Author: Tammy Plotner

Greetings, fellow SkyWatchers! Have you been watching Jupiter and the Moon make a pass at each other in the early morning sky? What an incredible sight. With the slightly later rise of Selene during the weekend hours, we can take advantage of the earlier evening to do some deep sky studies. However, if you’re just in the mood to kick back in a lawn chair and do a little stargazing, you’ll probably spot some early Perseid meteors gracing the night. I’ll give you a full report on the watching the Perseid Meteor shower just a little bit closer to the date so you won’t forget! For now… Why not join me in the back yard? We’ve got a little history, a little mystery and a telescope waiting for you…

Friday, August 7, 2009 – Today marks the 1726 birth of James Bowdoin, astronomer and friend of Benjamin Franklin. Although Bowdoin suffered many years from consumption, which was finally the cause of his death, he was always vigorous in public affairs. He was one of the founders, and first president, of the American academy of arts and sciences, and left it his valuable library. He also aided in founding the Massachusetts humane society, and in 1779 was made a fellow of Harvard College. He was given the degree of LL.D. by the University of Edinburgh, and was a fellow of the royal societies of London and Edinburgh. Several of his papers appear in the memoirs of the society, among which is one whose object is to prove that the sky is a real concave body enclosing our system, and that the Milky Way is an opening in this, through which the light of other systems reaches us.

What do you think he would have thought if he could be with us tonight as we return to our studies with the globular M14, one of the clusters nearer to the galactic center? Located about 16 degrees (less than a handspan) south of Alpha Ophiuchi (RA 17 37 36 Dec +03 14 45), this 9th magnitude, Class VIII cluster can be spotted with larger binoculars, but only fully appreciated with the telescope.

When studied spectroscopically, globular clusters are found to be much lower in heavy element abundance than stars such as own Sun. These earlier generation stars (Population II) began their formation during the birth of our galaxy, making globular clusters the oldest formations we can study. In comparison, the disk stars have evolved many times, going through cycles of starbirth and supernova, which in turn enriched the heavy element concentration in star-forming clouds. Of course, as you may have guessed, M14 breaks the rules. M14 contains an unusually high number of variable stars—in excess of 70—with many of them known to be the W Virginis type. In 1938, a nova appeared in M14, but it was undiscovered until 1964, when Amelia Wehlau of the University of Ontario was surveying the photographic plates taken by Helen Sawyer Hogg. The nova was revealed on eight of these plates taken on consecutive nights and showed itself as a 16th magnitude star—andwas believed to be at one time almost five times brighter than the cluster members. Unlike 80 years earlier with T Scorpii in M80, actual photographic evidence of the event existed. In 1991, the eyes of the Hubble were turned its way, but neither the suspect star nor traces of a nebulous remnant were discovered. Then, 6 years later, a carbon star was discovered in M14. To a small telescope, M14 will offer little to no resolution and will appear almost like an elliptical galaxy, lacking in any central condensation. Larger scopes will show hints of resolution, with a gradual fading toward the cluster’s slightly oblate edges. A true beauty!

Saturday, August 8, 2009 – On this date in 2001, the Genesis Solar Particle Sample Return mission was launched on its way toward the Sun. On September 8, 2004, it returned with its sample of solar wind particles. Unfortunately, a parachute failed to deploy, causing the sample capsule to plunge unchecked into the Utah soil. Although some of the specimens were contaminated, many did survive the mishap. So what is ‘‘star stuff?’’ Mostly highly charged particles generated from a star’s upper atmosphere flowing out in a state of matter known as plasma.

Before moonrise, let’s study one of the grandest of all solar winds as we seek out an area about three finger-widths above the Sagittarius teapot’s spout as we have a look at the magnificent M8 (RA 18 03 37 Dec +24 23 12). Visible to the unaided eye as a hazy spot in the Milky Way, fantastic in binoculars, and an area truly worth study in any size scope, this 5,200-light-year-diameter area of emission, reflection, and dark nebulae has a rich history. Its involved star cluster—NGC 6530—was discovered by Flamsteed around 1680 and the nebula by Le Gentil in 1747. Cataloged by Lacaille as III.14 about 12 years before Messier listed it as number 8, its brightest region was recorded by John Herschel, and dark nebulae were discovered within it by Barnard.

Tremendous areas of starbirth are found in this region, while young, hot stars excite the gas in a region known as the ‘‘Hourglass’’ around the stars Herschel 36 and 9 Sagittarii. Look closely around cluster NGC 6530 for Barnard Dark Nebulae B 89 and B 296 at the nebula’s southern edge. . .and try again on a darker night. No matter how long you choose to swim in the ‘‘Lagoon,’’ you will surely find more and more things to delight both the mind and the eye!

Sunday, August 9, 2009 – On this date in 1976, the Luna 24 mission was launched on a return mission of its own, not to retrieve solar winds’ samples but lunar soil! Remember this mission as we take a look at its landing site in the weeks ahead. Tonight we’ll return to the nebula hunt as we head about a finger-width north and just slightly west of M8 for the ‘‘Trifid’’ (RA 18 02 23 Dec +23 01 48).

M20 was discovered by Messier on June 5, 1764, and much to his credit, he described it as a cluster of stars encased in nebulosity. This is truly a wonderful observation, since the Trifid could not have been easy to spot, given his equipment. Some 20 years later William Herschel (although he usually avoided repeating Messier objects) found M20 of enough interest to assign separate designations to parts of this nebula—IV.41, V.10, V.11, V.12.

The word ‘‘Trifid’’ was used to describe its beauty by John Herschel. Although M20 is a very tough call in binoculars, it is not impossible with good conditions to see the light of an area that left its home nearly a millennium ago. Even smaller scopes will pick up this faint, round, hazy patch of both emission and reflection, but you will need aversion to see the dark nebula that divides it. This was cataloged by Barnard as B 85. Larger telescopes will find the Trifid as one of the very few objects that actually appears much in the eyepiece as it does in photographs—with each lobe containing beautiful details, rifts, and folds best seen at lower powers. Look for its cruciform star cluster and its fueling multiple system while you enjoy this triple treat tonight!

For now, keep an eye on the sky for the coming of the annual Perseid Meteor Shower! You’ll see a great increase in activity beginning now – despite the moonlight. The peak will be mid-week, but I’ll be back with an update on who, when, where, why and how very soon… Until then? Wishing you clear skies!

This week’s awesome images are (in order of appearance): James Bowdoin (historical image), (credit—NOAO/AURA/NSF), Genesis Spacecraft (credit—NASA), M8: the Lagoon Nebula (credit—NOAO/AURA/NSF), Luna 24 launch (press release photo) and M20: the Trifid nebula (credit—Palomar Observatory, courtesy of Caltech). We thank you so much!

Heads up for our friends in Southeast Europe, Northeast Africa, South America! In a matter of hours Antares is going to be occulted by the Moon! See the IOTA pages for times and locations and get out and watch! This weekend is a great time to do some lunar explorations and catch up on some double star work, too. Have you been watching for the impact site on Jupiter? Even if you don’t have a telescope, I’ve got another video in here to share with you that’s gonna’ blow your mind. Are you ready to do some observing? Then I’ll see you in the back yard…

Friday, July 31, 2009 – Heads up for our friends in Southeast Europe, Northeast Africa, South America! You don’t have long until Antares is going to be occulted by the Moon! See the IOTA pages for times and locations and get out and watch! For many of us the bright red “Rival of Mars” will simply be a close and appealing visitor tonight, so take this opportunity to view an occultation for yourself thanks to a little video magic from Joe Brimacombe!

Now let’s take an entirely different view of the Moon as we do some ‘‘mountain climbing.’’ Tonight the most outstanding feature on the Moon will be the emerging Copernicus, but since we’ve delved into the deepest areas of the lunar surface, why not climb to some of its peaks?

Using Copernicus as our guide, to the north and northwest of this ancient crater lies the Carpathian Mountains, ringing the southern edge of Mare Imbrium. As you can see, they begin well east of the terminator, but look into the shadow! Extending some 40 kilometers beyond the line of daylight, you will continue to see bright peaks, some of which reach over 2,000 meters in height! When the area is fully revealed tomorrow, you will see the Carpathian Mountains eventually disappearing into the lava flow that once formed them. Continuing onward to Plato, which sits on the northern shore of Imbrium, we will look for the singular peak of Pico. It is between Plato and Mons Pico that you will find the scattered peaks of the Teneriffe Mountains. These may be the remnants of much taller summits of a once stronger range, but only about 1,890 meters still survives above the surface. Time to power up! To the west of the Teneriffes, and very near the terminator, you will see a narrow series of hills cutting through the region west-southwest of Plato. This is known as the Straight Range—Montes Recti—and some of its peaks reach up to 2,072 meters. Although this doesn’t sound particularly impressive, that’s over twice as tall as the Vosages Mountains in Central Europe, and on the average very comparable to the Appalachian Mountains in the eastern United States.

Saturday, August 1, 2009 – Let’s continue our lunar mountain climbing expedition and look at the ‘‘big picture’’ on the Moon’s surface. Tonight all of Mare Imbrium is bathed in sunlight, and we can truly see its shape. Let’s identify the mountain ranges again. Starting at Plato and moving east to south to west you will find the Alps, the Caucasus, and the Apennines (where Apollo 15 landed at the western end of Palus Putredinus), respectively. Next come the Carpathian Mountains just north of Copernicus.

Look at their form closely. Doesn’t it appear that once upon a time an enormous impact created the entire area? The Imbrium impact. . . Compare it to the younger Sinus Iridium. Ringed by the Juras Mountains, it may have also been formed by a much later and very similar impact.

And you thought they were just mountains. . .

Tonight let’s honor the 1891 birth on this date of Helen Sawyer Hogg, who cataloged distances to variable stars in globular clusters. Although it’s too bright to globular hunt tonight, we can start with our eyes on Delta Ophiuchi (RA 16 14 20 Dec +03 41 39), another undiscovered gem. Known as Yed Prior (the ‘‘Hand’’), look for its optical double Epsilon to the southeast, handily named Yed Posterior. Now have a look at this area in binoculars or a telescope, using absolutely minimum power. Delta Ophiuchi is 170 light-years from us, while Epsilon is 108. But look at the magnificent field they share. Stars of every spectral type are together in an area of sky that could easily be covered by a small coin held at arm’s length. Enjoy this fantastic field, from the hot blue youngsters to the old red giants!

Sunday, August 2, 2009 – Today we celebrate the official adoption of Greenwich Mean Time (GMT) in 1880. Tonight take time to head north of Sinus Iridum, across Mare Frigoris and northeast of the punctuation of Harpalus, and revisit the grand crater J. Herschel.

Although it looks small because it is seen on the curve, this wonderful old walled plain named for John Herschel contains some very tiny details. Its southeastern rim forms the edge of Mare Frigoris, and the small (24 kilometers) crater Horrebow dots its southwestern edge. The crater walls are so eroded with time that not much remains of the original structure. Look for many very small impact craters dotting J. Herschel’s uneven basin and exterior edges. Why return to a previous study? If you can spot the small central crater C, you are resolving a feature only 12 kilometers wide from some 385,000 kilometers away!

While we’re out, let’s have a look at another astounding system called 36 Ophiuchi, located about a thumb-width southeast of Theta (RA 17 15 20 Dec +26 36 10). Situated in space less than 20 light-years from Earth, even small telescopes can split this pair of 5th magnitude K-type giants—stars very similar to our own Sun. Larger telescopes can pick up the C component as well. Be sure to mark your lists with both of your observations tonight, because J. Herschel is a Lunar Club Challenge, and 36 Ophiuchi is on many doubles’ challenge lists.

If you haven’t taken the “time” to hunt down the impact site on Jupiter, then you’d better! Even if it isn’t visible while you’re out observing, you can always enjoy all the great features Jupiter has to offer. Who knows? You might catch a shadow transit… Or just enjoy the waltz of the Galiean moons as they shuttle around the scarred giant. Remember to use as much magnification as possible when looking for the impact site! While videos like Joe Brimacombe’s (seen here) make it very clear, viewing through a small telescope isn’t quite that crisp and easy. The details become much more pronounced in photographs than what can be seen visually, so extra magnification doesn’t harm… It actually helps to dim Jupiter and will pick up the contrast for you. But, take a look at what a Takahashi Mewlon can do!

Absolutely Tak sharp… For now? Wishing you clear and steady skies!

This week’s awesome images are (in order of appearance): Februrary 18, 2009 Antares Occultation Movie (credit – Joe Brimacombe), Montes Teneriffe and Montes Recti (credit—Wes Higgins), Gibbous Moon (credit—Greg Konkel), Delta Ophiuchi (credit—Palomar Observatory, courtesy of Caltech), Crater J. Herschel (credit—Alan Chu), 36 Ophiuchi (credit—Palomar Observatory, courtesy of Caltech) and Jupiter Impact Movie by Joe Brimacombe. We thank you so much!!

Greetings, fellow SkyWatchers! Has everyone enjoyed the Apollo revival? I certainly have – and now the Moon is gently returning to evening sky and offering us great opportunities over the coming evenings to do a little bit of study with binoculars and telescopes. Look for its slender crescent just after sunset! This weekend we’re going to try an open cluster you may never have seen that works well for small optics and a Herschel object with a real twist. Need more? Then we’ll check out a beautifully colored double star, too… But not the one you expect! Grab your telescopes and binoculars and I’ll see you in the back yard…

Friday, July 24, 2009 – Today let’s start with the 1853 birth on this date of Henri-Alexandre Deslandres. Do you recognize his name from our lunar studies? He invented the spectroheliograph to photograph the Sun in monochromatic light! Deslandres also observed the spectra of planets and stars and measured their radial velocities. Did you see the very young crescent of the Moon during twilight? The Moon played an important role in history on this date. The Apollo 11 astronauts splashed down from their return from the Moon on this date in 1969! Only 15 years before, in 1954, the sound of a human voice had been reflected off the Moon’s surface and returned to Earth. James H. Trexler at the Naval Research Laboratory spoke into a microphone at the laboratory’s Maryland facility, and the sound was relayed back 2.5 seconds later. Although ‘‘Operation Moon Bounce’’ was only a repetition of vowel sounds, Trexler felt the project held promise as a communications and radar intercept device. It might be worth it to point out that many radars are very close to the theoretical possibility of contacting the Moon, and hence the practicality of building a system capable of intercepting these systems by reflections from the Moon is not beyond the realm of possibility.

Tonight we start with a group of young stars beginning their stellar evolution and end with an old solitary elder preparing to move onto an even ‘‘higher realm.’’ Open cluster IC 4665 is easily detected with just about any optical aid about a finger-width north-northeast of Beta Ophiuchi (RA 17 46 18 Dec +05 43 00). Discovered by Philippe Loys de Cheseaux in the mid-1700s, this 1,400 light year distant cluster consists of about 30 mixed-magnitude stars all less than 40 million years of age. Despite its early discovery, IC 4665 did not achieve broad enough recognition for Dreyer to include it in the late nineteenth-century New General Catalog (NGC), and it was later added as a supplement to the NGC in the Index Catalog of 1908. Be sure to use low power to see all of this large group.

Saturday, July 25, 2009 – Today we celebrate a success of the U.S.S.R. space program with the achievement of cosmonaut Svetlana Savitskaya, the first woman to walk in space (in 1982 on this date) and only the second female to go into space, preceding Sally Ride. Today is also the date of the 1973 launch of Soviet Mars 5 probe. Although it didn’t complete its full mission, it did send back 60 photos of the Martian Southern Hemisphere!

Although poor position makes study difficult during the first few lunar days, be sure to look for the ancient impact Vendelinus. Spanning 150 kilometers in diameter and with walls reaching up to 4,400 meters in height, lava flow has long ago eradicated any interior features. Its old walls hold mute testimony to later impact events such as crater Holden on the south shore, larger Lame on the northeast edge, and sharp Lohse northwest. Mark your challenge list!

Tonight’s challenge is Herschel I.44, also known as NGC 6104, a 9.5-magnitude globular cluster around two finger-widths northeast of Theta Ophiuchi and a little more than a degree due east of star 51 (RA 17 38 37 Dec –23 54 31). Discovered by William Herschel in 1784 and often classed as ‘‘uncertain,’’ this halo object has been pegged by today’s powerful as a Class VIII and given a rough distance from the galactic center of 8,800 light-years. Although neither William nor John could resolve this globular and listed it originally as a bright nebula, studies in 1977 revealed a nearby suspected planetary nebula named Peterson 1. Thirteen years later, further study revealed this wasn’t a nebula at all but evidence of a symbiotic star. Symbiotic stars are a true rarity—not a single star at all but a binary system. A red giant dumps mass toward a white dwarf in the form of an accretion disk. When this reaches critical mass, it then causes a thermonuclear explosion, resulting in a planetary nebula. Although no evidence exists that this object is located within metal-rich NGC 6401, just being able to see it in the same field makes this journey both unique and exciting!

Sunday, July 26, 2009 – On this date in 1969 in a vacuum-sealed room, the very first sample return of Moon rocks was studied.

Our own vacuum of space awaits as we view the area around Mare Crisium to have a look at this month’s lunar challenge—Macrobius.

You’ll find it just northwest of the Crisium shore. Spanning 64 kilometers in diameter, this Class I impact crater drops to a depth of nearly 3,600 meters—about the same as many of our Earthly mines. Its central peak rises to 1,100 meters and may be visible as a small speck inside the crater’s interior. Be sure to mark your lunar challenge lists, and look for other features you may have missed before!

Since the moonlight will now begin to interfere with our globular cluster studies, let’s waive these for a while as we take a look at some of the region’s most beautiful stars. Tonight your goal is to locate Omicron Ophiuchi, about a finger-width northeast of Theta (RA 17 18 00 Dec –24 17 02). At a distance of 360 light-years, the Omicron system is easily split by even small telescopes. The primary star is slightly dimmer than magnitude 5 and appears yellow to the eye. The secondary is near 7th magnitude and tends to be more orange in color. This wonderful star is on many doubles’ observing lists, so be sure to note it!

Are you wanting to keep an eye out for those dark markings of the Jupiter impact, too? Well, they’re there! Just remember if you’re new to astronomy that features on Jupiter rotate as the planet turns and we’re turning, too. Seeing the new “spots” requires some calculations and these areas will rotate into meridian view about 2 hours and 6 minutes after the Great Red Spot makes an appearance. Also remember that our own atmospheric seeing conditions play a great role as well! If it just so happens the dark spots will be making their appearance will Jupiter is still very low on the horizon, chances are your luck with seeing them in a small telescope won’t be high. But, don’t let that discourage you from looking! It doesn’t take long for a planet to rise to good observing height and the spots will stay visible for several hours as they rotate in and out on either side of your computed appearance time. (And don’t forget galiean moon shadow transits can also cause dark markings… but these will be very round!)

Until next week? Enjoy your observations and keep reaching for the stars!

This week’s awesome images are (in order of appearance): Henri Deslandres (historical image), IC 4665 (credit—Palomar Observatory, courtesy of Caltech), Vendelinus (credit—Alan Chu), NGC 6401 (credit—Palomar Observatory, courtesy of Caltech), Macrobius on the edge of Crisium (credit—Greg Konkel) Omicron Ophiuchi (credit—Palomar Observatory, courtesy of Caltech) and Jupiter (credit-Sky & Telescope: Sean Walker). We thank you so much!