evaporates, leaving salty rings of sediment.

The inherent otherworldly nature of Etosha Pan is further underlined — and perhaps foreshadowed! — by its use as a backdrop in the 1968 sci-fi film 2001: A Space Odyssey.

Although Ontario Lacus was initially thought to be permanently filled with liquid hydrocarbons, the team’s findings draw a strong correlation with this well-known Earthly environment, suggesting a much more temporary nature and showing the value of comparative research.

20120415-namibia2-full — Satellite image of Etosha Pan, acquired on April 28, 2012. (Chelys/EOSnap)

“These results emphasise the importance of comparative planetology in modern planetary sciences,” said Nicolas Altobelli, Cassini project scientist for ESA.”Finding familiar geological features on alien worlds like Titan allows us to test the theories explaining their formation.”

Read the press release from ESA here.

Image credits: Cassini radar image JPL/NASA. Envisat radar image ESA. Composite image: LPGNantes.

April 16, 2012December 23, 2015 by Jason Major

Cassini Slips Through Enceladus’ Spray

Cassini's latest view of Enceladus' icy spray, acquired on April 14, 2012.

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Spray it again, Enceladus! This Saturday the Cassini spacecraft paid another visit to Enceladus, Saturn’s 318-mile-wide moon that’s become famous for its icy geysers.During its latest close pass Cassini got a chance to “taste” Enceladus’ spray using its ion and neutral mass spectrometer, giving researchers more information on what sort of watery environment may be hiding under its frozen, wrinkled surface.

The image above shows a diagonal view of Enceladus as seen from the night side. (The moon’s south pole is aimed at a 45-degree angle to the upper right.) Only by imaging the moon backlit by the Sun can the geysers of fine, icy particles be so well seen.

During the flyby Cassini passed within 46 miles (74 km) of Enceladus’ surface.

This image was captured during the closest approach, revealing the distressed terrain of Enceladus’ south pole. Although a bit blurry due to the motion of the spacecraft, boulders can be made out resting along the tops of high , frozen ridges. (Edited from the original raw image to enhance detail.)

W00073473 (edit) — Enceladus' southern fissures, the source of its spray. (NASA/JPL/SSI/J. Major)

This flyby occurred less than three weeks after Cassini’s previous visit to Enceladus. Why pay so much attention to one little moon?

Basically, it’s the one place in our solar system that we know of where a world is spraying its “habitable zone” out into space for us to sample.

“More than 90 jets of all sizes near Enceladus’s south pole are spraying water vapor, icy particles, and organic compounds all over the place,” said Carolyn Porco, planetary scientist and Cassini Imaging science team leader, during a NASA interview in March. “Cassini has flown several times now through this spray and has tasted it. And we have found that aside from water and organic material, there is salt in the icy particles. The salinity is the same as that of Earth’s oceans.

“In the end, it’s the most promising place I know of for an astrobiology search,” said Porco. (Read the full interview here.)

N00185749 — A crescent-lit Enceladus sprays its "habitable zone" out into space.

Not to be left out, Tethys was also paid a visit by Cassini. The 662-mile-wide moon boasts one of the most extensively cratered surfaces in the Solar System, tied with its sister moons Rhea and Dione. In this raw image captured by Cassini on April 14, we can see some of the moon’s ancient, larger craters, including Melanthius with its enormous central peak.

tethys-4-14-12-melanthius — Saturn's moon Tethys, imaged by Cassini on April 14, 2012.

Cassini passed Tethys at a distance of about 6,000 miles (9000 km) after departing Enceladus. Cassini’s composite infrared spectrometer looked for patterns in Tethys’ thermal signature while other instruments studied the moon’s geology.

Image credits: NASA/JPL/Space Science Institute. See more images from the Cassini mission on the CICLOPS site here.

April 14, 2012December 23, 2015 by Tammy Plotner

Weekly SkyWatcher’s Forecast – April 16-22, 2012

Messier 83 - Credit: Bill Schoening/NOAO/AURA/NSF

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Greetings, fellow SkyWatchers! It’s International Dark Skies Week and a great time to enjoy astronomy! We’ll start off with an impressive galaxy for even small optics and enjoy two meteor showers. There are planets and planetary nebula to explore, as well as some awesome globular clusters. If you’re in the mood, there’s some history to learn and plenty of astronomy facts! Whenever you’re ready, meet me in the back yard…

Monday, April 16 – Before binocular observers begin to feel that we have deserted them, let’s drop in on a binocular and very small telescope galaxy that resides roughly a handspan below Spica – M83 (Right Ascension: 13 : 37.0 – Declination: -29 : 52). Starhop instructions are not easy for this one, but look for a pair of twin stars just west of the easily recognized “box” of Corvus – Gamma and R Hydrae. You’ll find it about four fingerwidths further south of R.

As one of the brightest galaxies around, the “Southern Pinwheel” was discovered by Lacaille in 1752. Roughly 10 million light-years distant, M83 has been home to a large number of supernova events – one of which was even detected by an amateur observer. To binoculars it will appear as a fairly large, soft, round glow with a bright core set in a delightful stellar field. As aperture increases, so do details – revealing three well defined spiral arms, a dense nucleus and knots of stars. It is truly a beauty and will become an observing favorite!

Tuesday, April 17 – Today in 1976, the joint German and NASA probe Helios 2 came closer to the Sun than any other spacecraft so far. One of its most important contributions helped us to understand the nature of gamma ray bursts.

Are you ready for even more meteors? Tonight is the peak of the Sigma Leonids. The radiant is located at the Leo/Virgo border, but has migrated to Virgo in recent years. Thanks to Jupiter’s gravity, this shower may eventually become part of the Virginid Complex as well. The fall rate is very low at around one to two per hour. While you’re watching this region of sky, be sure to check out the close pairing of Saturn and Spica!

With tonight’s dark skies, this would be a perfect time for larger telescopes to discover an unusual galaxy grouping in Hydra about 5 degrees due west of the Xi pairing (RA 10 36 35.72 Dec -27 31 03.2).

Centralmost are two fairly easy ellipticals, NGC 3309 and NGC 3311, accompanied by spiral NGC 3322. Far fainter are other group members, such as NGC 3316 and NGC 3314 to the east of the 7th magnitude star and NGC 3305 north of the 5th magnitude star. While such galaxy clusters are not for everyone, studying those very faint fuzzies is a rewarding experience for those with large aperture telescopes.

Wednesday, April 18 – Before we have any Moon to contend with, let’s head out in search of an object that is one royal navigation pain for the northern hemisphere, but makes up for it in beauty. Start with the southernmost star in Crater – Beta. If you have difficulty identifying it, it’s the brightest star east of the Corvus rectangle. Now hop a little more than a fistwidth southeast to reddish Alpha Antilae. Less than a fistwidth below, you will see a dim 6th magnitude star that may require binoculars in the high north. Another binocular field further southwest and about 4 degrees northwest of Q Velorum is our object – NGC 3132 (RA 10 07 01.76 – Dec -40 26 11.1). If you still have no luck, try waiting until Regulus has reached your meridian and head 52 degrees south.

More commonly known as the “Southern Ring” or the “Eight Burst Planetary,” this gem is brighter than the northern “Ring” (M57) and definitely shows more details. It can be captured in even small instruments, larger ones will reveal a series of overlapping shells, giving this unusual nebula its name.

Thursday, April 19 – Today in 1971, the world’s first space station was launched – the Soviet research vessel Salyut 1. Six weeks later, Soyuz 11 and its crew of three docked with the station, but a mechanism failed denying them entry. The crew carried out their experiments, but were sadly lost when their re-entry module separated from the return spacecraft and depressurized. Although the initial phase of Salyut 1 seemed doomed, the mission continued to enjoy success through the early 1980s and paved the way for Mir.

Tonight let’s try picking up a globular cluster in Hydra that is located about 3 fingerwidths southeast of Beta Corvus and just a breath northeast of double star A8612 – M68 (Right Ascension: 12 : 39.5 – Declination: -26 : 45).

This class X globular was discovered in 1780 by Charles Messier and first resolved into individual stars by William Herschel in 1786. At a distance of approximately 33,000 light-years, it contains at least 2000 stars, including 250 giants and 42 variables. It will show as a faint, round glow in binoculars, and small telescopes will perceive individual members. Large telescopes will fully resolve this small globular to the core!

Friday, April 20 – By 1850, Lord Rosse had used the 72 inch speculum-mirrored “Leviathon at Parsontown” (Birr Castle, Ireland) to catalogue fourteen previously indecipherable glowing clouds in deep space as “spiral nebulae.” The very first one resolved was originally a discovery of Charles Messier – found while chasing a comet on the night of October 13, 1773. That discovery, M51, had to wait 72 years until large reflecting telescopes unveiled its spiral form. It would take another 75 years before M51’s extragalactic nature became an indisputable fact. Interestingly, observers have now become so accustomed to seeing spiral structure in brighter galaxies that even mid-sized scopes can see M51 (Right Ascension: 13 : 29.9 – Declination: +47 : 12) – the Whirlpool Galaxy – as a “Grand Spiral.” Tonight see what Rosse saw for yourself.

Start in Ursa Major by locating Mizar (Zeta) and Alkaid (Eta), then rotate the line between these two 90 degrees south using Eta as the pivot. With the line oriented to the southwest, cut it in half. With good conditions and a mid-sized scope, you can be initiated into the mystery of the spiral nebulae – nebulae whose individual stars had to await the development of very large professional scopes and long-exposure photography to reveal their stellar nature to the questing human imagination!

Saturday, April 21 – It’s Saturday night and we’ve got New Moon! Tonight, let’s use our binoculars and telescopes and take a look at a spectacular stellar sphere. Let’s find one of the best northern hemisphere globular clusters – M3! You can locate M3 (Right Ascension: 13 : 42.2 – Declination: +28 : 23) easily by identifying Cor Caroli (Alpha Canes Venatici) and Arcturus. Sweep your binoculars along a line halfway between the two and you will uncover this condensed beauty just east of Beta Comae. With added inches and magnification, the stars are out to play!

Discovered by Charles Messier on May 3, 1764, this condensed ball of approximately a half million stars is one of the oldest formations in our galaxy. At 35-40,000 light years distant, this awesome globular cluster spans 220 light years and is believed to be 10 billion years old.

Sunday, April 22 – Today celebrates the birthday of Sir Harold Jeffreys, who was born in 1891. Jeffreys was an astrogeophysicist and the first person to envision Earth’s fluid core. He also helped in our understanding of tidal friction, general planetary structure, and the origins of our solar system.

Start your moonless morning off before dawn with a chance to view the peak of the Lyrid meteor shower. Since the radiant is near Vega, you will improve your chances of spotting them when the constellation of Lyra is as high as possible. This stream’s parent is Comet Thatcher, and it produces around 15 bright, long-lasting meteors per hour!

Before you begin your observations tonight, be sure to check out the cool triangulation of Theta Leonis, Regulus and Mars!

Let’s begin tonight in eastern Hydra and pick up another combination Messier/Herschel object. You’ll find M48 (Right Ascension: 8 : 13.8 – Declination: -05 : 48) easily just a little less than a handspan southeast of Procyon.

Often called a “missing Messier,” Charles discovered this one in 1711, but cataloged its position incorrectly. Even the smallest of binoculars will enjoy this rich galactic cluster filled with more than 50 members including some yellow giants. Look for a slight triangle shape with a conspicuous chain of stars across its center. Larger telescopes should use lowest power since this will fill the field of view and resolve splendidly. Be sure to mark your notes for both a Messier object and Herschel catalog H VI 22!

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

April 13, 2012December 23, 2015 by Nancy Atkinson

See Big and Bright Saturn at Opposition This Weekend

Saturn on April 3, 2012 with the moons Dione (Top-Left) and Tethys (Bot.-Right) as the ringed planet approaches opposition.Credit: Efrain Morales.

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Now is the time to take a look at the planet Saturn, as the ringed planet will be at opposition this weekend, making its closest approach to Earth on April 15, 2012. Its face will be fully illuminated by the Sun, so get out those telescopes, binoculars and your imaging equipment! We want to see your photos! Efrain Morales from the Jaicoa Observatory took this image of Saturn and some of its moons on April 3.

The giant planet’s rings are now optimally angled at over 13 degrees, revealing them better than they have appeared in the past five years. To see the rings of Saturn during opposition, in the northern hemisphere point your telescopes east to southeast at nightfall and south around midnight. For reference, Saturn will be near the bright star Spica, in the constellation Virgo. In the southern hemisphere, Saturn will be above the eastern horizon at 10pm local time, still near Spica.

If the skies aren’t clear in your area, the Slooh Space Observatory will broadcast a free, real-time feed of Saturn at opposition. Their coverage will begin on Sunday, April 15th, starting at 6:30 p.m. PDT/9:30 p.m. EDT/01:30 UTC (April 16th). Slooh will provide two distinct observatory feeds — one from a remote location in South Africa and the second from their world-class observatory site in Canary Islands off the coast of Africa. The broadcast can be accessed at Slooh’s homepage or by visiting Slooh’s Google+ page, where you will be able to see a panel of experts interact live via G+ Hangouts On Air.

The experts include Duncan Copp, producer of many astronomical documentaries, including “In the Shadow of the Moon”; Amanda Hendrix, Cassini’s deputy project scientist from NASA’s Jet Propulsion Laboratory; and Bob Berman, author of numerous astronomy books and contributing editor and monthly columnist for Astronomy Magazine.

“In 40 years of observing the heavens and watching people’s reactions to celestial glories, I’ve found that no object elicits more amazement and sheer wonder than Saturn. I am thrilled to be part of Slooh’s live close-up visit to that magnificent planet,” said Bob Berman.

Send us your images of Saturn by joining our Flickr group, or send us your images by email (this means you’re giving us permission to post them). Please explain when and where you took it, the equipment you used, etc.

April 7, 2012December 23, 2015 by Tammy Plotner

Weekly SkyWatcher’s Forecast: April 9-15, 2012

[/caption]Greetings, fellow SkyWatchers! It’s shaping up to be a great week to enjoy astronomy. For both hemispheres, the Virginid Meteor shower is underway and its peak occurs late Monday night / early Tuesday morning. Need more celestial fireworks? Then keep looking up as the “April Fireballs” will be visiting, with their peak beginning about a week from today and lasting for 24 days. Even if you only catch one of these bright travelers as they sparkle across the starry sky, it will make your night! But hang on, there will be plenty to explore. Bright stars and bright planets are featured – as well as some of the season’s best galaxies. Keep your telescope out and don’t get spooked, because the “Ghost of Jupiter” will be a challenge object! If you want to know more about astonomy history, and what you can see with just your eyes and your optics, then meet me in the back yard…

Monday, April 9 – Tonight let’s take a journey towards the 25th brightest star in the night sky – 1.3 magnitude, Alpha Leonis. Regulus, known as “The Little King,” is the brightest star in Leo. At 77 light-years away, this star is considered a “dwarf” despite shining with a visible light almost 150 times that of Sol. The orange-red giant Arcturus and the blue white “dwarf” Regulus both share a common absolute magnitude very close to 0. The reason the two stars shine with a similar intrinsic brightness – despite widely different physical sizes – is Regulus’ photosphere is more than twice as hot (12,000 C) as Arcturus. While observing Regulus, look for a distant companion of magnitude 8.5. Normally low powers would best concentrate the companion’s light, but try a variety of magnifications to help improve contrast. For those with large aperture scopes, look for a 13.1 magnitude “companion’s companion” a little more than 2 arc seconds away!

Tuesday, April 10 – Be sure to get up before dawn to enjoy the Virginid meteor shower. The radiant point will be near Gamma in the bowl of Virgo. The fall rate of 20 per hour is above average for meteor showers, and with the Moon partially out of the equation this morning, you’re in for a treat!

Tonight, let’s have a look at Arcturus – a star whose distance from the Earth (10 parsecs) and radial velocity (less than 200 meters per second) can almost be considered a benchmark. By skydark you will see 0.2 magnitude, Arcturus – the brightest star in Bootes and 4th brightest star in the night sky – some 30 degrees above the eastern horizon. Apparent to the eye is Arcturus’ orange color. Because a star’s intrinsic luminosity relates to its apparent brightness and distance, Arcturus’ absolute magnitude is almost precisely the same as its apparent magnitude. Just because Arcturus’ radial velocity is nearly zero doesn’t mean it isn’t on the move relative to our Sun. Arcturus is now almost as close as it will ever get and its large proper motion – perpendicular to our line of sight – exceeds 125 kilometers per second. Every 100 years Arcturus moves almost 1 degree across the sky!

Since you’ve looked at a red star, why not look at a red planet before you call it a night? Mars is still making a wonderful apparition. Have you noticed it dimming even more? Right now it should be about magnitude -0.5. You may have noticed something else about Mars in the eyepiece, too… It’s getting smaller!

Wednesday, April 11 – Today is the birthday of William Wallace Campbell. Born in 1862, Campbell went on to become the leader of stellar motion and radial velocity studies. He was the director of Lick Observatory from 1901 to 1930, and also served as president of the University of California and the National Academy of Sciences. Also born on this day – but in 1901 – was Donald H. Menzel – assistant astronomer at Lick Observatory. Menzel became Director of Harvard Observatory, an expert on the Sun’s coronosphere and held a genuine belief in the extraterrestrial nature of UFOs. Today in 1960, the first radio search for extraterrestrial civilizations was started by Frank Drake (Project Ozma). In 1986, Halley’s Comet closed within 65 million kilometers of the Earth – as close as it would get.

Tonight, why don’t we honor Campbell’s work as we try taking a look at a variable ourselves? RT (star 48) Aurigae is a bright cephid that is located roughly halfway between Epsilon Geminorum and Theta Aurigae. This perfect example of a pulsating star follows a precise timetable of 3.728 days and fluxes by close to one magnitude.

Thursday, April 12 – Today in 1961, Yuri Gagarin made one full orbit of the Earth aboard Vostok 1, while also becoming the first human in space. Also today (in 1981) Columbia became the first Space Shuttle to launch.

Break out the telescope tonight and launch your way towards Iota Cancri – a fine wide disparate double of magnitudes 4.0 and 6.6 separated by some 30 arc seconds. This true binary is so distant from one another that they take over 60,000 years to complete a single orbit around their common center of gravity! Located slightly less than a fist’s width due north of M44, this pair is about 300 light years distant. Both stars shine with a light considerably brighter than our Sun and observers may note a subtle gold and pale blue color contrast between them.

Friday, April 13 – With no early evening Moon to contend with, this is a fine opportunity to have a look at a group of galaxies between Leo’s paws. Start at Regulus and look due east toward Iota Leonis. Halfway between the two (less than a fist from Regulus) and two finger-widths northeast of Rho Leonis, you’ll encounter Messier Galaxies M95 (Right Ascension: 10 : 44.0 – Declination: +11 : 42) and M96 (Right Ascension: 10 : 46.8 – Declination: +11 : 49) – both within the same low power field of view. At magnitude 9.2, the brighter – and slightly rounder – M96 lies northeast of 9.7 magnitude, M95. Pierre Mechain discovered both galaxies on March 20, 1781 and Messier added them to his catalog 4 days later. These two galaxies are two of the brightest members of the Leo I galaxy group located some 38 million light-years away.

To see another Messier member of the Leo I group, center on M96 and shift the galaxy south. From the north side of the low power field, the 9.3 magnitude galaxy M105 (Right Ascension: 10 : 47.8 – Declination: +12 : 35), nearby 10th magnitude NGC 3384 (Right Ascension: 10 : 48.3 – Declination: +12 : 38), and 12th magnitude NGC 3389 (Right Ascension: 10 : 48.5 – Declination: +12 : 32) will come into view. M105 was discovered by Mechain on the night Messier catalogued M95 and 96 but was not formally added to Messier’s catalog. Based on Mechain’s observing notes, Helen Sawyer Hogg added it to Messier’s list in 1947 – along with galaxy M106 and globular cluster M107. Mechain failed to notice M105’s bright neighboring galaxy – NGC 3384. NGC 3384 is actually slightly brighter than the faintest Messier discovered – M91.

We’re not done yet! If you center on M105 and shift due north less than a degree and a half you will encounter 10th magnitude NGC 3377 (Right Ascension: 10 : 47.7 – Declination: +13 : 59) – a small elongated galaxy with a stellar core. There are a dozen galaxies visible to moderate amateur instruments (through magnitude 12) in the Leo I region of the sky!

Saturday, April 14 – Today is the birthday of Christian Huygens. Born in 1629, the Dutch scientist went on to become one of the leaders in his field during the 17th century. Among his achievements were promoting the wave theory of light, patenting the pendulum clock, and improving the optics of telescopes by inventing a new type eyepiece and reducing false color through increasing the focal length of refractor telescopes. Huygens was the first to discover Saturn’s rings and largest satellite – Titan. Of the rings, Huygens said, “Saturn: encircled by a ring, thin and flat, nowhere touching, and inclined to the ecliptic.”

Wanna’ check Saturn out? It will be rising in the constellation of Virgo not long after the sky begins to turn dark. If you’re not sure of which “star” it is, just wait for awhile and you’ll find it about a fistwidth northwest of bright, blue/white Spica. Be sure to check out the ring system! Right now they have a very nice southern tilt which will allow you a great view of the shadow of the planet on the rings – and the shadow of the rings on the planet. If the atmosphere will allow, power up! Something you may never have thought of looking for could be happening… Can you see the planet’s edge through the Cassini division? Be sure to look for wide orbiting Titan and some of Saturn’s smaller moons slipping around the ring edges.

Tonight our challenge is also planetary – but it’s the planetary nebula – the “Ghost of Jupiter”. Begin by identifying the constellation of Hydra. Starting at Alpha Hydrae, head east about a fist’s width to find Lambda within a field of nearby fainter stars. Continue less than a fist southeast and locate Mu. You’ll find the “Ghost of Jupiter” (NGC 3242) lurking in the dark less than a finger-width due south. At magnitude 9, the NGC 3242 (Right Ascension: 10 : 24.8 – Declination: -18 : 38) gives a strikingly blue-green appearance in even small scopes – despite being more than 1500 light years away.

Sunday, April 15 – Tonight keep a watch for the “April Fireballs.” This unusual name has been given to what may be a branch of the complex Virginid stream which began earlier in the week. The absolute radiant of the stream is unclear, but most of its long tails will point back toward southeastern skies. These bright bolides can possibly arrive in a flurry – depending on how much Jupiter’s gravity has perturbed the meteoroid stream. Even if you only see one tonight, keep a watch in the days ahead. The time for “April Fireballs” lasts for two weeks. Just seeing one of these brilliant streaks will put a smile on your face!

And if you can’t take your eyes off Leo, then there’s good reason. The combination of Theta Leonis, Regulus and Mars certainly calls attention to itself!

While we’re out, let’s journey this evening towards another lovely multiple system as we explore Beta Monocerotis. Located about a fist width northwest of Sirius, Beta is one of the finest true triple systems for the small telescope. At low power, the 450 light year distant white primary will show the blue B and C stars to the southeast. If skies are stable, up the magnification to split the E/W oriented pair. All three stars are within a magnitude of each other and make Beta one of the finest sights for late winter skies.

If you hadn’t noticed, Saturn is at opposition tonight, meaning it will be viewable from dusk until dawn. Be sure to check out the “Ring King” – but wait until it has risen well above the lower atmosphere disturbance for a superior view!

Until next week, I wish you clear and steady skies!

March 30, 2012December 23, 2015 by Jason Major

Postcards From Saturn

Saturn's second-largest moon Rhea, in front of the rings and a blurred Epimetheus (or Janus) whizzing behind. Acquired March 29, 2012.

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Over the past few days NASA’s Cassini spacecraft has performed flybys of several of Saturn’s moons. From the ostentatious Enceladus with its icy geysers to the rugged relief of Rhea, the sharp peaks of Dione’s frigid craters and even diminutive Janus, Cassini has once again returned a stack of stunning views from the Saturnian system, nearly 815 million miles from home.

Check out some of the images, and wish you were there!

N00185316 — 110-mile (177-km) -wide Janus in front of Saturn's night side.

N00185283 — A crescent-lit Enceladus shows off its jets. (South is up.)

N00185291 — Enceladus' fractured surface is some of the most reflective terrain in the Solar System.

Rhea Mimas 3-29-12 — Wide-angle view of Rhea, Saturn and Mimas

And here’s a color-composite of Janus I assembled from three raw images taken in ultraviolet, green and infrared color channels. The results were tweaked to make it a little more true-color as what we might see with our limited human vision:

Janus 3-27-12 — Color composite of Janus in front of Saturn, made from raw images taken in UV, green and IR color filters. (NASA/JPL/SSI/J. Major)

“Though we’ve been in orbit around Saturn for nearly 8 years now, we still continue to image these moons for mapping purposes and, in the case of Enceladus, to learn as much as we can about its famous jets and the subterranean, organic-rich, salty, liquid water chamber from which we believe they erupt.”

– Carolyn Porco, Cassini Imaging Team leader

For more images from Cassini, check out JPL’s mission site and the CICLOPS imaging lab site here.

Image credits: NASA/JPL/Space Science Institute.

March 28, 2012December 23, 2015 by Jason Major

“Snowing Microbes” On Saturn’s Moon?

Cassini image of Enceladus from Dec. 2010 (NASA/JPL/SSI)

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Enceladus, Saturn’s 318-mile-wide moon that’s become famous for its ice-spraying southern jets, is on astronomers’ short list of places in our own solar system where extraterrestrial life could be hiding — and NASA’s Cassini spacecraft is in just the right place to try and sniff it out.

On March 27, Cassini came within 46 miles (74 km) of Enceladus’ south pole, the region where the moon’s many active water-ice jets originate from. This was Cassini’s closest pass yet over the southern pole, allowing the spacecraft to use its ion and neutral mass spectrometer — as well as its plasma spectrometer, recently returned to service — to taste the icy spray emanating from deep fissures called “tiger stripes” that scar Enceladus’ surface.

(Fly along with Cassini toward Enceladus’ jets here.)

“More than 90 jets of all sizes near Enceladus’s south pole are spraying water vapor, icy particles, and organic compounds all over the place,” said Carolyn Porco, planetary scientist and Cassini Imaging science team leader. “Cassini has flown several times now through this spray and has tasted it. And we have found that aside from water and organic material, there is salt in the icy particles. The salinity is the same as that of Earth’s oceans.”

In addition to water, salt and organics, there is also a surprising amount of heat — heat generated in part by tidal friction, helping keep Enceladus’ underground water reserves liquid.

“If you add up all the heat, 16 gigawatts of thermal energy are coming out of those cracks,” Porco said.

This creates, in effect, a so-called “Goldilocks zone” of potential habitability orbiting around Saturn… a zone that Cassini has easy access to.

“It’s erupting out into space where we can sample it. It sounds crazy but it could be snowing microbes on the surface of this little world,” Porco said. “In the end, it’s the most promising place I know of for an astrobiology search. We don’t even need to go scratching around on the surface. We can fly through the plume and sample it. Or we can land on the surface, look up and stick our tongues out. And voilà…we have what we came for.”

enceladus_stripe_11-30-10-1 — Cassini's view down into a jetting "tiger stripe" in August 2010

Cassini’s latest results — and images! — from the flyby should be landing on Earth any time now. Stay tuned to Universe Today for more updates on Cassini and Enceladus.