The Skies OfAs stars go, our sun is no more or less important than the great majority of stars we see in the night sky. Except for the fact that it sustains all life in our solar system, it is only one of the hundreds of billions of stars that make up our island universe. It travels in what is known as the Orion arm of the galaxy. A middle aged, average-sized star, it just barely adds its own two cents to the whole. From the distance of the Andromeda galaxy, some 2.2 million light years away, an astronomer there would be hard pressed, without any optical aide to even detect it at all. What this astronomer would see in a telescope, however, is the great conglomeration of stars that we call the Milky way. Similar to what we see as we look at Andromeda, both it and the Milky way are fairly common spiraling disks of stars, gas and dust. They're not at all unlike the galaxies we see throughout the Universe. We are certainly not alone.
An easy way to start your hunt for the Andromeda galaxy, known since ancient times as the Little Cloud, is via the giant diamond-shaped and oriented Square of Pegasus well above the horizon and the Pisces constellation. At this time of year, using the square's east, or left most point as a jumping off place, the stars sweeping out away from the horse's main body represent the Princess Andromeda in a reclined position. Within this area resides one of the most famous of all DSOs. Thirteen thousand quadrillion miles, give or take a few billion, or 2.2 million light years away is how far Andromeda is from us. It also happens to be the most distant object in the entire sky that can be detected with eyes alone. No other extragalactic phenomena can be seen this way.
There are, of course, dozens, if not hundreds of distant, naked eye objects within our own galaxy, including all the stars we can see. Every one of them, however, resides within the confines of our galaxy, the Milky-Way. None of them compare in size and distance to the enormous, and often photographed M 31. It's also one of those dark sky sights that lies at the cusp of visibility. It can be glimpsed with eyes alone, though you may need to use averted vision. Add binoculars or a small telescope to the mix, and voila, a truly heavenly sight to behold. And like our galaxy's Small and Large Magellanic Clouds, Andromeda too, is home to orbiting satellite galaxies.
In binoculars, the cloud is easily discernable as an oval patch, even brightening at the center. In small to medium telescopes its companion ellipticals, M-32 and M110, small oval-shaped satellite galaxies, are visible as well. Nearest to M-31 and easy to spot in a mid to large-size telescope, M-32 is the closer of the two satellites. In the opposite direction, M-110 lies a little further out over on the other side of the Little Cloud. It was the last of the posthumously added objects to Charles Messier's famous list of nebulae.
The Little Cloud is, of course, the main attraction. Much has been written and learned about this island universe, believed by many to be the mirror image of our own galaxy. Interestingly enough, considering the distance, what we see today, fantastically, is how it looked over two millions years ago. We won't know for some time if there have been any dramatic changes to our largest neighbor. If, let's say, a major supernova were to happen today, we'd have to wait two million plus years to see it unfold. Put that in your Lawnchair's well-worn cup holder and ponder to taste.
These two major galaxies, M-31 and the Milky-Way, and their satellites, as well as the few dozen or so relatively nearby galaxies, are members of what is known as the Local Group. This batch of galaxies populating our neighborhood of the Universe, in turn, is part of the larger consortium of galaxies known as the Virgo-Coma cluster.
M-31 was wondered about as far back as 905 AD and, as I mentioned earlier, was known as "The Little Cloud". It's been found on early star maps, well before telescopes were invented. In the sixteen hundreds, Simon Marius was credited for being the first to telescopically peruse the elongated dim patch of light. For sometime it was theorized that M 31 was a forming solar system and it wasn't until spectroscopic analysis confirmed the error when it was finally proven that, among other evidence, this object's light originated from numerous individual stars.
Edwin Hubble was responsible for the first scientific determination that this Little Cloud nebula was not part of our galaxy, but in reality, was an entire galaxy itself. Up until that point, less than a hundred years ago, we had not yet realized that our galaxy was not the whole Universe. While studying the Andromeda galaxy in the nineteen twenties, Hubble, using spectro-analysis, which was a relatively new process at the time, examined what turned out to be stars there that were identical to the Cepheid Variable stars here in the Milky-Way. Knowing the characteristics of the Cepheids, it allowed him to more accurately calculate the distance to those stars. Spectrographic analysis was found to be a reliable way to measure the distance to these certain types of stars. The Cepheids in Andromeda display identical spectra and variability as those here. That specific spectrum signature is what makes it possible for spectroscopy to determine their distances. It is also used to determine their speed and direction of travel. (See section on Red & Blue Shifting)
Andromeda is the closest large spiral in the local group. The only closer systems to the Milky-way are the Large and Small Magellanic Clouds. Unfortunately for northern hemisphere Lawnchairs, they are viewable only from extreme southern hemisphere locations. The next closest is a small dwarf galaxy known as "Snickers", and is only detectable as a radio source in the direction of the red giant Betelgeuse in Orion.
Another interesting aspect of M 31 is that astronomers have located, studied and photographed individual star clusters within the galaxy's spiral arms. The similarities between Andromeda and our galaxy are profound, confirming that the phenomena is common throughout the Universe. Perhaps beyond the range of many amateur instruments, in the lens of a really large backyard telescope, under excellent seeing conditions, a few of these outlying clusters in Andromeda may glimpsed as brightening knots in its outer regions.
Lastly, a quite peculiar object resides within Andromeda's borders. NGC 7662, a planetary nebula, not dissimilar to the Ring Nebula in Lyra, exhibits an odd bluish green color. Attainable in both small and large instruments, in smaller scopes it looks like a fuzzy blue star, often referred to as the Blue Snowball. You may get a hint of its structure in larger telescopes. It's a bit like M-57, the Ring Nebula in Lyra.
PegasusThe diamond oriented square of Pegasus is basically the winged horse's body, with the neck and legs extending away from the square. Pegasus is hardly an uninteresting section of sky. Home to almost 2 dozen galaxies, albeit galaxies that may beyond the reach of most amateur instruments, Pegasus does contain M 15, a wonderful globular cluster that is detectable in binoculars. You will need a substantially larger instrument, however, to pick up any detail, or to resolve it into its countless stars. The cluster shines with a brilliancy of more than 200,000 times our sun. It is also one of the brightest clusters in the heavens, perhaps only second to the great cluster in Hercules. It's dim to us only because of its great distance. Find it a few degrees from the star Enif.
Also at home within Pegasus is a small galaxy cluster called Stephan's Quintet. Just below, by about a half of a degree, of NGC 7331, one of the brighter NGCs in Pegasus, this group of 5 galaxies is just beyond small instrument capabilities, though, those of you with larger 10 to 14 inch instruments may attempt a "look-see". The brightest member of this group is at a whopping 13.7 magnitudes, its brethren between 14th and 15th magnitudes. Don't expect to see amazing detail, although, you may be able to glimpse this parade of DSOs, if only as dim, funny shaped smudges of light.
The previously mentioned NGC 7331 is also a target worth hunting for. It is a classic example of a spiral galaxy, often compared to our own Milky-way and how it would look from this distance and angle. Even in large instruments, at best, you'll see a smallish oval patch. While in long exposure photographs it reveals a beautiful spiraling pattern of dust lanes and bright areas thick with stars. Definitely a Lawnchair Trophy Chest item, this is one of those that you'll come back to see anytime it's available.
Of the remaining NGCs in Pegasus, all are better left to the professionals and deep sky photo buffs. The small cluster NGC 7772 lies about a third of the way just above the line between Algenib and Markab. Just a few stars strong, its brightest member is only 11th magnitude, its dimmest, around 14.
Other than that, Pegasus is a very easy constellation to recognize and use as a starting point for locating its neighbors. By mid-summer, it can be found rising in the East just after dark and will remain in the skies until late autumn and early winter where you can see it touching the western horizon just after sunset.
PiscesFacing south during mid-autumn, you'll easily be able to see the great square of Pegasus high overhead. Use it as a starting point. It is truly a key to each of the constellations of this section. Below it notice how the Piscean V sort of fits like a puzzle piece into its southeastern corner. On the other side of the V, notice the bright star Hamal over in Aries, which itself basically looks like a farmer's sickle. A bit further up the left side of the V is where you can see the small Triangulum.
The realm of "the Fish" rising off the Eastern horizon after dark at this time of year is also another easy constellation to recognize and learn. Seen as a giant letter V whose right arm ends in a small circlet of stars, Pisces is supposed to represent two fish swimming the heavens. We start our tour with Alpha Piscium at the bottom of the V or as the Arabs called it, "The Cord". Its actual name, Al Rischa or Okda refers to the flaxen cord that binds the two fish together. A double star just made for amateur instruments, Alpha Piscium has been the subject of controversy for ages. The peculiar reports of this pair's color have gone from greenish white and blue to pale or brown yellow. Still one 20th century astronomer offered just "a pair of weird colored stars", and that's apparently all that was dared to say in the late 1920s. Suspected to be a variable star, the primary of the group has been studied at length and still no precise determination has been committed to the Piscean constituent. Find and take a close look at this star pair and see what you can determine for color.
Another interesting star in Pisces is called Van Maanen's Star which is located a few degrees south of Delta Piscium. This is one of the very few "white dwarf" stars that can be seen with amateur grade instruments. Among one of the smallest stars known, it is also possibly the closest white dwarf star to our solar system, save for the faint companions of Sirius and Procyon. Almost as small as the planet earth, it contains the mass of our sun which makes this an extraordinary twinkle. Presumably this is perhaps a member of the group of stars considered the oldest in the galaxy. At a mere 13.8 light years away, this star no longer produces any real energy and can be seen only as a remaining ember.
Along the left side of the Piscean V, about midway up is the star known as Eta Piscium. It's neighbor to the left is M 74, a face on spiral galaxy that is reputed to be one of the hardest of the Messier objects to view. But don't let that dissuade you from at least attempting to spot this dim galaxy. A perfect example of what is known as a face on nebulae, it was first found in 1780 by Pierre Mechain, a month before Charles Messier added it to his catalog. Again, a wide angle, low power eyepiece will be best suited for observing this target as it is quite dim. Interestingly though, this object lies between 28 and 42 million light years away from us. No wonder it's a little difficult to see.
Another especially beautiful face on galaxy in Pisces is NGC 488. In photographs, evident is the almost perfectly circular nebula with thin though well-defined spiral lanes of stars and dust. Also within the borders of Zodiacal fish lie a few peculiar galaxies, one of which seems to be going through some traumatic changes and upheavals. NGC 520, as seen in photographs with the giant 200 inch telescope at the Palomar observatory, may perhaps be the result of a pair of colliding irregular galaxies. And finally, NGC 128 has a peculiar box shape to it, making it quite unique in all the heavens. Both of these are only available on deep sky photographs but still quite interesting none the less.
Back to harping on the authors who named the constellations, here in this small area of sky we've got a pair fish supporting both the queen and her flying horse. Whatever it was they were drinking or smoking in those days, I'm pretty sure they'd be outlawed today. That or you'd need a "special" prescription. I can only attribute it to campfire intoxication, but this truly is a wonderful time of year for the Lawnchair to get a last look at the soon to be disappearing summer constellations as they sink down below the western treetops and take all those great jewels out of view. However, winter's best sights are now making their way up above the eastern horizon as the night wears on into early morning. It still hasn't gotten bone-chilling cold out and for that reason alone, makes this a great opportunity to see those special treats without trudging through feet of snow and ice. Try it, you'll like it, as the commercial use to recommend. The Lawnchair will thank you in the morning. Now where have I heard that before?
The Lawnchair Astronomer
Gerry Descoteaux is the author of “The Lawnchair Astronomer,” a Dell Trades paperback. He has been writing about astronomy for more than 25 years. He also played an integral role in the development of America Online’s pioneering distance education program known as AOL’s Online Campus and served as Professor of Astronomy there for 10 years. He can be reached at TheStarMan@thelawnchairastronomer.com.
Notes From the Lawnchair