Weekend SkyWatcher’s Forecast: January 30 – February 1, 2009

Greetings, fellow SkyWatchers! The Moon is back again, but what a terrific target for winter studies. Why not get out your binoculars and telescopes as we take a look at strange and unusual places like the Serpent Sea, the Marsh of Sleep and the Lakes of Time, Death and Dreams? If you haven’t wished upon a star lately, then there’s a serious reason to take a look at Sirius this weekend! Step outside in the dark with me where we’ll explore a little history, a little mystery, and just plain have us some fun…

Friday, January 30, 2009 – Tonight’s early evening Moon is high enough to warrant study. During the last lunar cycle, we reviewed maria large enough to be seen unaided, but many more can be revealed telescopically. Magnify the Crisium region and let’s look around. Along the eastern side near the lunar limb is Mare Marginis, whose position between the nearside and farside will never allow us to see more than a thin gray line. Thanks to the lunar orbiters, we know it has an irregular border and shallow lava fill, which lead scientists to believe Marginus wasn’t created from an impact. Located southeast is Mare Undarum , the ‘‘Sea of Waves.’’ This highly elevated part of the Crisium basin is about the size of Massachusetts, and it probably filled with lava around the time of the Imbrium impact. Northeast, and separated by a mountain range, is Mare Anguis, or the ‘‘Serpent Sea.’’ This Vermont-sized area of lunar landscape formed differently and may be home to a vast number of lava tubes.

crisium_region

Now look to Crisium’s northwest for a new feature, Lacus Bonitatis , or the ‘‘Lake of Goodness.’’ With features similar to those of maria, this small, irregularly shaped area has as much ‘‘coastline’’ as the Black Sea! Further south is Palus Somni, the ‘‘Marsh of Sleep.’’ This curious feature is an upland area. Relatively flat—but very uneven—its high albedo (surface reflectivity) makes it a rewarding study. Last on tonight’s tour is Sinus Concordiae , the ‘‘Bay of Harmony.’’ Essentially part of the maria that spawned it, this inlet leads toward higher ground. Concordiae’s small bay is roughly the size of Pedro Bank in Jamaica. Like its earthly counterpart, it may have mountain peaks that are just barely covered – but by lava flow, not seawater. Be sure to list your evening’s observations in your lunar notes. We’ll return in the months ahead here for more!

‘‘Everything has a natural explanation. The moon is not a god, but a great rock.’’ — Anaxagoras (475 BC)

hamSaturday, January 31, 2009 – What a busy date in astronomy history! In 1958 the United States. launched its first satellite – Explorer 1 – which discovered the bands of radiation now referred to as the Van Allen Belts . In 1961 the Mercury-Redstone 2 launched, carrying Ham the chimpanzee to fame. Cabin pressure failed during the suborbital flight, but inside his pressure suit, Ham remained safe and performed his tasks with a reaction time only a half second slower than on the ground, proving primates could function in space! (And a few years later, astronauts started drinking and shooting at each other, proving that humans could function like primates.) Ham lived for another 17 years, and the celebrated chimp gave many performances – even guest starring in movies!

Luna 9 was launched in 1962 and 72 hours after its launch became the first craft to successfully touch down on the Moon and broadcast television from Oceanus Procellarum . Even Apollo 14 was Luna-bound today in 1971! Alvan Graham Clark , Jr, made history at the eyepiece on this date in 1862. While watching Sirius and testing an 18″ refractor his family built, Clark uncovered the intense star’s faint companion – Sirius B. Friedrich Bessel had proposed its existence back in 1844, but this was the first visual confirmation.

sirius_chumack

Try your own hand at the ‘‘Scorching One.’’ Alpha Canis Majoris has an amazing magnitude of -1.42. Next to Alpha Centauri , 8.7 light-year distant Sirius is the closest visual star, but it’s not standing still. Part of the Ursa Major moving stream, Sirius has changed position by one and half times the apparent width of the Moon in just 2,000 years! Telescopically, this main-sequence gem is dazzling white, tinged with blue and diffracts a rainbow of colors. For many of us, beautiful iridescence is all we’ll ever see, but a small telescope (114-150mm) under perfectly steady skies will reveal the secretive companion. In 20 years it will reach maximum separation of 11.500, so keep watching to Sirius’ southeast when you observe – perhaps you’ll spot B!

berknerSunday, February 1, 2009 – On this day we celebrate the 1905 birth of Lloyd Berkner, the first person to measure Earth’s ionosphere. His work with radar led to an understanding of radio wave propagation. He also served as administrator at Green Bank National Radio Astronomy Observatory. For his achievements in space science, NASA awarded Berkner the Distinguished Public Service Medal.

The broad crescent Moon dominates the early evening sky. Tonight we’ll explore new features as we start in the lunar north with Mare Humboldtianum spanning 350 kilometers, this inconspicuous multi-ringed feature depends on libration for best views.

hope

Further south along the limb is Lacus Spei (the Lake of Hope), a diminutive feature so small it could be crossed at walking speed in 10 hours! West of Humboldtianum and Spei is a pair of lighter areas devoid of features— Lacus Temporis (the Lake of Time). These two small overlapping basins were filled by the same lava flow, thus forming this small mare. How long to walk across Temporis? Twice as much ‘‘Time’’ as ‘‘Hope’’!

Relocate Mare Frigoris (the Cold Sea) and look south along the terminator for Lacus Mortis (the Lake of Death) and its counterpart Lacus Somniorum (the Lake of Dreams). Is there a connection here? You betcha! These two basin areas were filled from a basaltic flow, which might have united them, but a small mountain range kept them apart.

‘‘There is something haunting in the light of the Moon; it has all the dispassionateness of a disembodied soul, and something of its inconceivable mystery.’’ –Joseph Conrad

By the way, we believe Werner Heisenberg died on this day in 1976, but no one is certain.

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

This week’s awesome images are: The Crisium Region (credit—Greg Konkel), Ham
the Chimpanzee (credit—NASA), Sirius (credit—John Chumack), Lloyd Berkner (public image) and Hope, Time, Death, and Dreams (credit—Greg Konkel). We thank you so much for sharing your splendid talents with us!

Moon, Venus and Jupiter Dazzle on December 1

[/caption]

Are you ready for some spectacular sky scenery tonight? Then keep your fingers crossed for clear weather as the slender crescent Moon, Venus and Jupiter provide one of the finest sky shows we’ve seen all year – a conjunction in the west to dazzle the eye and boggle the brain! But just exactly why does seeing bright planets draw together command our attention? Step inside and let’s find out…

“Your eye is like a digital camera,” explains Dr. Stuart Hiroyasu, O.D., of Bishop, California. “There’s a lens in front to focus the light, and a photo-array behind the lens to capture the image. The photo-array in your eye is called the retina. It’s made of rods and cones, the fleshy organic equivalent of electronic pixels.” Near the center of the retina lies the fovea, a patch of tissue 1.5 millimeters wide where cones are extra-densely packed. “Whatever you see with the fovea, you see in high-definition,” he says. The fovea is critical to reading, driving, watching television. The fovea has the brain’s attention. The field of view of the fovea is only about five degrees wide.” Tonight, Venus, Jupiter and the crescent Moon will all fit together inside that narrow angle, signaling to the brain, “this is worth watching!”

When it comes to our eyes, almost every photoreceptor has one ganglion cell receiving data in the fovea. That means there’s almost no data loss and the absence of blood vessels in the area means almost no loss of light either. There is direct passage to our receptors – an amazing 50% of the visual cortex in the brain! Since the fovea doesn’t have rods, it isn’t sensitive to dim lights. That’s another reason why the conjunctions are more attractive than the surrounding starfields. Astronomers know a lot about the fovea for a good reason: it’s is why we learn to use averted vision. We avoid the fovea when observing very dim objects in the eyepiece.

Let’s pretend we’re a photoreceptor. If a light were to strike us, we’d be “on” – recording away. If we were a ganglion cell, the light really wouldn’t do much of anything. However, the biological recorder would have responded to a pinpoint of light, a ring of light, or a light with a dark edge to it. Why? Light in general just simply doesn’t excite the ganglion, but it does wake up the neighbor cells. A small spot of light makes the ganglion go crazy, but the neighbors don’t pay much attention. However, a ring of light makes the neighbors go nuts and the ganglion turns off. It’s all a very complicated response to a simple scene, but still fun to understand why we are compelled to look!

Many of us have been watching the spectacle draw closer over the last several days. How many of you have seen the Venus and Jupiter pair appear one over the top of each other – looking almost like a distant tower with bright lights? What we’ve been observing is Kepler’s Laws of Planetary Motion in action – and it’s a great way to familiarize yourself with celestial mechanics. What’s happening tonight is called a conjunction. This is a term used in positional astronomy which means two (or more) celestial bodies appear near one another in the sky. Sometimes the event is also called an appulse.

No matter what you call it, what you’ll see tonight is a worldwide happening and will look hauntingly like a “happy face” painted on the early evening sky. Don’t miss it!

Our deepest appreciation goes to Shevill Mathers for his dedication in getting this shot to share with us, and all the rest of the great astrophotographers at Northern Galactic and Southern Galactic who have also gave it their best shot! There can be only one…

See Doomed Spacecraft Before Its Fiery Demise

[/caption]

The Jules Verne Automated Transfer Vehicle (ATV) has done its duty – it even went above and beyond its expected capabilities. But the end is nigh, and soon, on September 29 the ATV will become a fireball and burn up in the Earth’s atmosphere, never to be seen again. But before it does, people in North America and Europe have the perfect opportunity to see it sail overhead this weekend in its low Earth orbit, and according to Spaceweather.com, the ATV will glow about a brightly as the North Star, Polaris. To find out when and where to look for the ATV in the evening or early morning skies, check out Spaceweather.com’s great satellite tracking webpage. Just plug in your zip code and you’ll be able to get tracking information for all the satellites that will be visible for the next few days. Also, Heavens Above is a great site to find tracking information, as well. So get out there and bid Jules Verne adieu. Here’s some of the great things the ATV accomplished while on orbit at the ISS, and a movie of its undocking too…


The Jules Verne spent five months docked to the space station where it delivered supplies (and fun things like a manuscript written by its namesake.) The supply ship turned into a tug boat when its engines were fired up to help the ISS avoid a piece of space junk. It also served as an impromptu bedroom for the space station crew.

When will the next ATV fly? Sometime in 2010, and the name for that ship has not yet been revealed. It will follow the debut of another space station cargo ship, Japan’s H-2A Transfer Vehicle, set for next year.

Here’s a movie of the Jules Verne undocking from the ISS.

Source: Spaceweather.com

WeekEnd SkyWatcher’s Forecast: July 4 – 6, 2008

Greetings, fellow SkyWatchers! If you’re enjoying a holiday weekend where you live, then start the fireworks off as we begin by remembering Deep Impact and journey towards a nearby star approaching the supernova phase. As things heat up towards one of the most spectacular conjunctions of the year, we’ll also take a look at another globular cluster study, lunar features and a binocular deep sky treat! Are you ready to step in the realm of a Barnard dark nebula? The grab your optics and let’s head out into the night…

Friday, July 4 – On this date in 2005, the Deep Impact mission entered the history books as its probe impacted Comet Tempel 1 successfully. The spacecraft relayed back to Earth a wealth of information about the material released from the surface. Thanks to this incredible mission (a collaboration between JPL, the University of Maryland, and Ball Aerospace Technologies), we’ve learned much more about the nature of comets and the protosolar nebula in which they formed.

This date in history also marks the 1947 founding of the Astronomical League – a worldwide organization with almost 15,000 members!

And did you know that celestial fireworks occurred in 1054, also on this day? It is believed the bright supernova recorded by Chinese astronomers happened at this point in history, and today we know its remnants as the Crab Nebula (M1).

Palomar Observatory, courtesy of CaltechBut could such an event happen again in our own celestial “backyard?” Look no further than HR 8210 (RA 21 26 26 Dec +19 22 32). It may be nothing more than a white dwarf star hiding out in late night Capricornus, but it’s a star that’s almost run out of fuel. This rather ordinary binary system has a companion white dwarf star that’s 1.15 times the mass of our Sun. As the companion also expends its fuel, it will add mass to HR 8210 and push it over the Chandrasekhar limit – the point of no return in mass. This will someday result in a supernova event located only 150 light-years away from our solar system…

And that’s 50 light-years too close for comfort!

470 light-years away in the Gould Belt, and roughly 1.5 million years ago, a similarly massive star exploded in the Upper Scorpius association. No longer able to fuel its mass, it unleashed a supernova event which left its evidence as a layer of iron here on Earth, and may have caused a certain amount of biological extinction when its gamma rays directly affected our ozone layer.

Take a long look at Antares tonight – for it is part of that association of stars and is no doubt also a star poised on the edge of extinction. At a safe distance of 500 light-years, you’ll find this pulsating red variable equally fascinating to the eye as well as to the telescope. Unlike HD 8210, Alpha Scorpii also has a companion which can be revealed to small telescopes under steady conditions. Discovered on April 13, 1819 during a lunar occultation, this 6.5 magnitude green companion isn’t the easiest to split from such a bright primary – but it’s certainly fun to try! And the best is yet to come, because Antares will be occulted again in a matter of days…

Saturday, July 5– Tonight the Moon has returned in a position to favor a bit of study. Start by checking IOTA information for a possible visible occultation of Regulus, and also look for Saturn quite nearby as the slender crescent graces the early evening skies.

Although poor position makes study difficult during the first few lunar days, be sure to look for the ancient impact crater Vendelinus just slightly south of central. Spanning approximately 150 kilometers in diameter and with walls reaching up to 4400 meters in height, lava flow has long ago eradicated any interior features. Its old walls give mute testimony to later impact events, which you can see when viewing crater Holden on the south shore; much larger Lame on the northeast edge; and sharp Lohse northwest. Mark your challenge list!

For all observers, let’s take a closer look at the fascinating constellation of Lupus southwest of brilliant Antares. While more northern latitudes will see roughly half of this constellation, it sits well at this time of year for those in the south. So why bother?

Cutting through our Milky Way galaxy at a rough angle of about 18 degrees is a disc-shaped zone called Gould’s Belt. Lupus is part of this area whose perimeter contains star forming regions which came to life about 30 million years ago when a huge molecular cloud of dust and gas was compressed – much like in the Orion area. In Lupus we find Gould’s Belt extending above the plane of the Milky Way!

Palomar Observatory, courtesy of CaltechReturn again to the beautiful Theta and head around five degrees west for NGC 5986 (RA 15 46 03 Dec 37 47 10), a 7th magnitude globular cluster which can be spotted with binoculars with good conditions. While this Class VII cluster is not particularly dense, many of its individual stars can be resolved in a small telescope.

Now sweep the area north of NGC 5986 (RA 17 57 06 Dec 37 05 00) and tell me what you see. That’s right! Nothing. This is dark nebula B 288 – a cloud of dark, obscuring dust which blocks incoming starlight. Look carefully at the stars you can see and you’ll notice they appear quite red. Thanks to B 288, much of their emitted light is absorbed by this region, providing us with a pretty incredible on-the-edge view of something you can’t see – a Barnard dark nebula.

NASASunday, July 6 – Celestial scenery alert! SkyWatchers… Mark your calendar and be sure to make this date with the western skyline as sunset marks one of the most picturesque views of the year! Regulus, Mars and Saturn will all dance with the da Vinci Moon. No special equipment is needed to see this event, and thanks to Leonardo da Vinci we can see the ghostly effect on the Moon as quite logical. He was the first to theorize that sunlight was reflecting off the Earth and illuminating the portion of the Moon not lit by the Sun. We more commonly refer to this as “Earthshine” – but no matter how scientific the explanations are for this phenomena, its appearance remains beautiful.

Today in 1687, Isaac Newton’s monumental Principia was published by the Royal Society with the help of Edmund Halley. Although Newton was indeed a very strange man with a highly checkered history, one of the keys to Newton’s work with the theory of gravity was the idea that one body could attract another across the expanse of space.

Now let’s have a look at some things gravitationally bound as we start at Eta Lupi, a fine double star which can even be resolved with binoculars. Look for the 3rd magnitude primary and 8th magnitude secondary separated by a wide 15″. You’ll find it by starting at Antares and heading due south two binocular fields to center on bright H and N Scorpii – then one binocular field southwest (RA 16 00 07 Dec 38 23 48).

Palomar Observatory, courtesy of CaltechWhen you are done, hop another roughly five degrees southeast (RA 16 25 18 Dec 40 39 00) to encounter the fine open cluster NGC 6124. Discovered by Lacaille and known to him as object I.8, this 5th magnitude open cluster is also known as Dunlop 514, as well as Melotte 145 and Collinder 301. Situated about 19 light-years away, it will show as a fine, round, faint spray of stars to binoculars and be resolved into about 100 stellar members to larger telescopes. While NGC 6124 is on the low side for northern observers, it’s worth the wait for it to hit its best position. Be sure to mark your notes, because this delightful galactic cluster is a Caldwell object and a southern skies binocular reward!

Wishing you an awesome weekend…

This week’s photos are courtesy of: Deep Impact Mission – Credit: JPL/NASA, HR 8210 – Credit: Palomar Observatory courtesy of Caltech, NGC 5986 – Credit: Palomar Observatory courtesy of Caltech, Da Vinci Moon – Credit: NASA and NGC 6124 – Credit: Palomar Observatory courtesy of Caltech.

Binocular Astronomy: Get Sirius!

m50y.thumbnail.jpg

For urban and suburban dwellers, practicing binocular astronomy can sometimes be discouraging because of the lack of faint marker stars to help locate deep sky objects. Right now, early evening dark skies are the perfect opportunity to spot the brightest star in the night sky – Sirius – and let it lead you on to some deep sky gems! So print off this article, grab your binoculars and a good friend and get outside!

Just after sky dark, head outside and look basically south for the “Scorching One”. Even if you don’t use binoculars, this 8.6 distant light year beauty sparkles and twinkles like a true diamond. Even though it’s only the atmosphere which causes the effect, Sirius’ beauty has been noted throughout ancient history in both culture and mythology. Small wonder, it’s twice as large as our own Sun and 25 times more luminous! One of the earliest star charts done by Ptolemy recorded Sirius’ position and in 1676 Edmund Halley noted its movement. While today we understand that stars with large proper motion mean they are closer to us than further away, it was definitely an eye-opening experience for early astronomers.

Now, open your eyes wide by using binoculars of any size and center on Sirius. Move slowly south about one average binocular field until you see a compression of stars. Congratulations! You’ve just spotted Messier Object 41. As incredible as it may seem, this bright cluster of stars may have also been noticed by Aristotle as far back as 325 BC… without modern optics! Spanning about 25 light years across, there are about 100 stars which are true members of the cluster. if you thought Sirius was bright, then take a close look for a reddish central star. It’s 280 times brighter yet than Sirius! Thank heavens it’s about 2,300 light years away or there would be no such thing as a “dark sky”.

Now head back to Sirius and let’s take a hop Northeast just a little more than two binocular fields. Do you see that small heart-shaped collection of stars? It’s Messier Object 50. Although this galactic cluster contains about twice as many stars as M41, they are so faint they are difficult to see from light polluted skies. If you have larger binoculars, you can probably even spot some color differences between members.

Let’s get Sirius again. This time we’re headed almost due east about another two binocular fields. Messier Object 47 is quite bright by comparison, and with good reason; it’s much closer than the other two clusters. This time we’re only looking about 1,600 light years away. Like its other two star-studded companions, it’s about the same age, but has fewer stars. This particular cluster curiosity was an instance where Charles Messier messed up. He recorded its position wrong! For now? Have a look around. These bright clusters are easily seen from most locations and all you have to do is…

Binocular astronomy: Get Sirius!