Indus

Indus

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The constellation of Indus was originally created by Petrus Plancius from the observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere. Indus’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603. It survived the years to become one of the 88 modern constellations recognized by the International Astronomical Union. Indus is located south of the ecliptic plane and covers approximately 294 square degrees of sky. It consists of three main stars in the primary asterism and has 16 stars with Bayer/Flamsteed designations. Indus is bordered by the constellations of Microscopium, Sagittarius, Telescopium, Pavo, Octans, Tucana and Grus.

Since the constellation of Indus wasn’t created until late in the sixteenth century, there isn’t any ancient mythology associated with its stellar patterns. However, Indus is meant to represent as a native – perhaps one met by the Dutch explorers on their travels in the Indies or Africa. It is also believed that Johannes Bayer wish to honor the native American Indians as well, so Indus was thus included in his works.

For observers, let us begin with binoculars the brightest star – Alpha Indi – the “a” symbol on our map. Who know exactly how stars sometimes get their names, but you’ll often find this star is called ” the Persian” on some lists. Located about 101 light years from our solar system, Alpha is super-metal-rich, K-type orange giant star that outshines our own Sun by about 62 times. Have a telescope? Be sure to take a look at “the Persian”. You’ll find it has a pair of 12th and 13th magnitude red dwarf star companions!

Now hop to the center of this Y-shaped asterism and have a look at Theta Indi. That’s right! Another binary star. Located about 91 light years from Earth, you’ll find a very nice double star here, with components that are easy to separate with a small telescopes. The primary is fifth magnitude and the secondary is magnitude seven.

Time to follow the branch of the Y southwest and have a look at Beta Indi – the “B” shape on our map. While the rest of the stars we’ve look at so far were fairly near – Beta isn’t. Located at minimum of 600 light years away, Beta Indi is a very massive and luminous star of the orange K-type classification. Take a look through the telescope, too… Because you’ll find that Beta also has a 12th magnitude visual companion whose distance is unclear. At the southeast end of the Y branch is Delta, whose orbital mechanics have been closely studied.

Now drop south for Epsilon – the backward “3”. Epsilon Indi is one of the closest stars to Earth, approximately 11.82 light years away. Epsilon is a dwarf star – only about 75% the size of our own Sun – and very similar in respects to movement, corona and gravity. Even its photosphere and metallicity is a close comparison. In 1847, Heinrich Louis d’Arrest was the first to notice that Epsilon had moved right along compared to its charted 1750 position, and it has been measured about every 100 years since. Astronomers have since placed it in what is called the Epsilon Indi Moving Group of Stars – a stellar association of about 16 members that quite likely formed about the same time in the same location.

Of course, being so close means Epsilon was also the object of many signal studies, including radio signals and lasers – but unfortunately, no signals were ever returned. Even though we haven’t gotten a reply, it still leads the list of 17,129 nearby stars most likely to have planets that could support complex life. With good reason! In January 2003, astronomers announced the discovery of a brown dwarf with a mass of 40 to 60 Jupiter masses in orbit around Epsilon Indi at a distance of at least 1500 astronomical units… And what’s more, it’s actually a binary brown dwarf star! Although measurements of the radial velocity of Epsilon Indi appear to show the presence of a planetary companion with an orbital period of more than 20 years, so far no space telescope yet has been able to prove its existence.

Now it’s time to take a telescope tour of Indus. Our first object is IC 5152 (RA 22:02.9 Dec -51:17). Hanging out about 3 million light years away, this irregular dwarf galaxy could very well be an outlying member of our own Milky Way local group of galaxies. At roughly magnitude 11, look for some patchy details, including a line of sight star caught on its edge.

Next up? NGC 7090 (RA 21:36.5 Dec -54:33). Even though billed at near magnitude 11, this soft spoken spiral galaxy is low surface brightest to the eye – but an astrophotographer’s dream. It has a fantastic h-alpha halo! Look for several scattered stars in the same field, including a very wide equal optical pair lying to the east.

Hop now to NGC 7083 (RA 21:35.7 Dec -63:54). At magnitude 12, this galaxy is meant for larger telescopes, but this barred galaxy is also highly studied for its spiral galaxy structure. It is considered a grand design and well worth taking some time on!

Last for now? NGC 7049 (RA 21:19.0 Dec -48:34). Although on the small side, NGC 7049 is a bit brighter than our last study at magnitude 11. It is an early-type spiral galaxy and also a target of the Hubble Space telescope, which studied it for its inner polar disc properties. You’ll find it about about 15′ east of a bright, yellowish star (6.5 magnitude) and the surface brightness will allow you to do a little more serious studying!

Source: Wikipedia, ESO
Chart courtesy of Your Sky.

Ready… Willing… And Abell! The Perseus Galaxy Cluster by Kent Wood

The Perseus Galaxy Cluster - Kent Wood

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What you’re looking at isn’t a Hubble Deep Field image peering into the furthest reaches of space. What you’re seeing is a galaxy field photographed with a 12.5″ telescope located right here on planet Earth aimed 2 degrees east of Algol. It’s a challenging galaxy cluster in Perseus known as Abell 426…

So, what exactly is it? The Perseus galaxy cluster consists of about 500 members located some 250 million light-years away. They are diffuse, they are faint, and they are dominated by radio source Perseus A – Seyfert galaxy NGC 1275. Just contained in this area alone is more than 200 trillion solar masses! In the X-ray band, no galaxy cluster out there shines brighter.

Although George Abell died several years ago, one of the most enduring legacies he left astronomy is a catalog of galaxy groups that he compiled in the 1950’s. Since that time, it has been the goal of almost all backyard astronomers with larger telescopes to conquer as many of the Abell list as we possibly can, following in his footsteps hoping to catch just a glimpse of what he once saw using the plates of Palomar Observatory Sky Survey (POSS). Although our human eyes can never match what a camera can see, so much progress has been made since Abell’s time that revealing true science is within the grasp of the amateur.

Things that we can’t see visually, like gravitationally lensed quasars are revealed – interactions of dark matter and gas. In 2003, the Chandra X-ray telescope took a very close look at radio source 3C 84 and found it was blowing bubbles of plasma into the core of the cluster. To Chandra’s “eyes”, they appeared as holes in the image – pushing away the X-ray emitting gas. What exactly are they? Try relativistic particles – a particle moving at the speed of light. In astrophysics, jets of relativistic plasma are produced by the centers of active galaxies and quasars… and my friends? That can be captured in photographs, just like Kent’s.

According to the Chandra research team; “A similar front may exist round both inner bubbles but is masked elsewhere by rim emission from bright cooler gas. The continuous blowing of bubbles by the central radio source, leading to the propagation of weak shocks and viscously-dissipating sound waves seen as the observed fronts and ripples.” This resulted in the deepest tone ever detected from the Cosmos – a tone no human will ever hear. Or will it? Abell 426 calls loudly… And it calls very loudly to some of us.

A few years ago I decided to tackle the Perseus Galaxy Cluster with a 12.5″ telescope, too. But, I am a visual astronomer. There will never be a day when I can see with my eyes what Kent has captured with a 12.5 Planewave CDK, but perhaps those of you who hear the call of Abell 426 would like to know what it’s like to step into the heart of a galaxy cluster? This is from my personal observing reports:

“So, do I always do what you tell me to? Well, yeah! You are my Master… And if you tell me to go walk outside and look to the northwest? I will obey. And if you tell me the skies will clear? I will listen. If you hand me a dark skies night, one with 6.5 visibility and 7/10 stability… Put a 12.5 scope beneath my hands. If you give me a map… I will walk with you to the stars. If you give me a notebook and a mechanical pencil… I will study. And if you give me a galaxy field? I will do my best to make you proud. When I pulled the dob out, I could only see Perseus. Why is it that things happen this way? The cold wind would take a bite out of me quickly if I used the west side yard… But Algol is at maximum and it was simply all I could see! Why would I want to chase after an old study when the east sky is filled with new ones? Why? I don’t understand why! All I understand is that tonight I want Abell 426. Starting at Algol, I shift into my “weird” study mode and stop to ride the diffraction waves. I know I’m rather strange, but I’d really like to know if I can catch a spectroscopic difference between Algol at maximum and Algol at minimum. Yeah, I’m sure I’m probably being kinda’ dumb because my equipment is so primitive… But I’m curious. OK? Making my notes, I put the diffraction grating away once again. I learn. Therefore I am. Now, let’s rock and roll…

Abell 426 has been a longstanding favourite of mine. It is a curious galaxy cluster in the respect that the finer the night, the more galaxies will reveal themselves. While tonight is not the most exceptional night I’ve ever encountered, it is a fine one for galaxy studies. Brushing Algol away in the eyepiece, I close my eyes and sing along with the music for several minutes, mentally and visually preparing myself for faint studies. I am becoming accustomed to the cold, and when my eyes are ready? It’s time to go to the finder, for the first study lays right in the field with a star.

The NGC1224 requires wide aversion. It is faint, round, and shows some concentration toward the nucleus with patience. Held indirect, this small galaxy has a UGC-like signature. Next stop on the hop is the NGC1250. Very diffuse and small…. Also requiring wide aversion. While allowing the eye to bounce around the field, it is possible to make out a slight north/south tilt to this galaxy that may indicate it to be a spiral. Curiously enough, it is during this motion that a pinprick of a nucleus can be detected. Pushing on toward the heart of the Perseus Galaxy cluster, my next destination is a chain of three. First study mark is the NGC1259. Whoa! Extreme aversion here, boss… Very, very diffuse and faint. It can only be caught by focusing attention on the tiny star in the westward drift. The NGC1260 only requires slight aversion, however. It is small and somewhat diffuse. Definitely ovoid in structure… And definitely the easiest to see of these three! The NGC1264 also requires very wide aversion. Very faint and diffuse. Very round…. Very challenging! Now, triangulating with this series, it’s time to go for the NGC1257. Very faint, diffuse and small with a concentration toward the core, it holds a little surprise. There’s a tiny star at the northeast end that allows one to see upon wide aversion that the galaxy itself seems to migrate to the northeast/southwest. Excellent!

From here I have the option of continuing on the same trajectory or doing a lateral “thing”. I find myself grinning, because I know from past experience that my maps don’t always reveal everything there is to be seen in such a cluster. I’ll have to be awfully careful when going toward the heart of Abell 426, or I’ll lose my sense of direction and darn well get lost! Oh well, eh? It wouldn’t be the first time I’ve been told to do so.

The NGC1271 skirts the most populated part of this Abell cluster. If I’ve got the right one, we’re talking about a super wide aversion, very faint, very small patch that is barely capturable. Even patience and my own set of tricks can draw nothing more than a slightly regular contrast change in this area. Next up is an extremely challenging triple. The NGC1267, NGC1268 and NGC1269 are three incredibly tiny, very diffuse round gems that would be indistinguishable at lower power. Phew! This little trio is really bad… I couldn’t even qualify these as “hairy stars” because they’re so diffuse!

Breathing quietly so I don’t fog anything up, right now I’d just about sell my soul for a cup of chai and a few minutes by the fire. But, I realize that if I stand down now, I’ll lose whatever sense of orientation that I’ve gained. (and that, coming from a blond, is no joke.) I can see the “heart” of Abell 426, and I know how easy it would be to just let go… Enjoy! Not care? Not hardly. (don’t stop, ~T…. just don’t stop.)

NGC1273 is faint. It requires aversion, but the brighter core region holds up to indirect vision. The NGC1272, is also round… Almost planetary in appearance. This is a galaxy that is definitely a player in this field!! The NGC1270 is very diffuse and a wide aversion. It contains a very small, almost stellar nucleus. Now the cluster is getting thick and tight. Can I do this and do it correctly? Hey, hey… Let’s give it a go. I can’t do anything worse than be wrong, eh? NGC1279 is faint, diffuse, but holds. It stretches just every so slightly, like a thin smear held at slight aversion to the north/south. It is even with no nucleus present. The NGC1274 is very faint and very diffuse and even. It is best seen while concentrating on the NGC1279. Just an incredibly misty oval. The NGC1275… (holy sh*t! one i can see!!) is very bright compared to all the previous studies. Most definitely has a bright and easily held direct nucleus.

And now I’m laughing out loud, because these little puppies are everywhere. Much like studying Virgo clusters, once you see a bright galaxy, what seems like swarms come out to play all around! I guess it’s time for me to bow gracefully out of the middle of this dance before I make a great fool of myself. Let’s just head back toward the outskirts and although these might not be considered to be part of the Abell 426, at least I stand a better chance at identification!

Going for a pair, I find the NGC1282 to be diffuse, slight in size and quite ovoid. Very even in structure, no hint of a nucleus even a full avert. The companion, NGC1283, is very diffuse and I probably wouldn’t have even caught it except for that I was looking at some small field stars that triangulate in this area when it made its’ foggy appearance. Now for the NGC1294 and NGC1293… Wide aversion shows two round fuzzies with prickly nucleus structure. The pair reminds me of two impossibly small “gone to seed” dandelions waiting to be scattered on the cosmic winds… Huh? Listen. When I start writing junk like that in my notes, I’m either high on photons or nearing hypothermia. Or maybe both, eh?”

If the Perseus Galaxy cluster calls to you in a low tone… listen. It called to George Abell in 1958 and it called to Kent Wood just a few days ago. We’re glad it did…

Many, many thanks to AORAIA member Kent Wood for his superb image and allowing us to share what our eyes cannot see!

Full Rez Image

Hydrus

Hydrus

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The constellation of Hydrus was originally created by Petrus Plancius from the observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere and should not be confused with its more northerly counterpart – Hydra. Hydruss’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603. It survived the years to become one of the 88 modern constellations recognized by the International Astronomical Union. Hydrus is a southern circumpolar constellation and covers approximately 243 square degrees of sky. It contains 3 major stars which make up its asterism and 19 stars which have Bayer/Flamsteed designations. Hydrus is bordered by the constellations of Dorado, Eridanus, Horologium, Mensa, Octans, Phoenix, Reticulum and Tucana. It can be seen by observers located at at latitudes between +8° and ?90° and is best visible at culmination during the month of November.

Because Hydrus wasn’t visible to the ancient Greeks or Romans, no mythology surrounds this constellation. It is, however, just another example of how constellation names and figures can sometimes repeat themselves, like Ursa Major and Minor, Canis Major and Minor, Pegasus and Equuleus, Leo and Lynx… Perhaps the ancient Maori had legends about this handful of stars! To them, the Hydrus was the water snake who killed crocodiles by entering into their mouths and killing them from the inside…

Let’s begin our binocular tour with the second brightest of the stars – Alpha Hydri – the “a” symbol on our map. Once upon a time in the year 2900 BC, this happy little F class dwarf star had the honor of being the southern pole star. Thanks to the precession of the equinoxes, it has long since moved away, but continues to be of interest as it gears up to become a red giant star. Rotating completely on its axis about every 26 hours, all of Alpha’s exterior activity happens acoustically rather than magnetically. Why? Because 71 light year distant Alpha has a high metal content!

Now, drop south for Beta Hydri – the “B” symbol on our map. In binoculars you’ll see a nice visual double star. Beta is located 24.4 light years from our solar system and right now serves the distinction of being the brightest star closest to the south celestial pole. What’s special about it? What you’re looking at is nearly a duplicate of our own Sun. While it is just slightly larger and brighter, Beta is most definitely a subgiant near or at the end of its hydrogen fusing life – on its way to becoming a red giant no larger than the orbit of Earth. Its maximum rotation period is 29 days, very near to that of the 24 day cycle of Sol and its evolutionary fate appears to be similar – a “one day” white dwarf star.

Hop north and east for Gamma Hydri – the “Y” shape on our map. If you think you’re seeing red compared the the soft yellow-white of the other stars – you’re right. Gamma is a luminous class M red giant star that has signed off core hydrogen fusion and is approaching the end of its life span. While it is not terribly large – not even the size of the orbit of Mercury compared to our Sun, Gamma puts out some real stellar luminosity – shining 650 times brighter than Sol. This may be because it is firing up its helium to fuse carbon and oxygen… or it may have depleted its helium and is about to toss off its outer envelope and become a dead, white dwarf!

Before we move on, let’s head back north… Stopping first to pay our respects to visual double star Pi 1 Hydri – a non-interacting pair of 6th magnitude giants. Look closely because Pi 1 is red and Pi 2 is orange! Now, hop east to Eta 2 – the “n 2” symbol on our map. What’s so special about Eta 2? First off, Eta Hydri is a double star – a true binary star consisting of a blue-white dwarf called Eta 1 and a yellow giant star, Eta 2. But hey, that’s not what really fun. What’s really run is there is a giant planet orbiting around Eta 2! It’s about 217 light years from Earth and it goes by the very unromantic name of HD 11977 b. Sure, it’s about six and a half times the size of Jupiter, which puts it right up there at dead star size… But hey! It’s a planet! This means at least a few intermediate-mass stars could host substellar companions – either planets or brown dwarfs. When later measured by Doppler, science proved HD 11977 b was clearly within the planetary mass and became the first to be accurately determined.

Are you ready for a true telescope challenge? Hydra isn’t precisely known for bright objects, so our first is IC 1717 (RA 01h 32m 30.0s Dec -67 32′ 12.0″). What is it? Well… nothing. The only thing we really know for sure it that something was there when Dreyer cataloged this position because Dreyer was exceedingly good at his job. Maybe it was a comet… Maybe it was something variable. It never hurts to look!

Just in case you have an small telescope, you might want to try NGC 1466 (RA 03:44.5 Dec -71:41). This 11.5 magnitude globular cluster doesn’t belong to the Milky Way Galaxy… it belongs to the Large Magellanic Cloud. Even that far away, science has been able to spot that it has 44 RR Lyra type variable stars and is every bit as old as the galaxy halo to which it belongs!

For large telescopes, try NGC 1511 (RA 3:59.5 Dec -67:38), too. This ‘object’ is actually a triple set of galaxies whose co-ordinates are so close to one another that they almost appear as one unit. Interacting galaxies? You bet. This galaxy collision is a process that’s been going on for a billion years and will eventually become a giant elliptical galaxy at then end. Chances are NGC 1511 has already absorbed at least one galaxy in its past. According to scientists, “the peculiar optical ridge to the east of NGC 1511 is probably the stellar remnant of a galaxy completely disrupted by interactions with NGC 1511”.

Sources: Wikipedia, Chandra Observatory
Charts Courtesy of Your Sky.

The Hydra Constellation

Hydra West
Hydra East
Hydra East

The sprawling constellation of Hydra was one of the 48 constellations listed by Ptolemy and endures today to be the largest of the 88 modern constellations adopted by the International Astronomical Union. Spanning an incredible 1303 square degrees of night sky and containing 17 primary stars in the asterism, Hydra contain 75 stars with Bayer/Flamsteed designations. It is bordered by the constellations of Antlia, Cancer, Canis Minor, Centaurus, Corvus, Crater, Leo, Libra, Lupus, Monoceros, Puppis, Pyxis, Sextans and Virgo. Position south of the ecliptic plane, Hydra is visible to all observers at latitudes between +54° and ?83° and is best seen at culmination during the month of April.

In mythology, Hydra represents the Snake – not much of a stretch of the imagination given all the twists, turns and distance this constellation takes across the sky. According to legend, Apollo sent the Raven, Corvus, off with the Cup (Crater) to fetch a drink. When the Raven spent his time waiting for a fig to ripen instead of returning with Apollo’s refreshment, he realized he’d made a mistake and grabbed a water snake to offer to the sky god as atonement for his tardiness. Infuriated, Apollo tossed the whole lot of them into the sky where they remain until this day… Some legends also refer to Hydra as one of the many labors of Hercules, too!

Shall we begin with a binocular tour of Hydra? Then let’s start first with the small asterism of stars which marks the “head” of Hydra located between bright stars Regulus and Procyon. When you’ve picked out this distorted circlet, focus your attention on the northernmost of these stars – Epsilon – the backward “3” on our map. While to binoculars it might seem rather ordinary, Epsilon is actually a fantastic multiple star system with at least five members! The primary is a yellow-white giant star with a white subgiant star orbiting so close that it is considered a spectroscopic binary star. A bit further away is another binary pair, the G and F star… and further away yet is a class M dwarf star. Be sure to take out your telescope and have a look….

Now move southeast for the brightest star in Hydra – Alpha – the “a” symbol on our map. Its name is Alphard and it is located about 175 light years away from Earth. Shining in a very soft orange color, this giant star reaches temperatures of about 4000 degrees Kelvin and if at home in our solar system would be about 400 times brighter than our Sun. What makes Alphard unique? Its barium content. At one time Alphard, too, was a binary star, but its massive companion is long gone. Alphard happily collected its by-products of nuclear fusion and left us with evidence of what once was!

Keep your binoculars handy and use the two points of reference you’ve just learned to find our next target – Messier 48. By connecting Epsilon and Alpha as the base of an imaginary triangle with the top pointed southwest, aim your binoculars at the apex and behold one very nice – and very bright – open star cluster. Discovered by Charles Messier in 1771 and also cataloged as NGC 2548, you might even be able to distinguish this stellar field as a hazy spot unaided from a dark sky location. With an estimated age of about 300 million years, you’ll see a very large group of about 50 stars which can resolve into as many as 80 members in larger telescopes. When you see M48, you can thank Caroline Herschel for fixing Messier’s position mistake on this one!

Hop along to Lambda Hydrae – the upside down “Y” on our map. Lambda is a visual double star in binoculars, but it is also a true spectroscopic binary star as well. As you continue south, then east and pass by Xi (the squiggle), keep in mind Xi is unique, too. Xi is an evolved giant star with solar-like oscillations… the very first time science has proved the existence of vibrations in a giant star 10 times the size of our Sun! If you place Xi to the western edge of the field in binoculars, you’ll also see 5th magnitude Beta Hydrae, too. Seeing two there instead of one? You should. Beta is a visual double star and the pair are only separated by about half a magnitude.

Now head northeast towards Gamma, but stop by Messier 68 along the way. This class X globular cluster was discovered by Charles Messier on April 9, 1780, but was resolved into stars by Sir William Herschel who said; “A beautiful cluster of stars, extremely rich, and so compressed that most of the stars are blended together; it is near 3′ broad and about 4′ long, but chiefly round, and there are very few scattered stars about.” M68 will look like a small, round fuzzy in binoculars, but larger telescopes will resolve this 33,000 light-year distant Milky Way resident out!

Are you ready for Gamma Hydrae? It’s the “Y” shape on our map. If you got lost, just use the lower two stars of Corvus to point east towards it. Gamma is located about 132 light years away from our solar system and shines approximately 105 times brighter than Sol. In the not-to-distant past, Gamma decided to shut down its hydrogen fusion factory, which means it may possess a dead helium core. What’s in Gamma’s future? Chances are it will grow larger and less luminous as the core shrinks – then it will fire up to fuse carbon and oxygen. When it does it will become six times brighter and five times bigger! If you’re looking with a telescope and see another star there, you’re right… but it’s an optical companion.

To the east of Gamma is R Hydrae. Now here is one classy variable star! Located about 2000 years away from Earth, R Hydrae’s changes take a period of 389 days to happen, but they happen in a big way. The magnitude of this crazy star jumps from a very dim and telescopic only 11.0 to an easy unaided eye 3.2! R is the third Mira-type variable discovered and may have been noted as early as 1662 by Johannes Hevelius. R Hydra is also special because it has a “declining period” – it has changed its times by 100 days in the last couple of hundred years. So what’s happening? A helium shell is building up around the exterior – just waiting for the day to reach a critical mass and ignite, creating more carbon and oxygen. This is called a “helium shell flash” and it signals the end of life for the giant star. Eventually the layers will just expand into space and the carbon-oxygen core will shine as a white dwarf star. Look around while you’re there… Because you just might spot a companion!

Now drop almost due south for Messier 83 (RA 13:37.0 Dec -29:52). In binoculars this superb spiral galaxy will appear as a soft round glow, but telescopes will reveal wonderful spiral galaxy structure (dependent on observer latitude). With a classification somewhere between a normal and barred spiral galaxy, large telescopes can expect to at least see three traces of spiral arm structure. For astrophotographers, you’ll find terrific star forming regions will appear and dark dust lanes follow the spiral structure throughout the disk.

Ready to do a telescope object in Hydra? Then look no further than NGC 3242 (RA 10:24.8 Dec -18:38). This 8th magnitude planetary nebula is best known as the “Ghost of Jupiter” for its magnificent size! Be sure to look for a double halo structure and the 11th magnitude central star. Even small telescopes will catch a faint blue color to this superb object!

For larger telescopes, let’s try some galaxies. First off, NGC 3621 (RA 11:18.3 Dec -32:49) located about about 3 degrees west/southwest of Xi. You’ll find this fairly larger and bright spiral galaxy sitting inside a box of faint stars! Need a pair of galaxies? Then try NGC 3923 and NGC 3904 (RA 11 h 51 min Dec – 28 48′). Use low magnification and a wide field eyepiece to capture this spiral and elliptical galaxy in the same view.

There’s plenty more deep sky in the constellation of Hydra to be explored, so be sure to get a good star chart and charm the “Snake”!

Sources: Chandra Observatory, Wikipedia
Charts Courtesy of Your Sky.

The Horologium Constellation

Horologium chart (IAU chart). Credit: IAU

If you’ve got a clear view of the skies, and happen ti live in the southern hemisphere, there’s a relatively obscure constellation you should probably check out. It’s known as Horologium, a region of the sky that is named after an important historic personality, one who is largely responsible for how we measure time.

The constellation of Horologium was one of 14 created by Nicolas Louis de Lacaille to chart southern hemisphere skies. Originally named “Horologium Oscillitorium” to honor Christiaan Huygens – the inventor of the pendulum clock – it was later shortened to its present named when adopted as one of the 88 modern constellations by the IAU.

Horologium spans 249 square degrees of sky and consists of 6 mains stars in the asterism, with 10 Bayer/Flamsteed designated stars. It is bordered by the constellations of Eridanus, Hydrus, Reticulum, Dorado and Caelum. Horologium is visible to all observers at latitudes between +30° and ?90° and is best seen at culmination during the month of December.

Constellation Horologium
The constellation Horologium, as seen by the naked eye in the southern hemisphere. Credit: AlltheSky.com

Horologium was named to honor Christiaan Huygens, the Dutch mathematician, astronomer and physicist. While traveling in the southern hemisphere and charting the heavens, Nicholas de Lacaille (who loved all things science) found this dim constellation reminded him of Huygen’s newly invented pendulum clock.

Huygens clock incorporated the first harmonic oscillator – increasing the accuracy to within 15 seconds per day. His “horological innovation” so impressed Lacaille that he found the pattern for this invention in the stars.

Horologium is bordered by five different constellations: Eridanus (the Po River), Caelum (the chisel), Reticulum (the reticle), Dorado (the dolphinfish/swordfish), and Hydrus (the male water snake).

Spring driven pendulum clock, designed by Huygens, built by instrument maker Salomon Coster (1657),[96] and copy of the Horologium Oscillatorium,[97] Museum Boerhaave, Leiden
Spring driven pendulum clock, designed by Christiaan Huygens (1657) and copy of the Horologium Oscillatorium,  Museum Boerhaave, Leiden. Credit: Flickr/Rob Koopman

The official constellation boundaries are defined by a twenty-two sided polygon. Covering a total of 249 square degrees, Horologium ranks 58th in area out of the 88 modern constellations.

With almost no bright stars to claim, stargazing at Horologium can be a bit tricky. But with binoculars, a telescope, and a chart, there are plenty of opportunities for some picturesque views. Let’s start by taking a look in binoculars with Alpha Horologii – the “a” symbol on our map.

Located about 193 light years from Earth, this very normal K1 orange giant star – quietly fusing its core helium into carbon and oxygen. Nearby is Delta, the “8” symbol. It, too is rather ordinary. Delta is a spectroscopic binary star, located about 175 light years away.

So, with very little in the constellation in the way of stars, what is there to do with a telescope? First of all, there’s NGC 1261 (RA: 03:12:15.3; Dec: -55:13:01). This 8th magnitude globular cluster is very well condensed and is at home in a very picturesque field. Small wonder it made the Caldwell list at number 87. Look for a very bright core region and well resolved chains of stars at the edges of this pretty star cluster.

Globular Cluster NGC 1261: SOFI infrared multimode instrument on the ESO 3.58-m New Technology Telescope at La Silla, Chile. Credit: ESO
Globular Cluster NGC 1261 as observed from the New Technology Telescope at La Silla, Chile. Credit: ESO

For larger telescopes, try NGC 1512 (RA 4:03.9 Dec -43:21). At slightly brighter than magnitude 11, this barred spiral galaxy belongs to the Dorado group and is located about 30 million light years away. While you won’t find much details here, NASA’s Galaxy Evolution Explorer show spiral galaxy NGC 1512 sitting slightly northwest of elliptical galaxy NGC 1510.

The two galaxies are currently separated by a mere 68,000 light-years, leading many astronomers to suspect that a close encounter is currently in progress. The overlapping of two tightly wound spiral arm segments makes up the light blue inner ring of NGC 1512. Meanwhile, the galaxy’s outer spiral arm is being distorted by strong gravitational interactions with NGC 1510.

Another challenge? Then try NGC 1433 (RA 3:42.0 Dec -47:13). This magnitude 10 galaxy is an example of a ringed barred spiral. While physically you may only notice a bright nucleus and the soft bar, the stars orbiting the disk of this galaxy shows its internal motions photographically. A small elliptical ring can develop near the nucleus – blue proof of star formation. Always keep a watch, because this galaxy had a supernova event in 1985.

Source: Wikipedia
Chart Courtesy of Your Sky.

Hercules

Hercules

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The constellation of Hercules belongs to one of the 48 originals plotted by Ptolemy and has survived time to become one of the 88 modern constellations adopted by the International Astronomical Union. Spanning an impressing 1225 square degrees of sky and containing 22 stars in the asterism, it has 106 Bayer/Flamsteed designated stellar designations. Hercules is bordered by the constellations of Draco, Bootes, Corona Borealis, Serpens Caput, Ophiuchus, Aquila, Sagitta, Vulpecula and Lyra. It is visible to all observers at latitudes between +90° and ?50° and is best seen at culmination during the month of July. There is one annual meteor shower associated with Hercules, the Tau Herculids, which peak on or near June 3. The radiant, or point of origin, is near the Hercules/Corona Borealis border and the meteor shower itself last about a month beginning around two weeks before and lasting about two weeks after the peak date. Most of these meteors are quite faint and at maximum, expect to see no more than 15 per hour average.

The mythology surrounding Hercules is a long and very colorful one. He was considered the greatest of all heroes – both Greek and Roman. The legendary strong man was supposed to be the son of Zeus; immortal, yet forever challenged by Hera by his circumstance of birth. His tasks were many: killing a lion with a hide that could not be punctured, destroying the many headed Hydra, cleaning out nasty stables, fighting birds with knife-like feathers, capturing a bull that breathed fire, taming horses that ate flesh, stealing cattle from monsters, stealing golden apples, fighting dragons, snatching a three-headed dog, loosing the love of his life, accidentally killing his teacher and so much more… It is no wonder that Hercules is so often depicted as kneeling in the sky! Even an immortal would be tired from so much… But at last, Hercules earned his place in the stars and he remains there to this day… The fifth largest constellation in the night sky.

Because the constellation of Hercules has no particularly bright stars, it is sometimes difficult to navigate through with binoculars until you learn a few “key” ingredients. There is a large asterism which is fairly easy to recognize that forms a lopsided box, referred to as the “keystone”. The northeast corner is Pi. The northwest corner is Eta. The southeast corner is Epsilon. The southwest corner is Zeta. Always remember when you look at a star chart that north and south are up and down… But east is to the left and west is to the right! To find the “keystone”, let bright Vega guide you…. just start by looking southwest.

Have you found Pi Herculis, yet? If you’re seeing two stars in your binoculars and you’re not sure which one, Pi is the slightly redder and slightly brighter of the pair. Situated about 370 light years from Earth, Pi Herculis is a cool, red supergiant star that was born about 140 million years ago. Although you can’t see it, Pi also has an orbiting substellar companion about 27 times larger than Jupiter there, too! Now, drop south for Epsilon – another binary star. Chances are good this pair of twin stars are almost identical to each other – about twice the size and mass of our Sun – and orbit each other so closely they nearly touch.

Don’t stop moving south. Our next stop is Gamma Herculis, the “8” shape on our map. Gamma is also a very cool star – one with a dead helium core that’s waiting to become a red giant. In maybe 8 million or so years, it will begin to fuse helium into carbon and become much brighter than it is tonight. If you see a faint companion star, it is only an optical one in binoculars – but Gamma is also a genuine binary star.

Next stop? Further south for Alpha – the “a” shape on our map. Now here is a great star! Named Rasalgethi and located about 380 light years away, here we have one of the finest double stars in the night sky. The primary star is a magnificent red class M supergiant that’s over 475 more luminous than our Sun and whose size would fill up our solar system clear out to the orbit of the asteroid belt. But that’s not all… Aim a telescope at Rasalgethi and you’ll see it has a fifth magnitude companion five seconds of arc away. It is also a binary star – an F2 giant with a close orbiting dwarf star companion. Surrounding this whole system is an envelope of gas expelled from the primary star’s incredible solar winds… Enjoy the unusual red and green hues of this colorful double star! And keep watching… Because Rasalgethi is also an irregular variable star – whose brightness changes from magnitude 2.7 to 4.0 within a period of about three months.

Next up? Return to the “keystone” and the northwest corner for Eta – the “n” shape on our map. Shining away about 50 times brighter than our own Sun at a distance of 112 light years, there is nothing particularly impressive about Eta, except where it leads. Begin moving your optics slowly south towards Zeta and you will encounter the “Great Hercules Cluster” – M13! Easily seen in binoculars, sometimes visible to the unaided eye in a dark sky location and absolutely magnificent in any telescope, Messier 13 is perhaps the most famous of all northern globular clusters. Located about 25,000 light years away and home to more than half a million stars, this 12 billion year old system spans no more than 100 light years across. Also known as NGC 6205, this impressive ball of stars was first discovered by Edmund Halley in 1714 and catalogued by Charles Messier on June 1, 1764. If you aren’t impressed, then take the words of Kurt Vonnegut to heart: “”Every passing hour brings the Solar System forty-three thousand miles closer to Globular Cluster M13 in Hercules — and still there are some misfits who insist that there is no such thing as progress.”

Ready for more? Then take another look at Eta and Pi and form an imaginary triangle on the sky using these two stars as the base. The apex is very near where you will find another amazing globular cluster for binoculars or small telescopes – Messier 92. First discovered by Johann Elert Bode in 1777 and independently rediscovered by Charles Messier on March 18, 1781, M92 is a 16 billion year old beauty – formed back at the Milky Way Galaxy’s beginnings. Hiding in there are 16 variable stars and one rare eclipsing binary. What a treat to have two such bright objects so near to one another!

Ready for an alternative binocular tour of Hercules? Then let’s use what you’ve learned. Start by locating magnificent M13 and move 3 degrees northwest – about a binocular field. What you will find is a splendid loose open cluster of stars known as Dolidze/Dzimselejsvili (DoDz) 5 – and it looks much like a miniature of the constellation Hercules. Just slightly more than 4 degrees to its east and just about a degree south of Eta Herculis is DoDz 6, which contains a perfect diamond pattern and an asterism of brighter stars resembling the constellation of Sagitta. Now we’re going to move across the constellation of Hercules towards Lyra. East of the “keystone” is a tight configuration of three stars – Omicron, Nu, and Xi. About the same distance separating these stars northeast you will find DoDz 9. You’ll see a pretty open cluster of around two dozen mixed magnitude stars. Now look again at the “keystone” and identify Lambda and Delta to the south. About midway between them and slightly southeast you will discover the stellar field of DoDz 8. This last is easy – all you need to do is return to Alpha. Move about 1 degree northwest (Rasalgethi will stay in the field) to discover the star-studded open cluster DoDz 7. These great open clusters are very much off the beaten path and will add a new dimension to binocular and fast-telescope observing!

Would you like a challenge? Then go back to M13 with a large telescope and take a look about 40 arc minutes to the northeast for NGC 6207 (RA 16:43.1 Dec +36:50). At near magnitude 12, this small spiral galaxy isn’t for everyone, but it’s always a smile a bonus when you’re in the area, despite the lack of details. Try NGC 6210 (RA 16:44.5 Dec +23:49), too. This bright planetary nebula is suited for all telescopes and takes magnification very well. Look for a blue/green color in larger telescopes, and adding a nebula filter can sometimes reveal some subtle details of a shell around this one. But be sure to take the filter out if you want to catch the central star!

Sources: Chandra Observatory, SEDS
Chart Courtesy of My Sky.

Grus

Grus

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The constellation of Grus was originally created by Petrus Plancius from the observations of Dutch sea navigators Pieter Dirkszoon Keyser and Frederick de Houtman when exploring the southern hemisphere. Grus’ stellar patterns became known when it appeared on a celestial globe in 1597 and was considered a constellation when it was added to Johann Bayer’s Uranometria catalog in 1603. It survived the years to become one of the 88 modern constellations recognized by the International Astronomical Union. Grus is located south of the ecliptic plane and covers approximately 366 square degrees of sky. It is bordered by the constellations of Piscis Austrinus, Microscopium, Indus, Tucana, Phoenix and Sculptor. The asterism consists of 7 main stars and there are 28 stars with Bayer/Flamsteed designations. Grus is visible to all observers at latitudes between +34° and ?34° and is best seen at culmination during the month of October.

Until the late 16th century, Grus was considered part of Piscis Austrinus – the “Southern Fish” – since most of its stars weren’t visible to northern latitudes. When exploration began below the equator many wondrous new creatures were discovered. One such bird was the fishing crane – Phoenicopterus – the flamingo. Perhaps this is how the constellation got is name, since Grus is also Dutch for “crane”!

First let’s take a binocular tour of Grus, starting with its brightest star, Alpha, the “a” symbol on our map. Alpha Gruis proper name is Alnair, the Arabic word for “bright one of the tail”. In this case, it was originally the tail of the fish. But besides being a bit “fishy”, Alnair is a hot, blue subgiant giant star about 101 light years away from Earth. Not only is it larger, hotter and brighter than our own Sol, but it a rather fast stellar rotation – making a complete rotation in under a day. Hop on to Beta Gruis, the “B” symbol on our map. Beta Gruis is a rare kind of star – a cooler class M giant star. It is very possible it is in an advanced state of evolution, losing mass and brightening with a dead carbon-oxygen core in preparation for sloughing its outer envelope – ready to become a Cepheid variable!

Now for visual and binocular double star, Delta 1 and Delta 2 Gruis – the “8” symbol in the center of the constellation. While this pair aren’t physically connect to one another, they do make a pleasing sight with their lovely yellow and red contrasting colors. For a true telescopic binary star, hop north to Upsilon. This disparate pair is separated by over a degree of arc and the difference between stellar magnitudes is a great experience.

For the telescope, tackle NGC 7213 (RA 22:09.3 Dec -47:10) about 16′ southeast of Alpha. This 10th magnitude Seyfert galaxy has definitely got some stories to tell. Not only is it a spiral galaxy, but one that has an incredible,giant H-alpha filament erupting from its nucleus. Another great challenge is NGC 7582, 7590 and 7599 (RA 023:19 Dec -42:3). Here is a small galaxy group consisting of three faint spirals in the same field, all tilted close to edge on. While at least an intermediate sized telescope is need to see them, a wide field eyepiece will place all three in the same field of view at around 100x magnification. Before we leave for the night, let’s try NGC 7410 (22:55.0 -39:40). This uniformly illuminated tilted spiral galaxy shows little sign of structure, despite its bright nature.

Sources: Wikipedia, SEDS
Chart courtesy of Your Sky.

Weekend SkyWatcher’s Forecast – November 7-9, 2008

Greetings, fellow StarGeezers! It’s Friiiii day… And another great weekend forecast. Does having all this Moon around get you down? It shouldn’t. Where else could you find another world that you could so intimately study detail with even the most modest of telescopes or binoculars? Instead of cursing Luna’s presence, get out your optics and enjoy! While we’re at it, we’ll take a look at some very interesting stars – both in the sky and from planet Earth. It’s time to head out into the dark… Cuz’ here’s what’s up!

Friday, November 7, 2008 – Today in 1996, the Mars Global Surveyor left on its journey. Just 30 years beforehand on this same day, Lunar Orbiter 2 was launched. Tonight let’s launch our way toward the Moon as we begin our observing evening with a look at a far northern crater – J. Herschel.

Residing on the mid-northern edge of Mare Frigoris, this huge, shallow old crater spans 156 kilometers and bear the scars of the years. Look for the deeper and younger crater Horrebow on the southwestern wall – for it has obliterated another, older wall crater.

Ready to aim for a bullseye? Then follow the “Archer” and head right for the bright, reddish star Aldebaran. Set your eyes, scopes or binoculars there and let’s look into the “eye” of the Bull.

Known to the Arabs as Al Dabaran, or “the Follower,” Alpha Tauri got its name because it appears to follow the Pleiades across the sky. In Latin it was called Stella Dominatrix, yet the Olde English knew it as Oculus Tauri, or very literally the “eye of Taurus.” No matter which source of ancient astronomical lore we explore, there are references to Aldebaran.

As the 13th brightest star in the sky, it almost appears from Earth to be a member of the V-shaped Hyades star cluster, but this association is merely coincidental, since it is about twice as close to us as the cluster is. In reality, Aldebaran is on the small end as far as K5 stars go, and like many other orange giants, it could possibly be a variable. Aldebaran is also known to have five close companions, but they are faint and very difficult to observe with backyard equipment. At a distance of approximately 68 light-years, Alpha is “only” about 40 times larger than our own Sun and approximately 125 times brighter. To try to grasp such a size, think of it as being about the same size as Earth’s orbit! Because of its position along the ecliptic, Aldebaran is one of the very few stars of first magnitude that can be occulted by the Moon.

Saturday, November 8, 2008 – Even if you only use binoculars tonight, you can’t miss the beautiful C-shape of Sinus Iridum as it comes into view on the lunar surface. As we have learned, the mountains ringing it are called the Juras, and the crater punctuating them is named Bianchini. Do you remember what the bright tips of the opening into the “Bay of Rainbows” are called? That’s right: Promontorium LaPlace to the northeast and Promontorium Heraclides to the southwest. Now take a good look at Heraclides… Just south of here is where Luna 17 landed, leaving the Lunokhod rover to explore!

Born on this day in 1656, the great Edmund Halley made his mark on history as he became best known for determining the orbital period of the comet which bears his name. English scientist Halley had multiple talents however, and in 1718 discovered that what were then referred to as “fixed stars,” actually displayed (proper) motion! If it were not for Halley, Sir Isaac Newton may never have published his now famous work on the laws of gravity and motion.

Now turn your eyes or binoculars just west of bright Aldebaran and have a look at the Hyades Star Cluster. As noted yesterday, Aldebaran appears to be part of this large, V-shaped group, but is not an actual member. The Hyades cluster is one of the nearest galactic clusters, and it is roughly 130 light-years away at its center. This moving group of stars is drifting slowly away toward Orion, and in another 50 million years will require a telescope to view!

Sunday, November 9, 2008 – Today is the birth date of Carl Sagan. Born in 1934, Sagan was an American planetologist, exobiologist, popularizer of science and astronomy, and novelist. During his lifetime, Sagan published more than 600 scientific papers and popular articles and was author, co-author, or editor of more than 20 books. His influential work and enthusiasm inspired us all. As Dr. Sagan once said, “Personally, I would be delighted if there were a life after death, especially if it permitted me to continue to learn about this world and others, if it gave me a chance to discover how history turns out.”

May his dreams live on..

If Carl were with us tonight, he would encourage amateurs at every level of astronomical ability! So let us honor his memory by beginning with an optical pairing of stars known as Zeta and Chi Ceti, a little more than a fistwidth northeast of bright Beta. Now have a look with binoculars or small scopes because you’ll find that each has its own optical companion!

Now drop south-southwest less than a fistwidth to have a look at something so unusual that you can’t help but be charmed – the UV Ceti System (RA 01 39 01 Dec -17 57 01).

What exactly is it? Also known as L 726-8, you are looking at two of the smallest and faintest stars known. This dwarf red binary system is the sixth nearest star to our solar system and resides right around nine light-years away. While you are going to need at least an intermediate-size scope to pick up these near 13th magnitude points of light, don’t stop observing right after you locate it. The fainter member of the two is what is known as a “Luyten’s Flare Star” (hence the “L” in its name). Although it doesn’t have a predictable timetable, this seemingly uninteresting star can jump two magnitudes in less than 60 seconds and drop back to “normal” within minutes – the cycle repeating possibly two or three times every 24 hours. A most incredible incident was recorded in 1952 when UV jumped from magnitude 12.3 to 6.8 in just 20 seconds!

No matter what you choose to look at tonight, as Dr. Sagan would say: “We are all star stuff.”

Have a great week and I’ll see you… Under the stars!

This week’s awesome photos are: Crater J. Herschel – Credit: Wes Higgins, Aldebaran – Credit: Palomar Observatory, courtesy of Caltech, Sinus Iridum – Credit: Wes Higgins, Edmund Halley (widely used public image), The Hyades Star Cluster – Credit: NASA, Carl Sagan (widely used public image), and Chi and the UV Ceti System – Credit: Palomar Observatory, courtesy of Caltech. Our many thanks to you!

The Cosmic Web – NGC 2070 by Joseph Brimacombe

The Cosmic Web - NGC 2070 by Joseph Brimacombe

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Just one glance at this incredible visage is enough to make you do a double take. This intricate net of nebular mists is known as 30 Doradus, or even more commonly as the “Tarantula”, but no space spider created this web. No, sir. What spun out these gossamer strands of HII silk is one of the largest and most active star forming regions known to our local galaxy group…

When Nicolas Louis de Lacaille first saw it in 1751 through his half-inch spyglass, he knew it was something different. He wrote down that it was nebular in nature, without stars and said; “It resembles the nucleus of a small comet.” Too bad he didn’t realize what he was really looking at, for Lacaille was a huge fan of all things science. What he couldn’t see with his primitive telescope is there really is a cluster of stars at the heart of this web… A very compact cluster stars known as R136a. And in its midst? Twelve stars… twelve very massive and luminous stars almost exclusively of spectral type O3. Even at a distance of 180,000 light years these stars light up this nebula so brightly that if it were as close to Earth as the Orion Nebula, it would cast shadows on the night.

So what else lay hidden in the 1000 light year expanse of the cosmic web? Look beyond what you can see in visible light and think like a spider… Try infra-red. With the eyes of the Spitzer Space Telescope aimed towards NGC 2070, scientists could penetrate the dust clouds throughout the Tarantula to reveal previously hidden sites of star formation. Within the luminescent nebula, holes began to appear. These voids are created by highly energetic winds spewing out from the massive stars in the central star cluster. Like the intricate designs woven by the spider, the structures at the edges of these voids are particularly interesting. Dense pillars of gas and dust, sculpted by the stellar radiation, will be the birthplace of future generations of stars!

But like the spider web… It’s a place of death, too.

In 1987 one of the closest supernova events ever to occur near Earth happened in the outskirts of the Tarantula Nebula. The light from the supernova reached Earth on February 23, 1987 and not.since 1604 had humankind been witness to such an event. Even though we were witnessing something that occurred 168,000 years in the past, those X-ray and radio emission were still just as bright as the day the highly energetic electrons and particles spewed into the interstellar medium upon the explosive death of the progenitor star. Oh, there is skeletons in the web, too. Older and weaker supernovae remnants are scattered about, their signatures as faint as the imprint of a fallen leaf that has long blown away. This “Cosmic Web” is home to many supergiant stars. At any moment, a snapshot of any dense region of supergiant stars will show a mixture of newborn stars and supernovae, the signature of stars who those that have lived fast and died young.

Many thanks to AORAIA member, Joe Brimacombe for allowing me to swipe his wonderful image and tell a story.

Weekend SkyWatcher’s Forecast – October 31 – November 2, 2008

Happy Halloween! Are you ready for the Spook’s Tour? Tonight treat your little ghouls and goblins, party guests and yourself to a real sweet treat through your telescope or binoculars as we take a look at some of the season’s craziest (and scariest) outer space objects. It’s a time honored custom that’s sure to please even the most starched shirt out there… So loosen up your tie and let’s have some fun! Need more to keep you busy? Sure! We’ll also take a look at the weekend’s lunar features, the magnificent “Double Cluster” and a salute to Harlow Shapely! Now, let’s haunt the weekend together…

Friday, October 31, 2008 – Happy Halloween! Many cultures around the world celebrate this day with a custom known as “Trick or Treat.” Tonight instead of tricking your little ghouls and goblins, why not treat them (or your party guests) to a sweet view through your telescope or binoculars? Let’s take a look at some of the “spookiest” objects in the night sky…

Begin in the constellation of Perseus with a single star. Its formal name is Beta Persei (RA 03 08 10 Dec +40 57 20) and it is the most famous of all eclipsing variable stars. Tonight, let’s identify Algol and learn all about the “Demon Star.”

Ancient history has given this star many names. Associated with the mythological figure Perseus, Beta was considered to be the head of Medusa the Gorgon, and was known to the Hebrews as Rosh ha Satan or “Satan’s Head.” Seventeenth century maps labeled Beta as Caput Larvae, or the “Specter’s Head,” but it is from the Arabic culture that the star was formally named. They knew it as Al Ra’s al Ghul, or the “Demon’s Head,” and we now know it as Algol. Because these medieval astronomers and astrologers associated Algol with danger and misfortune, we are led to believe that Beta’s strange visual variable properties had been noted throughout history. Italian astronomer Geminiano Montanari was the first to record that Algol occasionally “faded,” and its regular timing was cataloged in 1782 by John Goodricke, who surmised that it was being partially eclipsed by a dark companion orbiting it. Thus was born the theory of the eclipsing binary, which was proved spectroscopically for Algol in 1889 by H. C. Vogel.

93 light-years away, Algol is the nearest eclipsing binary, and is treasured by the amateur astronomer because it requires no special equipment to easily follow its stages. Normally Beta Persei holds a magnitude of 2.1, but approximately every three days it dims to magnitude 3.4 and gradually brightens again. The entire eclipse only lasts about 10 hours! Although Algol is known to have two additional spectroscopic companions, the true beauty of watching this variable star is not telescopic – but visual. The constellation of Perseus is well placed this month for most observers, and appears like a glittering chain of stars that lie between Cassiopeia and Andromeda. Take a look at Gamma Andromedae (Almach), east of Algol. Almach’s visual brightness is about the same as Algol’s at maximum.

Now we need a jack-o-lantern…

Asteroid Vesta is considered to be a minor planet since its approximate diameter is 525 km (326 miles), making it slightly smaller in size than the state of Arizona. Vesta was discovered on March 29, 1807 by Heinrich Olbers and it was the fourth such “minor planet” to be identified. Olbers’ discovery was fairly easy because Vesta is the only asteroid bright enough at times to be seen unaided from Earth. Why? Orbiting the Sun every 3.6 years and rotating on its axis in 5.24 hours, Vesta has an albedo (or surface reflectivity) of 42%. Although it is about 350 million kilometers away, pumpkin-shaped Vesta is the brightest asteroid in our solar system because it has a unique geological surface. Spectroscopic studies show it to be basaltic, which means lava once flowed on the surface. (Very interesting, since most asteroids were once thought to just be rocky fragments left-over from our forming solar system!)

Studies by the Hubble telescope have confirmed this, as well as shown a large meteor impact crater which exposed Vesta’s olivine mantle. Debris from Vesta’s collision then set sail away from the parent asteroid. Some of the debris remained within the asteroid belt near Vesta, and became asteroids themselves with the same spectral pyroxene signature. But some of the debris escaped the asteroid belt through the “Kirkwood Gap” created by Jupiter’s gravitational pull. This allowed these small fragments to be kicked into orbits that would eventually bring them “down to Earth.” Did one make it? Of course! In 1960 a piece of Vesta fell to Earth and was recovered in Australia. Thanks to Vesta’s unique properties, the meteorite was definitely identified as coming from our third largest asteroid. Now, that we’ve learned about Vesta, let’s talk about what we can see from our own backyards. As you can discern from the image, even the Hubble Space Telescope doesn’t give incredible views of this bright asteroid. What we will be able to see in our telescopes and binoculars will closely resemble a roughly magnitude 7 “star.” Tonight you can find Vesta near Alpha Ceti. Vesta will be at opposition in just three days, and is now in retrograde, so you will be able to watch it slowly move away from Alpha Ceti for the rest of the year.

Of course, the approximate coordinates given above are only accurate for a short time, so I strongly encourage you to use a good planetarium program to print accurate locator charts, or visit an online resource such as the IAU Minor Planet Center for more details. When you locate the proper stars and the asteroid’s probable location, mark physically on the map Vesta’s position. Keeping the same map, return to the area a night or two later and see how Vesta has moved since your original mark. Since Vesta will stay located in the same area for awhile, your observations need not be on consecutive nights, but once you learn how to observe an asteroid and watch it move – you’ll be back for more!

One of the scariest movies in recent times was the “Ring”… Let’s find one! Tonight’s dark-sky object is a difficult one for northern observers and is truly a challenge. Around a handspan south of Zeta Aquarii and just a bit west of finderscope star Upsilon (RA 22 51 48 Dec 20 36 31) is a remarkably large area of nebulosity that is very well suited to large binoculars, rich field telescopes and wide field eyepieces. Are you ready to walk into the “Helix?”

Known as NGC 7293, this faint planetary nebula’s “ring” structure is around half the size of the full Moon. While its total magnitude (6.5) and large size should indicate it would be an easy find, the Helix is anything but easy because of its low surface brightness. Binoculars will show it as a large, round, hazy spot, while small telescopes with good seeing conditions will have a chance to outshine larger ones by using lower power eyepieces to pick up the braided ring structure. As one of the very closest of planetary nebulae, NGC 7393 is very similar in structure to the more famous Ring, M57. It is a spherical shell of gas lighted by an extremely hot, tiny central star that’s only around 2% of our own Sun’s diameter – yet exceeds Sol in surface temperature by over 100,000 Kelvin. Can you resolve it? Best of luck!

Just two days before Halloween in 1749, the French astronomer Le Gentil was at the eyepiece of an 18′ focal length telescope. His object of choice was the Andromeda Galaxy, which he believed to be a nebula. Little did he know at the time that his descriptive notes also included M32, a satellite galaxy of M31. It was the first small galaxy discovered, and it would be another 175 years before these were recognized as such by Edwin Hubble. Now let’s head about a degree west of Nu Andromedae, this “ghost” set against the starry night was known as far back as 905 AD, and was referred to as the “Little Cloud.” Located about 2.2 million light-years from our solar system, this expansive member of our Local Galaxy Group has delighted observers of all ages throughout the years. No matter if you view with just your eyes, a pair of binoculars or a large telescope, M31 still remains one of the most spectacular galaxies in the night. “Boo” tiful…

What Halloween celebration would be complete without a black cat? Let’s cruise Draco (the Dragon) in search of the “Cat’s Eye”…

Located about halfway between Delta and Zeta Draconis is one of the brightest planetary nebulae in the night – 8.8 magnitude NGC 6543. Around three thousand light-years away, it was one of the first planetaries to be studied spectroscopically, and the resulting emission lines proved the phenomenon was actually a shell of gas emitted from a dying star. Our own Sun awaits a similar fate. While a small telescope will never reveal NGC 6543 as gloriously as a Hubble image, you can expect (even in a small telescope or binoculars) to make out a small, blue-green, glowing object. But a large aperture telescope and good sky conditions are needed to reveal some of the braided structure seen within. No matter how you view it, the Cat’s Eye belongs on the list of spooky objects!

So far we’ve collected a demon, a pumpkin, a galactic ghost, and the eye of the cat… And what Halloween would be complete without a witch! Easily found from a modestly dark site with the unaided eye, the Pleiades can be spotted well above the northeastern horizon within a couple of hours of nightfall. To average skies, many of the seven bright components will resolve easily without the use of optical aid, but to telescopes and binoculars?… M45 is stunning!

First let’s explore a bit of history. The recognition of the Pleiades dates back to antiquity, and its stars are known by many names in many cultures. The Greeks and Romans referred to them as the “Starry Seven,” the “Net of Stars,” “The Seven Virgins,” “The Daughters of Pleione,” and even “The Children of Atlas.” The Egyptians referred to them as “The Stars of Athyr;” the Germans as “Siebengestiren” (the Seven Stars); the Russians as “Baba” after Baba Yaga, the witch who flew through the skies on her fiery broom. The Japanese call them “Subaru;” Norsemen saw them as packs of dogs; and the Tongans as “Matarii” (the Little Eyes). American Indians viewed the Pleiades as seven maidens placed high upon a tower to protect them from the claws of giant bears, and even Tolkien immortalized the star group in The Hobbit as “Remmirath.” The Pleiades were even mentioned in the Bible! So, you see, no matter where we look in our “starry” history, this cluster of seven bright stars has been part of it. But, let’s have some Halloween fun!

The date of the Pleiades culmination (its highest point in the sky) has been celebrated throughout its rich history, being marked with various festivals and ancient rites – but there is one particular rite that really fits this occasion! What could be more spooky on this date than to imagine a group of Druids celebrating the Pleiades’ midnight “high” with Black Sabbath? This night of “unholy revelry” is still observed in the modern world as “All Hallow’s Eve,” more commonly called Halloween. Although the actual date of the Pleiades midnight culmination is now on November 21 instead of October 31, why break with tradition? Thanks to its nebulous regions, M45 looks wonderfully like a “ghost” haunting the starry skies.

Treat yourself and your loved ones to the “scariest” object in the night. Binoculars give an incredible view of the entire region, revealing far more stars than are visible with the naked eye. Small telescopes at lowest power will enjoy M45’s rich, icy-blue stars and fog-like nebulosity. Larger telescopes and higher power reveal many pairs of double stars buried within its silver folds. No matter what you choose, the Pleiades definitely rock!

Saturday, November 1, 2008 – On this day in 1977, Charles Kowal made a wild discovery – Chiron. This was the first sighting of one of the multitude of tiny, icy bodies inhabiting the outer reaches of our solar system. Collectively known as Centaurs, they reside in unstable orbits between Jupiter and Neptune and are almost certainly “refugees” from the Kuiper Belt.

This evening have a look at the lunar surface and the southeast shoreline of Mare Crisium for Agarum Promontorium. To a small telescope it will look like a bright peninsula extending northward across the dark plain of Crisium’s interior, eventually disappearing beneath the ancient lava flow. Small crater Fahrenheit can be spotted at high power to the west of Agarum, and it is just southeast of there that Luna 24 landed. If you continue south of Agarum along the shoreline of Crisium you will encounter 15 kilometer high Mons Usov. To its west is a gentle rille known as Dorsum Termier – where the remains of the Luna 15 mission lie. Can you spot 23 kilometer wide Shapely further south?

Tonight let’s use our eyes, binoculars, or even a telescope at lowest power to have a look at two objects cataloged by Sir William Herschel on this night. You may know them as the “Double Cluster”. Properly designated as NGC 869 and NGC 884, this pair has definitely got to go into history as “How come Messier missed them?” Probably already known in pre-historic times, and first cataloged by Hipparchus (ah! that’s why!), they are easily seen by the eye as a hazy patch in the Milky Way between Cassiopeia and Andromeda. Located a little more than 7000 light-years away, and a few hundred light-years apart, they are both very young as clusters go – but they differ radically from each other in age: NGC 884 is about 5.6 million years old, while NGC 889 is only 3.2 million. Both clusters are listed on many “Best Objects” lists, so be sure to congratulate yourself for noting them as Caldwell 14!

Sunday, November 2, 2008 – Today celebrates the birth of an astronomy legend – Harlow Shapely. Born in 1885, the American-born Shapley paved the way in determining distances to stars, clusters, and the center of our Milky Way galaxy. Among his many achievements, Shapely was also the Harvard College Observatory director for many years. Today in 1917 also represents the night first light was seen through the Mt. Wilson 100″ telescope.

Of course, Dr. Shapley spent his fair share of time on the Hooker telescope as well. A particular point of his studies were globular clusters: their distances, and the relationship they have to the halo structure of our galaxy. Tonight let’s look at a very unusual little globular located about a fistwidth south-southeast of Beta Ceti, and just a couple of degrees north-northwest of Alpha Sculptoris (RA 00 52 47 Dec -26 34 43). Its name is NGC 288…

Discovered by William Herschel on October 27, 1785, and cataloged by him as H VI.20, this class X globular cluster blew apart scientific thinking in the late 1980s when a study of perimeter globulars showed it to be older than its X-class peers by three billion years – thanks to the color magnitude diagrams of Hertzsprung and Russell. NGC 288 is currently thought to be about 11 billion years old. By identifying both its blue and red branches, it was shown that many of NGC 288’s stars are being stripped away by tidal forces and contributing to the formation of the Milky Way’s halo structure. In 1997, three additional variable stars were discovered in this cluster. At magnitude 8, this small globular is easy for southern observers, but faint for northern ones. If you are using binoculars, be sure to look for the equally bright spiral galaxy NGC 253 to the globular’s north.

This week’s awesome images are: Beta Persei: Algol – Credit: Palomar Observatory, courtesy of Caltech, Asteroid Vesta – Credit: NASA, NGC 7293: The Helix Nebula – Credit: R. Jay GaBany, The Andromeda Galaxy – Bill Schoening, Vanessa Harvey/REU program/NOAO/AURA/NSF, NGC 6543: The Cat’s Eye – Credit: Hubble Heritage Team/NASA, M45: The Pleiades – Credit: John Chumack, The “Double Cluster” – Credit: N.A.Sharp/NOAO/AURA/NSF, Lunar image by Greg Konkel, annotated by Tammy Plotner, Harlow Shapely (widely used public image) and NGC 288 – Credit: Palomar Observatory, courtesy of Caltech. Our many, many thanks for the fine illustrations!