Category: Observing

Greetings, fellow SkyWatchers! It’s Friiiiiiday… And time to head out to the Moon to begin some lunar exploration. Why not? This weekend commemorates Robert Goddard’s birthday! While we’re rocketing skyward, we’ll take a look at a great globular cluster that’s easy in both binoculars and telescopes, plus a few great stars you might or might not know about. For lucky viewers in South Africa and Australia? Head’s up for an Antares occultation! Are you ready? Then let’s head out into the night….

Friday, October 3, 2008 – Tonight we’ll begin on the lunar surface and go out on a limb – the southeastern limb – to have a look at an unusual crater. Named for the French agrochemist and botanist Jean-Baptiste Boussingault, this elliptical-appearing crater actually spans a handsome 71 kilometers. What makes Boussingault so unusual is that it is home to its own large interior crater – A. This double-ring formation gives it a unique stepped, concentric look that’s worth your time!

Now wait for the Moon to wester a bit and we’ll return to Pegasus and the incredible M15. Although skies are a bit bright, you can still have a very satisfactory look at M15 through any size binoculars or telescope.

You can find it easily just about two fingerwidths northwest of red Epsilon Pegasi – Enif (RA 21 29 58 Dec +12 10 00). Shining brightly at magnitude 6.4, low power users will find it a delightfully tight ball of stars, but scope users will find it unique. As resolution begins, sharp-eyed observers will note the presence of a planetary nebula – Pease 1. This famous X-ray source you have just seen with your eyes may have supernova remnants buried deep inside…

When we’re done? Let’s go have a look at Gamma Aquilae just for the heck of it. Just northwest of bright Altair, Gamma (RA 19 46 15 Dec +10 36 47) has the very cool name of Tarazed and is believed to be over 300 light-years away. This K3-type giant will show just a slight yellow coloration – but what really makes this one special is the low power field! Enjoy it in binoculars or drop in your favorite panoramic eyepiece and just relax… Sometimes there is peace and contentment in the light.

Saturday, October 4, 2008 – Today in 1957, the USSR’s Sputnik 1 made space history as it became the first manmade object to orbit the earth. The Earth’s first artificial satellite was tiny, roughly the size of a basketball, and weighed no more than the average man. Every 98 minutes it swung around Earth in its elliptical orbit…and changed everything. It was the beginning of the “Space Race.” Many of us old enough to remember Sputnik’s grand passes will also recall just how inspiring it was. Take the time with your children or grandchildren to check www.heavens-above.com for visible passes of the ISS, and think about how much our world has changed in just over half a century!

Do you remember the Professor Burg who discovered Antares’ companion during an occultation? Well, tonight we’re going to become a whole lot more familiar with the good professor, because it’s about to happen again! For almost all observers, at some time brilliant red Antares will be less than half a degree to the north of tonight’s crescent Moon. For South African and Australia, this will be a spectacular occultation, so be sure to check IOTA for precise times and locations on this universal date.

While we’re waiting on the event, let’s have a look at the crater named for Burg as we begin by using past study crater Posidonius as our guide. How many more of these craters can you identify?

If you walk along the terminator to the northwest, you’ll see the punctuation of 40 kilometer wide Burg just emerging from the shadows. While it doesn’t appear to be a grand crater like Posidonius, it has a redeeming feature: it’s deep – really deep. If Burg were filled with water here on Earth, it would require a deep submergence vehicle like ALVIN to reach its 3680 meter floor! This class II crater stands nearly alone on an expanse of lunarscape known as Lacus Mortis. If the terminator has advanced enough at your time of viewing, you may be able to see this walled-plain’s western boundary peeking out of the shadows.

Sunday, October 5, 2008 – Today marks the birthdate of Robert Goddard. Born in 1882, Goddard is known as the father of modern rocketry – and with good reason. In 1907, Goddard came into the public eye when a cloud of smoke erupted from the basement of the physics building in Worcester Polytechnic Institute, from which he had just fired a powder rocket. By 1914, he had patented the use of liquid rocket fuel, and the design of two- or three-stage solid fuel rockets. His work continued as he sought methods of lofting equipment ever higher, and by 1920 he had envisioned his rockets reaching the Moon. Among his many achievements, he proved that a rocket would work in a vacuum. By 1926 the first scientific equipment went along for the ride; by 1932, Goddard was guiding those flights; and by 1937 his motors were pivoting on gimbals and being controlled gyroscopically. His lifetime of work went pretty much unnoticed until the dawn of the Space Age, but in 1959 (14 years after his death) he received acclaim at last as NASA’s Goddard Space Flight Center was established in his memory.

Tonight let’s rocket to the Moon to explore a binocular curiosity located on the northeast shore of Mare Serenitatis. Look for the bright ring of Posidonius, which contains several equally bright points both around and within it. Now look at Mare Crisium and get a feel for its size. A little more than one Crisium’s length west of Posidonius you’ll meet Aristotle and Eudoxus. Drop a similar length south and you will be at the tiny, bright crater Linne on the expanse of Mare Serenitatis. So what’s so cool about this little white dot? With only binoculars you are resolving a crater that is one mile wide, in a seven mile wide patch of bright ejecta – from close to 400,000 kilometers away!

Tonight in 1923, Edwin Hubble was also busy as he discovered the first Cepheid variable in the Andromeda Galaxy. Hubble’s discovery was crucial in proving that the objects once classed as “spiral nebulae” were actually independent and external stellar systems like our own Milky Way.

While we’re out, let’s have a look at a Mira type variable, as we look about halfway between Beta and Gamma Cygni for Chi (RA 19 50 33 Dec +32 54 51).

Noted for being the second long-term variable discovered (by Gottfried Kirch in 1868), Chi is visible to the unaided eye when at maximum – but demands a telescope at minimum. Fluxing between magnitude 4 and 12, you’ll know if you’ve caught it at its lowest point when you can’t distinguish it from background stars! Of course, this is another wonderful cosmic joke on Bayer – for it was several years until the star he classed as visual returned to view. Maximum or minimum? Enjoy your own perceptions of this lovely red star!

Now, as the days pass… Watch as Jupiter and the Moon draw closer and then part company! It’s a lovely sight that doesn’t require any special equipment and makes for a relaxing evening of stargazing. Until next time, I wish you clear skies and a great weekend!

This week’s awesome images are: Crater Boussingault – Credit: Jim Mosher (LPOD), M15 – Credit: NOAO/AURA/NSF, Gamma Aquilae – Credit: Palomar Observatory, courtesy of Caltech, Sputnik 1 – Credit: NASA, 2005 Antares Occultation – Credit: John Chumack, Detail view of Posidonius – Credit: Greg Konkel, Robert Goddard – Credit: NASA, Crater Linne – Credit: Greg Konkel Annotations: Tammy Plotner and Chi Cygni at minimum (center of field) – Credit: Palomar Observatory, courtesy of Caltech. Many, many thanks! Each time we see these images it improves our understanding of what we look at and what we are looking for and their use is greatly appreciated!!

Greetings, fellow SkyWatchers! It’s a dark sky weekend and a great opportunity to really get to know some unusual deep sky objects – like brilliant open clusters and tiny compact galaxy groups. Even if you just sit outside and stargaze, you might catch a member of the Alpha Aurigid meteor shower! Are you ready? Then get out your binoculars and telescopes and let’s head out for adventure…

Friday, September 26, 2008 – Tonight we’ll begin our adventures with Vulpecula – it’s time to go fox hunting. What we’re after requires dark skies – but can be seen in both binoculars and a small telescope. Once you’ve found Alpha begin about two fingerwidths southeast and right on the galactic equator for 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 two million years ago.

Although it is some 6000 light-years away and occupies about 50 light-years of space, it’s sharing the field with something more – a very faint and very large emission/reflection nebula called NGC 6820.

In the outer reaches of the star cluster, 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’s faint and covers almost four times as much area as the cluster and using a filter helps. But, trace the edges very carefully, since the borders are much more illuminated than the region of the central cluster. It’s like a whisper against your eyes. Take the time to really observe this one! The processes going on are very much like those occurring in the Trapezium area of the Orion nebula.

Be sure to mark your observing notes. NGC 6823 is Herschel VII.18; and NGC 6820 is also known as Marth 401!

Saturday, September 27, 2008 – Today we celebrate the 1814 birth 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 – “Kirkwood Gaps.” Not only did he study the orbits of asteroids, but he was 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 it’s time to break out the muscle and challenge big telescope users to hone their skills. It’s galaxy hunting time and our destination for tonight is Hickson Compact Group 87 (RA 20 48 11 Dec -19 50 24)…

Several billion years ago, on the ecliptic plane about four degrees west-southwest of Theta Capricorni, and around 400 million light-years from our solar system, a galactic association decided to form their own “Local Group.” Orbiting around a common center about every 100 million years, their mutual gravity is pulling each of them apart – creating starbursts and feeding their active galactic nuclei. Small wonder they’re shredding each other… They’re only 170,000 light-years apart! One day they may even form a single elliptical galaxy bright enough for the average telescope to see – because as they are now, this group isn’t going to be seen with anything less than 20″ in aperture.

So, shall we try something a little more within the realm of reality? Then go ahead and drop about eight degrees south of Theta and try picking up on the NGC 7016/17/18 group (RA 21 07 20 Dec -25 29 15). Are they faint? Of course! It wouldn’t be a challenge if they were easy, would it? With an average magnitude of 14, this tight trio known as Leavenworth 1 is around 600 million light-years away. They’re very small, and not very easy to locate… But for those who like something a bit different?

I dare you…

Sunday, September 28, 2008 – As your starry mission this evening, we’ll continue our studies in Vulpecula with a spectacular open cluster – NGC 6940 (RA 20 34 24 Dec +28 17 00). At close to magnitude 6, you’ll find this unsung symphony of stars around three fingerwidths southwest of Epsilon Cygni.

Discovered by Sir William Herschel in 1784 and logged as H VIII.23, this intermediate-aged galactic cluster will blow your mind in large aperture.

Although visible in binoculars, as aperture increases the field explodes into about 100 stars in a highly compressed, rich cloud. Although not visited often, NGC 6940 is on many observing challenge lists. Use low power to get the full effect of this stunning starfield!

Now, move on to Aquila and look at the hot central star of an interesting planetary nebula – NGC 6804 (RA 19 31 35 Dec +09 13 32). You’ll find it almost four degrees due west of Altair. Discovered by Herschel and classed as open cluster H VI.38, it wasn’t until Pease took a closer look that its planetary nature was discovered. Interacting with clouds of interstellar dust and gases, NGC 6804 is a planetary in decline, with its outer shell around magnitude 12 and the central star at about magnitude 13. While only larger telescopes will get a glimpse of the central star, it’s one of the hottest objects in space – with a temperature of about 30,000 K!

While you’re out under the stars, be sure to keep an eye open for the fast moving members of the Alpha Aurigid meteor shower whose radiant is in the northeast near Capella. Activity started just two days ago and will last through the next week. Here’s wishing you clear skies and a great weekend!!

This week’s awesome images are: NGC 6823/6820 – Credit: Palomar Observatory, courtesy of Caltech, Hickson Compact Group 87 – Credit: Palomar Observatory, courtesy of Caltech, NGC 7016/17/18 – Credit: Palomar Observatory, courtesy of Caltech, and NGC 6940 and NGC 6804 – Credit: Palomar Observatory, both courtesy of Caltech.

Greetings, fellow SkyWatchers! Are you psyched up for tonight’s Pleiades occultation? I am! While the Moon often passes near the ancient cluster, it’s not often we get to enjoy such a great event so well placed at a comfortable time of the year. This weekend we’ll be watching for ISS passes, reaching for the “Ring”, visiting Andromeda, and taking on two new Herschel 400 studies. Time to get out your telescopes, spotting scopes and binoculars and head out into the night because…. Here’s what’s up!

Friday, September 19, 2008 – On this day in 1848, William Boyd was watching Saturn – and discovered its moon Hyperion. Also today in 1988, Israel launched its first satellite. And don’t forget…t his evening will feature possibly the best occultation of the Pleiades by the Moon this year, so be sure to check with IOTA for details!

How long has it been since you’ve watched the ISS pass overhead, or seen an Iridium flare? Both are terrific events that don’t require any special equipment to be seen – even in the daytime! Be sure to check with www.heavens-above.com for accurate times in your location – and enjoy. While you’re out SkyWatching, be sure to have a look for Spica on the southwestern horizon after sunset. You just might discover a few planets joining the show!

When skies are dark, it’s time for us to head directly between the two southernmost stars in the constellation of Lyra and grab the “Ring.” What summer would be complete without it?

Discovered by French astronomer Antoine Darquier in 1779, the Ring Nebula was cataloged later that year by Charles Messier as M57 (RA 18 53 35 Dec +33 01 45). In binoculars the Ring will appear as slightly larger than a star, yet it cannot be focused to a sharp point. To a modest telescope at even low power, M57 turns into a glowing donut against a wonderful stellar backdrop. The accepted distance to this unusual structure is about 1,400 light-years, and how you see the Ring on any given night is highly dependent on conditions. As aperture and power increase, so do details, and it is not impossible to see braiding in the nebula’s structure with scopes as small as 8″ on a fine night, or to pick up the star caught on the edge in even smaller apertures.

Like all planetary nebulae, seeing the central star is considered the ultimate achievement in viewing. The central itself is a peculiar bluish dwarf which gives off a continuous spectrum, and might very well be a variable. At times, this shy, near 15th magnitude star can be seen with ease with a 12.5″ telescope, yet be elusive to even 31″ in aperture weeks later. No matter what details you may see, reach for the “Ring” tonight. You’ll be glad you did.

Saturday, September 20, 2008 – On this night in 1948, the 48″ Schmidt telescope at Mt. Palomar was busy taking pictures. Its very first photographic plate was being exposed by the same man who ground and polished the corrector plate for this scope – Don Hendricks. His object of choice was reproduced as panel 18 in the Hubble Atlas of Galaxies, and tonight we’ll join his vision as we take a look at the fantastic M31, the Andromeda Galaxy.

Seasoned amateur astronomers can literally point to the sky and show you the location of M31, but perhaps you have never tried to find it. Believe it or not, this is an easy galaxy to spot even under the moonlight. Simply identify the large diamond-shaped pattern of stars that is the Great Square of Pegasus. The northernmost star is Alpha, and it is here we will begin our hop. Stay with the northern chain of stars and look four fingerwidths away from Alpha for an easily seen star. The next along the chain is about three more fingerwidths away… And we’re almost there. Two more fingerwidths to the north and you will see a dimmer star that looks like it has something smudgy nearby. Point your binoculars there, because that’s no cloud – it’s the Andromeda Galaxy!

Now aim your binoculars or small telescope its way… Perhaps one of the most outstanding of all galaxies to the novice observer, M31 spans so much sky that it takes up several fields of view in a larger telescope, and even contains its own clusters and nebulae with New General Catalog designations. If you have a slightly larger telescope, you may also be able to pick up M31’s two companions – M32 and M110. Even with no scope or binoculars, it’s pretty amazing that we can see something – anything! – that is over two million light-years away!

Sunday, September 21, 2008 – On this date in 2003, the Galileo spacecraft bravely entered the atmosphere of Jupiter as it completed its final mission. Launched in 1989 and orbiting the giant planet since 1995, the hugely successful Galileo taught us much about Jupiter’s lethal radiation belts, magnetic field, atmosphere, and moons – but it had one last command to execute: self-destruction. Although it was still performing flawlessly (despite its lack of fuel and with its instrumentation badly scarred by radiation), scientists feared it might contaminate other possible life-sustaining moons such as Europa, and the decision was made to aim it into Jupiter’s certain oblivion. We salute its final moments!

And what was Sir William Herschel doing on this date a couple of centuries ago? You can bet he was out telescoping; and his discoveries on this night were many. How about if we take a look at two logged on September 21 which made the Herschel “400” list?

Our first stop is northern Cygnus for NGC 7086 (RA 21 30 30 Dec +51 35 00). Located on the galactic equator about five degrees west of Beta Cephei, our target is an open cluster. At magnitude 8.4, this loose collection will be difficult for the smaller scope, and show as not much more than an arrow-like asterism. However, larger scopes will be able to resolve many more stars, arrayed in long loops and chains around the brighter members. Although it’s sparse, NGC 7086 has been studied for metal abundance, galactic distance, membership richness, and its luminosity function. Be sure to mark your notes for H VI.32, logged by Herschel in 1788.

Now hop on over to Andromeda for NGC 752 (RA 01 57 41 Dec +37 47 06). You’ll find it just a few degrees south of Gamma and in the field north of star 56. Located 1300 light-years away, there’s a strong possibility this cluster was noted first by Hodierna before being cataloged by Herschel on this night (1786). At near magnitude 5, this “400” object is both large and bright enough to be seen in binoculars or small telescopes, and people have often wondered why Messier did not discover it. The star-studded field containing about 70 members of various magnitudes belong to H VII.32 – a very old cluster which has more recently been studied for its metallicity and the variations in the magnetic fields of its members. Enjoy them both tonight! Sir William did…

Until next week, I will you clear skies and happy hunting!

This week’s awesome images are: M57 “Ring Nebula” – Credit: NOAO/AURA/NSF, 48″ Schmidt Scope (Drawing by Russell Porter) – Credit: Palomar Observatory courtesy of Caltech, The Andromeda Galaxy – Credit: Anonymous, Artist’s concept of Galileo – Credit: NASA, NGC 7086 – Credit: Palomar Observatory, courtesy of Caltech and NGC 752 – Credit: Palomar Observatory, courtesy of Caltech. Our many thanks!

Be sure to mark your calendar for tomorrow night. For lucky observers in northeastern North America, eastern Canada, and western Europe, the evening of September 19-20, 2008 is your opportunity to watch the face of the peaceful gibbous Moon glide across the ancient blue beauty of the Plieades…

On Friday night, September 19, 2008, observers in northeastern North America, eastern Canada need to be outdoors and ready when the Moon begins to rise low in the east-northeast. If you live in Western Europe, the event takes place high in the sky just before dawn on the morning of September 20th. Don’t come alone, bring binoculars or a telescope with you, because this is your chance to see the stars first disappear behind the Moon’s bright limb and then reappear on the dark side.

Although we rarely call the Pleiades by name, let’s try them on for size. The brightest is Alcyone at magnitude 2.86, followed by Atlas at 3.62, Electra at 3.7, Maia at 3.86, Merope at 4.17 and Taygeta at magnitude 4.29. While it may be a bit difficult for a novice to read the occultation information, please check this occultation information at IOTA where you can get precise times for your location for the disappearance and reappearance of each individual star.

To help you understand a bit further, let’s choose Alycone. Click on the September 20th category for the US and let’s choose Cleveland, Ohio. Alycone would disappear behind the bright limb of the Moon at 02:14:09 UT (which would be 10:14:09 pm, September 19th). Alycone will re-emerge from behind the dark edge of the Moon at 02:45:47 UT (or 10:45:47 pm). See? It’s not that hard! The most difficult part is simply figuring out the universal time difference is all it takes, and there’s even a website for that!

While you can watch the event without any optical aid, the Moon will overpower the stars. Use a card or something held at arm’s length to help diminish the glare. However, if you’re serious? A telescope is the key to really enjoying this event. It is great fun to keep tabs on each star as it slowly approaches the lunar limb and then just winks out! Timing of these events is critical, because it helps astronomers to further understand lunar features. How? By assessing times, astronomers are able to determine if there are peaks and valleys that we simply do not know about. For example, a bright star may wink off and on several times before it finally disappears behind a hidden lunar mountain… and the same holds true when it reappears.

Although the Moon frequently encounters the Pleiades on each monthly journey across the ecliptic plane, it’s infrequent that we have such a great opportunity to watch several occultation events in a well-placed area of the sky during a comfortable time of the year. Enjoy this great event…

Images accompanying this article are the Pleiades Occultation by John Cudworth and the annotated image of the Plieades by David Malin, courtesy of the Anglo-Australian Observatory/University of Edinburgh.