Observing Archives

September 25, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – September 25-27, 2009

Greetings, fellow SkyWatchers! We’re back and recovered from a star party – and what an awesome time! (I felt like Dorothy in the “Land of Oz”… Comets and meteors and galaxies… oh, my!) I am sure that many of you also enjoyed a great time and although the Moon is back on this weekend scene, why not celebrate it? Just how long has it been since you’ve kicked back and relaxed with a little lunacy in your scope? Pick up a sketchbook, or get creative with a camera! Lunatic fringe? I know you’re out there. And I’ll see you inside…

Friday, September 25, 2009 – Today we celebrate the 1625 birth on this date of Ole (Christensen) Romer. Romer, by timing Jupiter’s moons being eclipsed, was the first to prove that light had a finite speed. Let’s walk upon our own Moon this evening as we take a look at sunrise over one of the most often studied and mysterious of all craters, Plato. Located on the northern edge of Mare Imbrium, and spanning 95 kilometers in diameter, Class IV Plato is simply a feature that all lunar observers check because of the many reports of unusual happenings. Over the years mists, flashes of light, areas of brightness and darkness, and the appearance of small craters have become a part of Plato’s lore.

On October 9, 1945, an observer sketched and reported ‘‘a minute but brilliant flash of light’’ inside the western rim. Lunar Orbiter 4 photos later showed where a new impact may have occurred. Although Plato’s interior craterlets average between less than 1 and up to slightly more than 2 kilometers in diameter, many times they can be observed, and sometimes they cannot be seen at all under almost identical lighting conditions. No matter how many times you observe this crater, it is ever-changing and very worthy of your attention!

Saturday, September 26, 2009 – Tonight’s featured lunar crater will be located on the south shore of Mare Imbrium right where the Apennine mountain range meets the terminator. Eratosthenes is unmistakable at 58 kilometers in diameter and 375 meters deep.

Named after the ancient mathematician, geographer, and astronomer Eratosthenes, this splendid Class I crater will display a bright west wall and a deep interior, which contains its massive crater-capped central mountain reaching up to 3,570 meters high! Extending like a tail, an 80-kilometer-long mountain ridge angles away to the southwest. As beautiful as Eratosthenes appears tonight, it will fade away to total obscurity as the Moon becomes more nearly full. See if you can spot it in 5 days!

Now let’s journey to a very pretty star field as we head toward the western wingtip of Cygnus, to have a look at Theta, also known as 13 Cygni (RA 19 36 26 Dec +50 13 15). Theta is a beautiful main sequence star that is also considered by modern catalogs to be a double. For large telescopes, look for a faint (13th magnitude) companion to the west. But it’s also a wonderful optical triple! In the field with Theta to the southeast is the Mira-type variable R Cygni, which ranges in magnitude from around 7–14 in slightly less than 430 days. This pulsating red star has a really interesting history that can be found at American Association of Variable Star Observers (AAVSO) and is circumpolar for far northern observers. Check it out!

Sunday, September 27, 2009 – Today we celebrate the 1814 birth on this date of Daniel Kirkwood. In 1866, this American astronomer was the first to publish his discovery of gaps in the distances of asteroids from the Sun, the ‘‘Kirkwood Gaps.’’ Not only did he study the orbits of asteroids, but he was also the first to suggest that meteor showers were caused by orbiting debris from comets. Known as ‘‘the American Kepler,’’ Kirkwood went on to author 129 publications, including three books.

Tonight on the Moon, let’s take an in-depth look at one of the most impressive of the southern lunar features—Clavius. Although you cannot help being drawn visually to this crater, let’s start at the southern limb near the terminator and work our way up.

Your first sighting will be the large and shallow dual rings of Casatus, with its central crater, and Klaproth adjoining it. Further north is Blancanus, with its series of very small interior craters, but wait until you see Clavius. Caught on the southeast wall is Rutherford, with its central peak, and crater Porter on the northeast wall. Look between them for the deep depression labeled D. West of D you will also see three outstanding impacts: C, N, and J; CB resides between D and Porter. The southern and southwest walls are also home to many impacts, and look carefully at the floor for many, many more! Clavius has been often used as a test of a telescope’s resolving power to see just how many more craters you can find inside it. Power up and enjoy!

This week’s awesome photos are (in order of appearance): Plato area (credit—Sketch by Deirdre Kelleghan), Eratosthenes (credit—Alan Chu), Theta Cygni (credit—Palomar Observatory, courtesy of Caltech), Daniel Kirkwood (widely used public image) and Clavius (credit—Wes Higgins). We thank you so much!

September 17, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – September 18-20, 2009

Greetings, fellow SkyWatchers! It’s an awesome weekend forecast for many of us attending Fall Star Parties, and all over the world we’re looking forward to moonless nights and the fellowship with our brother and sister amateur astronomers. If you’ve never been to a star party, try the Goggle pages for information… you just might find one going on near you! In the meantime, let’s have us a “Snowball” fight, chase some galaxies and ponder double stars! I’ll see you in the night…

Friday, September 18, 2009 – One of the most interesting features of the autumn sky is how slowly the stars and constellations seem to proceed across the heavens. This is only an illusion, since skydark arrives earlier each night (after summer solstice in the Northern Hemisphere), making the progress of the constellations across the sky seems to ‘‘freeze.’’ Tonight, Capella can be seen rising to the northeast just as Antares settles southwest. Four planets—Jupiter, Pluto, Neptune, and Uranus—are still above the horizon, with Jupiter now very low to the west-southwest. Descending to the northwest is Ursa Major, the ‘‘Big Dipper.’’ Across the sky is Piscis Austrinus, and lonely but bright Fomalhaut is beginning its rise. Seven stars of the first magnitude now grace the heavens. Against this backdrop, one of the darkest skies of the month is now upon us. It’s the New Moon…

Let’s have a look at another fine planetary nebula—NGC 7662. At 9 magnitude, this one is more commonly known as the ‘‘Blue Snowball’’ and can be found about three finger-widths east of Omicron Andromedae, or a little less than a handspan northwest of Alpha Pegasi (RA 23 25 54 Dec +42 32 06).

Similar in size to M57, even low power with a small scope easily reveals the planetary nature of this very fine study. Power up and you’ll discover that the annulus of this roughly circular planetary is definitely brighter inside than out. Large telescopes will highlight NGC 7662’s blue coloration and reveal a bright inner globe surrounded by a faint outer ring.

Saturday, September 19, 2009 – On this date in 1848, William Boyd was observing Saturn and discovered the planet’s eighth moon, Hyperion. If you’re out before sunset, some lucky stargazers are going to discover that the slender crescent Moon is about to occult Mercury! Check the Resources in this book and IOTA for locations and dates. Then check them both out in binoculars!

Would you like to try for another pair? Then wait until the skies are fully dark and head north for a galaxy and cluster pairing—NGC 6946 (RA 20 34 51 Dec +60 09 18) and NGC 6939 (RA 20 31 30
Dec +60 39 42).

Located in western Cepheus, you’ll find them about a finger-width southwest of Eta.

Discovered by William Herschel on September 9, 1798, 10 million-light-year-distant face-on spiral NGC 6946 spreads itself pretty thin in modest instruments. Lacking a bright core, this oval mist orients southwest to northeast. Larger telescopes will reveal traces of rotating spiral arms, especially in the southwest. This galaxy would appear extraordinary if we weren’t looking through Milky Way obscuration to view it! Through smaller scopes, northwestern open cluster NGC 6939 appears like a tight little formation of 11th and 12th magnitude stars similar in pattern to a very small M11. It resolves well in larger scopes.

Sunday, September 20, 2009 – Today we recognize the passing of cosmonaut Gherman S. Titov in 2000; Titov was not only the second human in space but also the youngest! Perhaps when he was orbiting Earth in Vostok 2 he had a chance to see the Moon. Why don’t we join him? Tonight, your lunar mission is to journey to the edge of the east limb and slightly south of central to identify crater Humboldt. Seen on the curve, this roughly 200-kilometer-wide crater holds a wealth of geographical details. Its flat, cracked floor has central peaks and a small mountain range, as well as a radial Rille structure. If libration and steadiness of skies are in your favor, power up and look for dark pyroclastic areas and a concentric inner crater.

Now, let’s have a look at Beta and Gamma Lyrae, the lower two stars in the ‘‘Harp.’’ Beta is actually a quick-changing variable, which drops to less than half the brightness of Gamma in about 12 days. For a few days, the pair will seem of almost equal brightness, and then you will notice the star closest to Vega fade away. Beta is one of the most unusual spectroscopic stars in the sky, and it is possible that its eclipsing binary companion may be the prototype of a ‘‘collapsar’’ (yep, a black hole!), rather than a true luminous body.

Enjoy your weekend!!

This week’s awesome images (in order of appearance) are: NGC 7662 (credit—Adam Block/NOAO/AURA/NSF), NGC 6946 and NGC 6939 (credit—Palomar Observatory, courtesy of Caltech), Crater Humboldt (credit—Ricardo Borba) and Beta Lyrae (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!!

September 11, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – September 11-13, 2009

Greetings, fellow SkyWatchers! Now that the Moon is backing off the early evening skies, it’s time to enjoy some more elusive targets – like ones that are gone in the “blink” of an eye, or “veiled” in mystery… While you might think all of these are telescope-only domain, if you’ve got dark skies and eyes, you might be surprised! Why not take some time this weekend to get out your telescopes or binoculars and have some fun? There’s some tasty summer treats waiting on you, and I’ll see you in the backyard…

Friday, September 11, 2009 – Today we celebrate the birthday of Sir James Jeans. Born in 1877 on this date, English-born Jeans was an astronomical theoretician. At the beginning of the twentieth century, Jeans worked out the fundamentals of the process of gravitational collapse. This was an important contribution to the understanding of the formation of solar systems, stars, and galaxies.

While we are studying some of the summer’s finest objects, we’d be remiss if we didn’t look at another cosmic curiosity—the ‘‘Blinking Planetary.’’ Located a couple of degrees east of visible star Theta Cygni, and in the same lower power field as 16 Cygni (RA 19 44 48 Dec +50 31 30), it is formally known as NGC 6826.

Viewable in even small telescopes at mid-to-high power, you’ll learn very quickly how its name came about. When you look directly at it, you can only see the central 9th magnitude star. Now, look away. Focus your attention on visual double 16 Cygni. See that? When you avert, the nebula itself is visible. This is actually a trick of the eye. The central portion of our vision is more sensitive to detail and will only see the central star. At the edge of our vision, we are more likely to see dim light, and the planetary nebula appears. Located around 2,000 light-years from our Solar System, it doesn’t matter if the Blinking Planetary is a trick of the eye or not. . .because it’s cool! Also known as Herschel IV.73 and Caldwell object 16, this tiny planetary shows an abundance of carbon and dust pockets in its structure. It skyrocketed to fame when viewed by the Hubble Space Telescope (HST), which revealed the mysterious red ‘‘FLIERS,’’ whose bow shocks point toward this planetary nebula instead of away
from it!

Saturday, September 12, 2009 – Today we note two births: Arthur von Auwers (1838), who calculated stellar distances; and Guillaume Le Gentil (1725), who was a frustrated Venus transit observer! Tonight, do your best not to be frustrated as we encourage those with larger binoculars and telescopes to head for a dark sky location. We are going on a quest… the quest for the holy ‘‘Veil.’’

By no means is the Veil Nebula Complex an easy one. The brightest portion, NGC 6992 (RA 20 56 20 Dec +31 41 48), can be spotted in large binoculars, and you can find it just slightly south of a central point between Epsilon and Zeta Cygni. NGC 6992 is much better in a 6″ scope, however, and low power is essential to see the long ghostly filaments that span more than a degree of sky.

About 2.5 degrees west-southwest, and incorporating star 52, is another long narrow ribbon of what may be classified as a supernova remnant. When aperture reaches the 12? range, so does the true breadth of this fascinating complex. It is possible to trace these long filaments across several fields of view. They sometimes dim and at other times widen, but like watching a surreal solar flare, you will not be able to tear your eyes away from this area. Another undesignated area lies between the two NGCs, and the whole 1,500-light-year-distant area spans over 2.5 degrees. Sometimes known as the Cygnus Loop, it’s definitely one of late summer’s finest objects.

Sunday, September 13, 2009 – Your first challenge for this morning is to check out the last quarter Moon and look for Mars nearly touching it!

On this date in 1922, the highest air temperature ever recorded at the surface of Earth occurred. The measurement was taken in Libya and burned in at a blistering 136F (58C), but did you know that the temperatures in the sunlight on the Moon are double that? If you think the surface of the Moon is a bit too warm for comfort, then know surface temperatures on Mars average only about 80F (27C) during the day!

Tonight, let’s take the time to hunt down an often overlooked globular cluster—M56. Located roughly midway between Beta Cygni and Gamma Lyrae (RA 19 15 35.50 Dec +30 11 04.2), this Class X globular was discovered by Charles Messier in 1779 on the same night he discovered a comet and was later resolved by Herschel.

At magnitude 8 and small in size, it’s a tough call for a beginner with binoculars but is a very fine telescopic object. With a general distance of 33,000 light-years, this globular resolves well with larger scopes but doesn’t show as much more than a faint, round area with small aperture. However, the beauty of the chains of stars in the field makes it quite worth the visit! While you’re there, look carefully: M56 is one of the very few objects for which the photometry of its variable stars was studied strictly with amateur telescopes. Although one bright variable had been known previously, up to a dozen more have recently been discovered. Of those, six had their variability periods determined using CCD photography and telescopes just like yours!

Until next week? Enjoy!

This week’s awesome images are (in order of appearance): Sir James Jeans (widely used public image), NGC 6826: the Blinking Planetary (credit—Hubble Space Telescope/NASA), The Veil Nebula (credit—NOAO/AURA/NSF), Mars (credit—NASA) and M56 (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

September 9, 2009December 24, 2015 by Nancy Atkinson

Great Views of the ISS and Shuttle From Earth and Space

The ISS and Discovery on Sept. 1, 2009. Credit: Paolo Beltrame

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Paolo Beltrame from Italy sent us this amazing montage of images he took of space shuttle Discovery docked to the ISS on September 1, 2009. See the incredible details visible of the space station and docked shuttle! Paolo is with the Circolo AStrofili Talmassons (Amateur Astronomers Club in Talmassons, or CAST) who have an impressive observatory (take a look at Paolo’s website). He took these selected images from a 2-minute movie taken with a TourcamPro webcam. As impressive as Paolo’s astrophotos are, however, he says his real passion is viewing the night sky with the naked eye. His motto is “Lasciate che i fotoni vengano a me!” (Let the photons come to me!) See a close up of Paolo’s best shot of the ISS/shuttle below, as well as images from other astrophotographers of Tuesday evening’s pass of the shuttle and ISS as they flew in tandem after Discovery undocked from the station on Tuesday afternoon. There’s also video from the shuttle’s flyaround.

The ISS and shuttle on Sept. 1, 2009 at 3:03 UT. Credit: Paolo Beltrame

Below is Kevin Jung’s image of the ISS and shuttle as they flew in tandem over Grand Rapids, Michigan:

Kevin made it home just in time to take this image, and he said the pair of spacecraft went just below Lyra, and you can make out some of the other things in the field, as well. Click the image to see more of Kevin’s handiwork.

And here’s my feeble attempt to image the tandem flyover from my yard in Illinois:

ISS, shuttle and a star. Credit: N. Atkinson

Can anyone guess what the star in the picture might be?

Finally, enjoy some video of the shuttle’s fly-around of the ISS following undocking. This video just shows the the shuttle due to the lack of Ku band downlink availability. Video of the station from the orbiter was not available, but we’ll post it here later if it becomes available.

September 4, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast: September 4-6, 2009

Greetings, fellow SkyWatchers! Ah, yes… Full Moon. Are you ready to howl? If you didn’t get a chance to watch the galiean moons do their dance last weekend, then be sure to catch the awesome video you’ll find inside! In the meantime, keep your ears alert for the rise of tonight’s “Full Corn Moon” and check out the Omicron gems. As the skies get darker, the Herschel challenges warm up – so dust off your optics and I’ll see you in the backyard…

Friday, September 4, 2009 – It’s a Full Moon tonight. Many cultures refer to this one in particular as the ‘‘Corn Moon,’’ because at this time of year most corn crops are ready for harvest. Tonight let’s harvest some bright lunar features as we trace the ray system of Tycho in the lunar south. Look for the bright points of Kepler and Aristarchus in the northwest quadrant. In the east, dazzling crater Proclus will light up the western shore of Mare Crisium. Just north of central, look for the two bright rings of Manlius and Menelaus.

Although the Moon will dominate tonight’s sky, we can still take a very unusual and beautiful journey to a bright and very colorful pair of stars known as Omicron 1 Cygni. Easily located about halfway between Alpha (Deneb) and Delta on the western side (RA 20 13 28 Dec +46 46 40), this is a pure delight in binoculars or any size telescope.

The striking gold color of 3.7-magnitude Omi 1 A is easily highlighted against the blue of its same-field companion, 5th magnitude Omi 1 B. Although this wide pairing is only an optical one, the K-type giant (A) is indeed a double star—an eclipsing variable about 150 times larger than or own Sun—and is surrounded by a gaseous corona more than double the size of the star itself. If you are using a scope, you can easily spot its blue tinted, 7th magnitude companion star about one-third the distance between the two giants. Although our true pair is some 2 billion kilometers apart, they are oriented nearly edge-on from our point of view, allowing the smaller star to be totally eclipsed during each revolution. This total eclipse lasts for 63 days and happens about every 10.4 years, but don’t stay up too late. . . We still have years to wait!

Saturday, September 5, 2009 – Tonight before the Moon commands the sky, let’s start with the brightest star in Vulpecula—Alpha. Although it is not a true binary star, it is quite attractive in the telescope, and an easy split for binoculars. Alpha itself is a 4.4-magnitude red giant, which makes a nice color contrast with the unrelated yellow field star that is 2 magnitudes dimmer.

Now head around a half degree northwest of Alpha (RA 20 19 29 Dec –70 51 36) for open cluster NGC 6800. Also known as Herschel VIII.21, this cluster is suitable for even smaller scopes but requires aperture to resolve completely. Discovered by Sir William in this month (10th) in 1784, you’ll like this ring-like arrangement of stars!

Now drop 2.7 degrees southwest of Alpha (RA 19 23 12 Dec +22 08 00) for yet another open cluster, NGC 6793. Discovered by Herschel in 1789 and logged as catalog object VIII.81, you’ll find a few more bright stars here. The challenge in this cluster is not so much being able to see it in a smaller telescope—but being able to discern a cluster from a star field! Try using the photo to help you distinguish it from the rest…

Sunday, September 6, 2009 – Today we celebrate many births. In 1891, it’s Yrjo Vaisala who produced telescope optics and discovered asteroids. In 1830, John Henry Dallmeyer, who was a master at making telescopes and eyepieces, was born. Last, in 1811, was James Melville Gilliss who founded the United States Naval Observatory.

Tonight we’ll return again to Vulpecula, but with a different goal in mind. What we’re after requires dark skies yet can be seen in either binoculars or a small telescope. Once you’ve found Alpha, begin about two finger-widths southeast, and right on the galactic equator you’ll find NGC 6823 (RA 19 43 10 Dec +23 17 54.). The first thing you will note is a fairly large, somewhat concentrated magnitude 7 open cluster.

Resolved in larger telescopes, the viewer may note these stars are the hot, blue-white variety. For good reason. NGC 6823 only formed about 2 billion years ago. Although it is some 6,000 light-years away and occupies around 50 light-years of space, it’s sharing the field with something more—a very large emission/reflection nebula, NGC 6820 (RA 19 42 27 Dec +23 05 14).

In the outer reaches of star cluster NGC 6823, new stars are being formed in masses of gas and dust as hot radiation is shed from the brightest of the stellar members of this pair. Fueled by emission, NGC 6820 isn’t always an easy visual object; it is faint and covers almost four times as much area as NGC 6823. But trace the edges very carefully, since the borders are much more illuminated than the central cluster region. Take the time to really observe this one! The processes going on here are very much like those in the ‘‘Trapezium’’ area of the Orion nebula. Be sure to mark your siting in your observing notes. NGC 6823 is Herschel VII.18 and NGC 6820 is also known as Marth 401!

Did you catch last week’s awesome Jupiter events? If not – then enjoy this great footage taken by the one and only Joe Brimacombe. (Not only is Dr. Joe cool… but he’s also one of the best observers I know!)

Perhaps you need another little nudge to get you out and observing, huh? Then here’s a list of Jupiter activities over the weekend:

Friday

00:58 UT, Io begins transit of Jupiter.
01:28 UT, Io’s shadow begins to cross Jupiter.
03:16 UT, Io ends transit of Jupiter.
03:48 UT, Io’s shadow leaves Jupiter’s disk.
22:10 UT, Io enters occultation behind Jupiter.

Saturday

01:00 UT, Io exits eclipse by Jupiter’s shadow.
02:36 UT, Europa exits eclipse by Jupiter’s shadow.
19:24 UT, Io begins transit of Jupiter.
19:58 UT, Io’s shadow begins to cross Jupiter.
21:42 UT, Io ends transit of Jupiter.

Sunday

16:36 UT, Io enters occultation behind Jupiter.
17:06 UT, Europa begins transit of Jupiter.
18:14 UT, Europa’s shadow begins to cross Jupiter.
18:20 UT, Ganymede enters occultation behind Jupiter.
19:28 UT, Io exits eclipse by Jupiter’s shadow.

Now get out there and observe!!

This week’s awesome images are (in order of appearance): Full Moon (credit—NASA), Omicron 1 Cygni, NGC 6800, NGC 6793, NGCs 6823 (central) and 6820 (credit—Palomar Observatory, courtesy of Caltech) and Jupiter footage courtesy of Joe Brimacombe. We thank you so much!

August 28, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast: August 28-30, 2009

Greetings, fellow SkyWatchers! Are you ready for a little lunacy this weekend? Yes, it’s back – but there is no other distant world whose features we can study quite so clearly and as well as the Earth’s companion – the Moon. If it’s been awhile since you turned a telescope or binoculars its way, why not spend an evening or two enjoying some of its features before it becomes overwhelmingly bright? There are other bright objects we often take for granted as well, too… Such as colorful and challenging double stars. If that’s not enough for you – then keep your eyes wide open – because some very cool things are about to happen with Jupiter’s moons! Time to dust off your optics and I’ll see you in the backyard…

Friday, August 28, 2009 – When we begin our observations tonight, we’ll start by having a look at another great binocular or telescope study crater, Archimedes. You’ll find it located in the Imbrium plain north of the Apennine Mountains and west of Autolycus.

Under this lighting, the bright ring of this Class V walled plain extends 83 kilometers in diameter. Even though it looks to be quite shallow, it still has impressive 2,150-meter-high walls. To its south is a feature not often recognized, the Montes Archimedes. Although this relatively short range is heavily eroded, it still shows across 140 km of lunar topography. Look for a shallow rima that extends southeast across Palus Putredinus toward the Apennines. Mark your challenge notes!

Keep those binoculars handy, as we look toward the Northern Cross, otherwise known as Cygnus the Swan. Start at the Swan’s beak—Albireo—and hold the binoculars very steady. Can you make out two stars where you thought there was one? If so, then you are seeing 3.2-magnitude Albireo’s distant companion. But don’t stop with binoculars; bring out the scope and have another look at Beta Cygni (RA 19 30 45 Dec +27 57 55). Albireo’s brighter star is a warm golden yellow and the fainter is a pristine aqua blue. Many astronomers agree this is the premier pair of colors in the heavens!

Saturday, August 29, 2009 – If you stayed out late, or decided to get up early, this morning is a scenic opportunity for binoculars. Just before dawn, look for Mars well risen along the ecliptic plane and aim your optics its way and see what you discover. That’s right! Messier 35 will be about a degree away…

As you start observing this evening, keep an eye on your time for 6:42 UT and watch Jupiter if you live in North America. Believe it or not, Io will partially occult Europa and the two will seem to meld together like a snowman for 13 minutes. And check back later! For at 7:38 UT, its shadow will take a very small bite out of it for approximately 8 minutes!

Our lunar mission for tonight is to move south, past the crater rings of Ptolemaeus, Alphonsus, Arzachel, and Purbach, until we end up at the spectacular crater Walter.

Named for Dutch astronomer Bernhard Walter, this 132- by 140-kilometer-wide lunar feature offers up amazing details at high power. It is worthwhile to take the time to study the differing levels, which drop to a maximum of 4,130 meters below the surface. Multiple interior strikes abound, but the most fascinating of all is the wall crater Nonius. Spanning 70 kilometers, Nonius would also appear to have a double strike of its own—one that’s 2,990 meters deep!

Although it will be tough to locate with the unaided eye thanks to the Moon near Lambda, let’s take a closer look at one of the most unsung stars in this region of sky—Eta Sagittarii (RA 18 17 37 Dec -36 45 42). This M-class giant star will display a wonderful color contrast in binoculars or scopes, showing up as slightly more orange than stars in the surrounding field. Located 149 light-years away, this irregular variable is a source of infrared radiation and is a little larger than our own Sun, yet is 585 times brighter. At around 3 billion years old, Eta has either expended its helium core or just began to fuse carbon and oxygen, creating an unstable star capable of changing its luminosity by about 4%. But have a closer look, for Eta is also a binary system with an 8th magnitude companion!

Sunday, August 30, 2009 – For observers in eastern North America, keep an eye on the time again tonight and watch Jupiter. At 5:44 UT, Io will graze Ganymede for 7 minutes and at 7:47 UT, its shadow will make a stately 22 minute pass, covering about 1/3 of the small moon in shadow!

Tonight let’s do a little Moon-shadowing of our own as we head to the western shore of Mare Cognitum and look along the terminator for the Montes Riphaeus—the ‘‘Mountains in the Middle of Nowhere.’’ But are they really mountains? Let’s take a look…

At its widest, this unusual range spans about 38 kilometers and runs for a distance of about 177 kilometers. Less impressive than most lunar mountain ranges, some peaks reach up to 1,250 meters high, making these summits about the same height as our Earthly volcanoes Mounts St. Augustine and Kilauea. While we are considering volcanic activity, consider that these peaks are the only things left of Mare Cognitum’s walls after the lava filled them in. At one time, this area may have included some of the tallest lunar features!

Tonight let’s have a look at the second brightest star of the Summer Triangle—Altair (RA 19 50 47 Dec +08 52 06). Like Vega, 16-light-year-distant Alpha Aquilae is a Sirius-type star, which is several times the size and mass of our Sun. Such stars burn hotter at the surface (approaching 10,000 Kelvin) and appear much whiter to the eye as a result. An unusual feature of Altair is its exceedingly high speed of rotation, requiring just 6 hours to complete an ‘‘Altairian day’’ at the equator. Because of this, its girth is significantly greater than its height, and gases on the equator move along at the surprising rate of 150 kilometers per second! As you observe Altair telescopically, look for a 10th magnitude companion roughly 3′ to the northwest.

Still more? Then while you’re out this weekend, have a go at the outer planets. While it takes several observations to be sure you’ve capture tiny Pluto by Gamma Cap, more northeastern Neptune is fairly easy and so is Uranus in Pisces. This rough finderchart will help you along the way – although most of these stars won’t be visible thanks to the bright influence of the Moon. So how do you find them? Use primary stars that do show – like Alpha Peg – to begin your search. For Uranus? Try about a handspan southeast, just as Neptune will be roughly two finger widths northeast of Gamma Cap.

This week’s awesome photos are (in order of appearance): Archimedes (credit—Wes Higgins), Beta Cygni (credit—Palomar Observatory, courtesy of Caltech), Albategnius to Walter (credit—Alan Chu), Eta Sagittarii (credit—Palomar Observatory, courtesy of Caltech), Montes Riphaeus (credit—Greg Konkel) and Alpha Aquilae: Altair (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

August 21, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – August 21-23, 2009

Greetings, fellow SkyWatchers! Are you ready for the weekend? Then let’s enjoy the nights ahead as we fly along the Milky Way on the wings of the Swan and hunt down some very different star clusters in the night with the Fox. Do you need a smile? Then you’ll find one with with a delightful asterism called the “Coat Hanger”! How about a Herschel challenge? We’ve got that, too. In the mood to just stargaze? Then stick around – because the Perseid Meteor Shower hasn’t ended just yet. (We’ve got something very special inside here to show you!) Time to get out your telescopes and binoculars and I’ll see you outside…

Friday, August 21, 2009 – On this date in 1993, the Mars Observer was lost. . . But you can’t miss Mars at its peak just before dawn!

Tonight it’s time for us to fly with the ‘‘Swan’’ as the graceful arch of the Milky Way turns overhead. We’ll start by taking a look at a bright star cluster that’s equally great in either binoculars or telescope, M39.

Located about a fist-width northeast of Deneb (Alpha Cygni), you will easily see a couple of dozen stars in a triangular pattern. M39 (RA 21 31 48 Dec +48 27 00) is particularly beautiful because it will seem almost three-dimensional against its backdrop of fainter stars. Younger than the Coma Berenices cluster, and older than the Pleiades, the estimated age of M39 is at least 230 million years. This loose, bright, galactic cluster is around 800 light-years away. Its members are all main sequence stars, and the brightest of them are beginning to evolve into giants.

For more of a challenge, try dropping about a degree south-southwest (RA 21 29 00 Dec +47 08 00) for NGC 7082, also known as H VII.52. Although it is a less rich, less bright, and far less studied open cluster, at magnitude 7.5 NGC 7082 is within range of binoculars and is on many open cluster observing lists. With only a handful of bright stars to NGC 7082’s credit, larger telescopes are needed to resolve out many of the fainter members. Be sure to mark your notes for both objects!

Saturday, August 22, 2009 – Born this date in 1833 was Samuel Pierpont Langley, who investigated the relationship between solar phenomena and meteorology. Is that why we always have clouds when solar activity is at its best?

Tonight we’ll hunt with the ‘‘Fox’’ as we head to Vulpecula to try two more open star cluster studies. The first can be done easily with large binoculars or a low power scope. It’s a rich beauty in the constellation of Vulpecula but is more easily found by moving around 3 degrees southeast of Beta Cygni (RA 19 35 48 Dec +25 13 00).

Known as Stock 1, this stellar swarm contains 50 or so members of varying magnitudes, which you will return to often. With a visual magnitude of near 5, loose associations of stars—like Stock clusters—are the subject of recent research. The latest information indicates that the members of this cluster are truly associated with one another.

A little more than a degree to the northeast is NGC 6815 (RA 19 40 44 Dec +26 45 32). Although NGC 6815 is a slightly more compressed open cluster, it has no real status among deep-sky objects, but it is another one to add to your collection of things to do and see!

Sunday, August 23, 2009 – On this date in 1609, Galileo demonstrated the telescope for the first time. Tonight we’ll aim our own optics at an asterism known as the ‘‘Coat Hanger,’’ which is also known as Brocchi’s Cluster, or Collinder 399. Let the colorful double star Beta Cygni—Albireo—be your guide as you move about 4 degrees to its south-southwest (RA 19 25 24 Dec +20 11 00). You will know this cluster when you see it, because it really does look like a coat hanger!

Enjoy its red stars! Discovered by Al Sufi in 964 AD, this 3.5 magnitude collection of stars was again recorded by Hodierna. Thanks to its extended size of more than 60′ it escaped the catalogs of both Messier and Herschel. Only around a half dozen stars share the same proper motion, which may make it a cluster much like the Pleiades, but studies suggest it is merely an asterism—but one with two binary stars at its heart.

And for larger scopes? Fade east to the last prominent star in the cluster (RA 19 30 36 Dec +20 16 00) and power up. NGC 6802 awaits you! At near magnitude 9, Herschel VI.14 is a well-compressed open cluster of faint members. The subject of ongoing research in stellar evolution, this 100,000-year old cluster is on many observing challenge lists!

Over the weekend, be sure to keep an eye out for stray Perseid meteors, because the show hasn’t ended yet! Although activity has slowed considerably, your chances are above average of catching a bright streak while you’re out enjoying the stars. It was a wonderful year for the Perseids and even if you were clouded out, we’ve still managed to catch the action for you…

Many thanks to John Chumack of Chumack Observatory (Dayton, Ohio) for all of his hard work in capturing and editing the footage from his All Sky Camera from the nights of August 11-14th. He’s trimmed the video to 5 frames per second and within this less than one minute clip, you’ll see over 200 meteors and the Moon rise three times! Were the Perseids a success? You bet. Just as John how he finished his film… “I ended it with the brightest…” said John, “A -8 magnitude fireball!”

Keep looking up! You’ll never know when it might be your lucky night…

This week’s awesome images are (in order of appearance): M39, NGC 7082, Stock 1, NGC 6815 (credit—Palomar Observatory, courtesy of Caltech), Collinder 399 (credit—Gil Estel), NGC 6802 (credit—Palomar Observatory, courtesy of Caltech) and Perseid Meteor Storm Video courtesy of John Chumack. We thank you so much!!

August 14, 2009December 24, 2015 by Tammy Plotner

Weekend SkyWatcher’s Forecast – August 14-16, 2009

Greetings, fellow SkyWatchers! Have you had a wonderful week chasing the Perseid Meteor shower? Well, the show isn’t over yet. Enjoy this weekend’s darker skies and keep watching! While you’re out, why not take a pair of binoculars with you and do a little cluster hunting? If you’re feeling energetic – take out the telescope and resolve them. Who knows what you might learn if you listen to what’s out there… Things like where to find chemically peculiar stars – or a runaway black hole! It’s all waiting for you in the night….

Friday, August 14, 2009 – If you were up well before dawn this morning watching the Perseids, did you notice the Pleiades brushing by the Moon? What a lovely sight! I wonder if it was an occultation event somewhere?

Tonight let’s venture about three finger-widths northeast of Lambda Sagittarii to visit a well known but little visited galactic cluster—M25 (RA 18 31 42 Dec -19 07 00). Discovered by Cheseaux and then cataloged by Messier, it was observed and recorded by William Herschel, Johann Elert Bode, Admiral Smythe, and T.W.Webb but never added to the NGC catalog of John Herschel! Thanks to J.L.E. Dreyer, it did make the second Index Catalog as IC 4725.

M25 is seen even with the slightest optical aid, and this 5th magnitude cluster contains two G-type giants as well as a Delta Cephei-type variable with the designation of U, which changes about 1 magnitude in a period of less than a week. It’s very old for an open cluster, perhaps near 90 million years, and the light you see tonight left the cluster over 2,000 years ago. Although binoculars will see about a double handful of bright stars overlying fainter members, telescopes will reveal more and more as aperture increases. At one time it was believed to have only about 30 members, but this was later revised to 86. But recent studies by Archinal and Hynes indicate it may have as many as 601 member stars!

Saturday, August 15, 2009 – On this date in 2006, Voyager 1, the most distant manmade object, reached 100 astronomical units (AUs) from the Sun—meaning 100 times more distant from the Sun than Earth—about 15,000 million kilometers (9,300 million miles). Voyager 1 continues traveling at a rate of about a million miles per day and could cross into interstellar space within 10 years. What fanastic sights do you think it is seeing?

Tonight we’ll head toward the riches of Scorpius to have a look at three pristine open clusters. Begin your starhop at the colorful southern Zeta pair and head north less than 1 degree for NGC 6231 (RA 16 54 08 Dec -41 49 36).

Wonderfully bright in binoculars and well resolved in the telescope, this tight-open cluster was discovered by Hodierna before 1654. De Cheseaux cataloged it as object 9, Lacaille as II.13, Dunlop as 499, Melotte as 153, and Collinder as 315. No matter what catalog number you choose to put in your notes, you’ll find the 3.2-million-year young cluster shining as the ‘‘Northern Jewelbox!’’ For high power fans, look for the brightest star in this group, called van den Bos 1833, a
splendid binary.

About another degree north is the loose open cluster Collinder 316, with its stars scattered widely across the sky. Caught on its eastern edge is another cluster known as Trumpler 24, a site where new variables might be found. This entire region is encased in a faint emission nebula called IC 4628, making this low-power journey through southern Scorpius a red-hot summer treat!

Sunday, August 16, 2009 – Before dawn, look for the close pair of Mars and the Moon celebrating the 1744 birth on this date of Pierre Mechain! We know Mechain as Charles Messier’s assistant, but Mechain was himself a fine astronomer and mathematical prodigy. He discovered 11 comets, and provided 26 entries to Messier’s catalog. If he were alive today, Pierre would be eager to join us tonight for our studies.

Begin about a degree and a half south of twin Nu Scorpii for NGC 6242 (RA 16 55 36 Dec -39 28 00).

Discovered by Lacaille and cataloged as I.4, this object is also known as Dunlop 520, Melotte 155, and Collinder 317. At roughly magnitude 6, this open cluster is within binocular range but truly needs a telescope to appreciate its fainter stars. Although NGC 6242 might seem like nothing more than a pretty little cluster with a bright double star, it contains an X-ray binary that is a ‘‘runaway’’ black hole, surmised to have formed near the galactic center and vaulted into an eccentric orbit when the progenitor star exploded. Its kinetic energy is much like that of a neutron star or a millisecond pulsar, and it was the first black hole confirmed to be in motion.

Now head a little more than a degree east-southeast for NGC 6268 (RA 17 02 40 Dec -39 44 18).

At a rough magnitude of 9, this small open cluster can be easily observed in smaller scopes and resolved in larger ones. NGC 6268 itself is somewhat lopsided, with more of its members clustered near its western border. Although it, too, might not seem particularly interesting, this young cluster is highly evolved and contains some magnetic, chemically peculiar stars; it has some Be-class, or metal weak, members as well.

Until next week? Keep on yelling when the Perseids fly over! I’m sure St. Lawrence would approve…

This week’s awesome images are (in order of appearance): M25 (credit—Palomar Observatory, courtesy of Caltech), Voyager 1 (credit—NASA), NGC 6231, NGC 6242 and NGC 6268 (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

August 11, 2009December 24, 2015 by Tammy Plotner

Perseid Radio Astronomy from the Fourth Plinth With Chris Lintott

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Within hours, the peak of the annual Perseid meteor shower will begin. If you’re worried you’ll be clouded out, then let’s take a look at a different way that you can observe the activity… without your eyes!

Did you know that you can “listen” to meteor showers? If you’re a ham radio operator, then you prize the ionized trails that meteors leave in our atmosphere to allow further signals to “bounce” to more distant receivers. However, you don’t really need complicated equipment to listen to a meteor shower – just an FM receiver and an external antenna. Even your car radio will work!

Place your radio setting on the lowest frequency that doesn’t receive a clear signal and simply listen to the static. When a meteor passes overhead you’ll hear snatches of radio signals from distant stations, pops, buzzes, pings, shrieks, howls, and simple changes in the white noise. Sometimes it’s subtle – and sometimes it’s striking. One thing is for sure, the noises you hear are definitely out of this world! Your equipment can run the gambit from connecting a genuine outdoor FM antenna to an indoor receiver and recording with a tape deck for later playback, to a portable radio. I’ve even used an old television set connected to an outdoor television antenna tuned to channel 3. It’s all fun – and the results are amazing. Here are the dates for the 2009 Perseids.

To open the public’s eyes to just how easy radio meteor listening can be, astrophysicist Chris Lintott will be doing a presentation live in Trafalgar Square on August 14th, 19-20h BST. Chris is a co-presenter of the BBC’s “The Sky at Night” astronomy programme, and is a lecturer at University College London and the project he’s about to take part in is very unique… The Fourth Plinth.

This summer, sculptor Antony Gormley has invited the world to help create an astonishing living monument. He is asking the people of the UK to occupy the empty Fourth Plinth in Trafalgar Square in London, a space normally reserved for statues of Kings and Generals. They will become an image of themselves, and a representation of the whole of humanity. Every hour, 24 hours a day, for 100 days without a break, a different person will make the Plinth their own.

Because of the appalling levels of light pollution in London, Lintott remembered a radio-meteor demonstration given by Andy Smith of G7IZU Radio Reflection Detection and his friend David Entwistle for “The Sky at Night” a couple of years ago, and wanted to do something along those lines. Since no power or wiring are allowed on the Plinth, Chris will be utilizing a recording done by Andy beginning tonight… a talent he’s quite good at! For every hour from midnight on, G7IZU Radio Reflection Detection will be recording the Perseid event and sending Chris the most active hours as MP3 files. He’ll then play these
to the masses over an amplified speaker while holding up photos of how it all works.

If you’re interested in the live radio-meteor/astronomy demonstration, you can access a live video of the Fourth Plinth – and be sure to join them on August 14th, 19-20h BST for Chris Lintott’s presentation!

August 10, 2009December 24, 2015 by Tammy Plotner

2009 Perseid Meteor Shower – Double Peaks This Year!

2009 Perseid Meteor Shower Preview by John Chumack

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Are you ready for this year’s Perseid Meteor Shower? What will be the best place to watch and when will be the best date to see the most “shooting stars”? Follow along and let’s find out…

The Perseid meteor shower has a wonderful and somewhat grisly history. Often referred to as the “Tears of St. Lawrence” this annual shower coincidentally occurs roughly about the same date as the saint’s death is commemorated on August 10. While scientifically we know the appearance of the shooting stars are the by-products of comet Swift-Tuttle, our somewhat more superstitious ancestors viewed them as the tears of a martyred man who was burned for his beliefs. Who couldn’t appreciate a fellow who had the candor to quip “I am already roasted on one side and, if thou wouldst have me well-cooked, it is time to turn me on the other.” while being burned alive? If nothing else but save for that very quote, I’ll tip a wave to St. Lawrence at the sight of a Perseid!

While the fall rate – the number of meteors seen per hour – of the Perseids has declined in recent years since Swift-Tuttle’s 1992 return, the time to begin your Perseid watch is now. The random rate has already increased sharply and there is no guaranteed that skies will be clear on the predicted peak time – traditionally August 12 at approximately 11:00 GMT. The tears of St. Lawrence are already beginning to fall! Let’s join John Chumack via his Northeast Sky Camera #2 in his backyard Observatory in Dayton, Ohio, USA, for a look. This 5 hour movie was compressed to 10 seconds for web viewing.

Says John, “The brightest one occurred when the radiant was low on the horizon around 1:27 a.m. This fireball was at around -8 magnitude or greater, even with all the strong moonlight, some of the meteors are very bright! This one had a double explosion too!”

Astronomers are now estimating a double peak this year for viewers in the eastern portion of North America on Wednesday morning the 12th of August 2009. One peak should occur around 1:00 a.m. EST and the other peak around 5:30 a.m. EST. However, let’s assume that not all of us can be in that place and be up at that time… So let’s take a more practical look at observing the Perseid Meteor Shower.

Perseid meteor activity begins about midnight no matter where you live, but they can happen earlier, too. Because we are also contending with a Moon which will interfere with fainter meteors, the earlier you can observe, the better. There is no harm in beginning Tuesday night before the Moon rises. The general direction to face will be east around midnight and the activity will move overhead as the night continues. While waiting for midnight or later for activity to pick up to begin isn’t a pleasant prospect, by then we are looking more nearly face-on into the direction of the Earth’s motion as it orbits the Sun, and the radiant – the constellation of the meteor shower origin – is showing well. However, it won’t be long until the Moon also begins to show very well, indeed! Put an obstruction such as the edge of a house or a tree between you and Selene… Even if you just open an umbrella, the very act of shielding some of the light will most certainly help you to see far more meteors than if you don’t. For those of you who prefer not to stay up late? Try getting up early instead!

How many can you expect to see? A very average and cautiously stated fall rate for this year’s Perseids would be about 30 per hour, but remember – this is a collective estimate. It doesn’t mean that you’ll see one every two minutes, but rather you may see four or five in quick succession with a long period of inactivity in between. You can make your observing sessions far more pleasant by planning for inactive times in advance. Bring a radio along, a thermos of your favorite beverage, and a comfortable place to observe from. The further you can get away from city lights, the better your chances will be. If you’re cloud out on the peak date, don’t stop watching – because activity continues on for several days!

Will this 2000 year-old meteor shower be a sparkling success or a total dud? You’ll never know unless you go out and try yourself. One thing we do know is the Perseids are one of the most predictable of all meteor showers and even an hour or so of watching should bring a happy reward! Wishing you clear skies and good luck…