Joyous JanuaryIn the area of sky centered just about on what we today call the North Star, is where the Earth's revolution produces a nightly and annual rotation of the sky around this central point. This point is where you will find the star Polaris, which is also the end star of the handle of what is known as the Little Dipper or Ursa Minor. It is also cataloged as the Alpha star of the formally named constellation. Stars of a constellation, especially those without formal or famous names are catalogued by letters of the Greek and/or Latin alphabets. This entire region of sky and the constellations therein never set completely below the horizon. Rather, they rotate around this central point over the course of an evening and throughout the year as the Earth travels around the sun. These are known as the Circumpolar Constellations. The attending locator map is obviously accurate only during one specific time of year. However, the entire area rotates an entire 360 degrees over the course of a year. A camera centered on this point with its shutter left open for several hours will produce spectacular star trail photos like that seen on the accompanying graphic.
Following are descriptions of the individual constellations in this area of the sky. As you will no doubt notice, in this area of circumpolar constellations, there are very few Messier objects, except for those few within the borders of Ursa Major. The reason is unclear as there are some bright NGC targets throughout the area. Perhaps Messier didn't feel he'd find any comets here and therefore, didn't include some of these obvious candidates to his list. Nevertheless, I've tried where possible to include some of the brighter NGC objects on the maps. However, the Messier targets are the best suited to amateur grade instruments. Against today's standards, Messier located these objects with a fairly crude three-inch instrument. A good pair of today’s technologically advanced binoculars will detect most of the objects on Messier's list. Today’s three to six inch amateur telescopes will, under optimum seeing conditions, be better able to "see" all of the objects in his catalog in more detail than he was ever able to.
The Big Dipper - Ursa Major
Beginning by facing the north, northwest, the easiest of all constellations to recognize is Ursa Major, or the Big Dipper. It can always be seen above the horizon regardless of its orientation. Check on it every now and then over the course of your late night adventures and note how it slings along the horizon, like as if a celestial chef was tossing its ingredients. Above it, directly due North, you should be able to make out the stars of the Little Dipper, as it seems to be pouring the contents of its smaller pot down into that of the large dipper. Also note that what is a singular phenomenon of the Northern Celestial Sphere, is that the star on which the whole system rotates, Polaris, better known as The North Star, doesn’t move over the course of the evening. All the other stars do.
Galactic Gifts from the Lawnchair Magi
From our vantage point, we are privy to hundreds of thousands of extra galactic nebulae, (galaxies) some similar to our own and others not so much. The great majority of galaxies are spiral shaped and resemble our Milky way. Though many are viewed from different perspectives. We see some of them from an edge on perspective, while some of the most awesome views are those inclined face on from our vantage point. Like the clusters of stars we see in our own galactic neighborhood, galaxies congregate in similar groups, of which our own is itself a member. Belonging to what we call the local group, ours is one of the main members, along with Andromeda, sharing this special association with about 20 others. This small group additionally belongs to the very large grouping known as the Coma Virgo Cluster. We can actually see some of the brighter members of this super grouping, of which we belong, along the borders between the Coma Berenices and Virgo constellations, following in the tail swings of Leo. They’re very dim but can be glimpsed in the largest backyard light buckets. (See Hubble Image)
From such backyard telescopes, members of this extremely dense population of galaxies can be peaked at under very dark, clear and moonless skies. In this group, besides the edge on and face on spirals, exist several irregular galaxies. Some are cigar shaped, while others seemingly have no specific shape at all, but rather, are seemingly just massive conglomerations of stars.
For viewers in the Southern Hemisphere, the familiar Small and Large Magellanic clouds are representative of this latter type. Interestingly enough is that over the course of the next few millions of years, these satellite galaxies will slowly but deliberately be absorbed by the Milky Way.
Ursa Major encompasses its own realm of galaxies. The Big Dipper contains a wonderful range of extra galactic targets, though, you will need access to a decent telescope to see them in person. Beginning with the "handle" of the Big Dipper, just below its end star, you'll see a wispy splash of light known as the Whirlpool Nebula, or M 51 as it is also known. Your best bet is to use a wide angle, low power eyepiece to first detect this very dim, yet expansive galaxy. However, as the Dipper occasionally stands on its "handle"which ends up just above the treetops, seeing through the atmospheric turbulence near the horizon may make viewing M 51 a bit of a challenge at those times of the year.
Of note, however, M 51, like the Milky Way and the Magellanic Clouds, has its own galactic satellite which seems to be in the process of being devoured by its much larger neighbor. To see it, let your eyes become very dark adapted first, then scan this area of sky just below the tail star of the handle. At first you may see what appears to be two bright spots, though as you use a technique known as averted vision, you just may be able to glimpse a bit more detail. The two bright spots you'll see are the two nuclei of each of these galaxies. In the long exposure photographs of M 51, the spiral structure and in falling material from its neighbor become dramatically apparent. Under optimal dark sky conditions away from city lights, though not as dramatic as seen in the photos, seeing M 51 in person is a long standing Lawnchair Trophy Chest Item at twenty-three million light years away.
Toward the other end of Ursa Major, up by the bucket's end stars, resides another pair of galaxies known respectively as M 81 and M 82. To find these, draw an imaginary line beginning from the bottom left star of the dipper's bucket, up through the top right star and out into space approximately an equal distance. M 81 is the face on spiral which is slightly tilted back away from us. Its partner is inclined more in the edge on perspective. Each of these can be seen in amateur grade instruments, though, the larger the better. They are fairly dim, but can both be seen in the same wide angle lens view.
Another easy target to find is M 109, just to the left and above the bottom right star of the dipper's bucket. This is another face on oriented galaxy and is further distinguished as a barred spiral. It can also be viewed with a large backyard telescope and, given the right sky conditions, will provide you with a glimpse of the barring that gives it its classification. Finally, another pair of galaxies, M 107 and M 108, are located a slight distance to the left of the bottom right star of the dipper's bucket. M 107 is also known as the Owl Nebula, sporting two owl eye like dark regions imbedded in the glow of its countless stars. The other, M 108 is another classic example of a face on spiral galaxy.
Sort of a house-shaped constellation, Cepheus is home, to among other things, Delta Cephei, which lies near Zeta Cephei, the bottom left star of the house (in an upright orientation from January to June). Perhaps the most famous of all variable stars, Delta Cephei was the first to be recognized as a star that changes its brightness, not because of a dimmer star passing in front of it, but by its own regular variations in brightness. It is like it has its own self-controlled dimmer switch. You could set a clock to this puppy! Why stars like the Cepheid Variables change on their own isn't completely understood. It may have to do with a common evolutionary stage of a star's life. Though, it will take more study to rule out several other theories. Some of which involve violent stellar weather patterns and even star quakes!
You can see these variations yourself over the course of as little as a few hours or days in some cases, while others can vary over a period of more than a month and a half. Amazingly, astronomers today can predict to within seconds, the exact time of maximums or minimums for Cepheid Variables. They are that constant. In the case of Delta Cephei, the period from minimum to maximum and back again lasts approximately five days, or evenings, in this case. You can watch this star change by gauging its brightness and comparing it each night to the nearby stars. It approaches maximum brightness in about a day and a half and takes nearly four days to return to its minimum. Because of their regular variations, astronomers have found that Cepheid Variables are excellent measuring sticks for determining the distances to distant galaxies which contain similar stars. Since this was first learned, hundreds more have been classified as Cepheid Variables. Typically, they are large white or yellow stars. Edwin Hubble, in the early part of the 20th century, found these very same stars in the Andromeda Cloud. At the time, it was considered a cloudy nebula. The Cepheid confirmation, however, served to confirm that Andromeda was indeed an external galaxy and not part of the Milky way. Today we know that the Milky way and Andromeda are the two major components of what is the Local Group of galaxies.
In Cepheus you can also easily locate its Alpha Star, Alderamin. It is the bottom right star of the house. Its claim to fame, other than being a bright and exceptionally rapidly rotating star, is that it resides in the path of Earth's precessional axis. Which means that like Thuban, Vega and Polaris, it has in the past and will again, in about 5,500 years from now, become the pole star.
As far as deep sky targets in Cepheus, there are but a scant few. The star cluster NGC 188 is perhaps the most famous of the bunch. It resides about 4 degrees away from Polaris. You'll need a decent size scope to get a peek at it though. An 8 inch telescope may deliver a fuzzy glimpse, while it may resolve into a few of its constituent members in a 12 inch instrument or greater. Its fame is derived from its incredibly old age. Containing perhaps the oldest stars in the entire galaxy, though still not completely agreed upon, NGC 188 is apparently nearly as old as the current estimates of the entire universe, somewhere between eight and thirteen billion years. It does sound like a paradox and a final determination has yet to be made.
Stars are categorized on a variety of criteria such as distance, color, luminosity, size, density and age. You may have heard the terms Population 1 and Population 2 in regard to specific types of stars. Population 1 stars, though this sounds back-ass-wards, (Lawnchair technical term) refers to second generation stars, those which formed from the debris left behind from exploding Population 2 stars. Population 2 stars are those that began their lives near the very beginning of the universe, sometime shortly after what we call the big bang occurred. In the NGC 188 cluster are the exceptionally old or what are called Population 2 type stars, well into their old-age phases. Theories abound with regard to their histories and reasons for longevity. Why haven’t they already met their respective demises? Wheaties or Cheerios every day? Red wine, fish and Cuban cigars?
Within the borders of Cepheus there are few other deep sky targets. Within the house borders of
Cepheus is NGC 7129, a diffuse nebula that might be impossible for amateur instruments, though under ideal dark sky conditions, in a larger scope, it may be attainable.
Near the border of the Cygnus constellation, with a larger instrument and a wide field lens, you can try to spot the spiral galaxy NGC 6946 and its close neighbor, a local galactic cluster called NGC 6939. This galaxy is a spiral, slightly tilted in appearance and, the cluster is, in my opinion, the more dramatic of the two. The galaxy will at best look dim and featureless in amateur instruments. While with some magnification, the open cluster will show off its jewel like properties. Combining both small and bright larger stars, this one is a sure bet to be added to your Lawnchair Trophy Chests if you can indeed spot it.
There are several other deep sky objects listed in any of the general catalogs. Burnham's lists about 2 dozen in all. Most of them, however, are too dim to be viewed directly. These are those that are best left to long exposure photographic observations.
Draco, the Dragon, is a lengthy collection of stars which begins with a small box shaped head followed by a slithering snake like body of stars that rise above and circle back around the Little Dipper, Polaris and the Big Dipper. The claim to fame for Draco is its Alpha star. Thuban, which at one time was the North Star, is the Arabic name for Dragon and the star lies about half way between the bucket of the Little Dipper and the double star, Mizar, in the Big Dipper's handle.
Incidentally, it was around 4800 years ago that Thuban was the North Star and it coincided with the Egyptian pyramid building era, more specifically, with the construction of the Khufu pyramid. It was built almost 500 years before the seeming alignment with Thuban and a passageway within the great pyramid. As Thuban was the North Star at that time, some archeologist believe that the two are connected somehow. The oddity results from how Egyptians of that era would have known where Thuban would be 500 years in the future. This was a feat that was thought to be well beyond what their astronomical knowledge was at the time. If the alignment had been planned 500 years before the fact, it would mean that Egyptian astronomers were aware of the precessional cycle of Earth's axis and proper motion, something that wasn't actually discovered until the relatively modern times of Edmund Halley, who is credited with its discovery. It still remains a bit of a mystery today.
As for deep sky targets, Draco doesn't offer too much for amateur instruments. However, one in particular is advertised as an excellent sight for small telescopes. NGC 6543 resides within the Draconian borders just west of the Dragon's head and east of Polaris in Ursa Minor. This bright planetary nebula appears star like in binoculars, but under telescopic magnification becomes a blurry disk shaped object. In long exposure photographs a twisted helix shape becomes apparent.
NGC 5866, an 11th magnitude edge on spiral galaxy, is cataloged as Messier 102, though there is no official Messier listing for this object. One of Messier's contemporaries, Pierre Mechain, accidently listed it, though later realized he had duplicated his observation of M 101. NGC 5866 is one of several dozen galaxies inside Draco's borders, though they are all in the range of 11th through 14th magnitudes and therefore, better suited to the larger backyard "light buckets", and even then, only viewable under perfect dark sky conditions.
The constellation Cassiopeia, the easily recognizable "Lazy W", is available year round, circling in a relatively close orbit of Ursa Minor, the Little Dipper and its anchor star, Polaris, the North Star. Cassiopeia has both Milky Way constituents, as well as external deep sky phenomena - galaxies. This duality is not exactly unique to Cassiopeia, but few constellations are blessed with the wealth of both local galactic clusters, thick star fields and extra galactic treasures.
An invisible member within the borders of Cassiopeia is known as Tycho's Star, a supernova remnant first discovered in November 1572. There are just a handful of recorded supernovae, the earliest was witnessed in 1006 in the constellation Lupus. Next came the 1054 supernova in Taurus which is associated with one of the most famous novae remnants in the heavens. I'm referring to the Crab Nebula in Taurus. Lastly, some 32 years after Tycho's Star was detected came the sighting of what is called Kepler's Star in Ophiuchus today.
Supernovae are the most spectacular explosions ever witnessed by man. While regular novae are quite sensational, but also fairly common, the sheer magnitude of the supernovae are astronomical in comparison. Only occurring in extremely large stars, these explosions are furious and, in the case of Tycho's Star, leave nothing where once resided an extraordinary sun. Regular novae occur quite frequently, on the average 30 to 40 per year in our galaxy alone. While supernovae are witnessed on the average of perhaps three or four per millennium. There is evidence (remnants) of about six others occurring within the Milky Way. In external galaxies we have witnessed several, some of which outshine the entire galaxy they reside in.
Besides Tycho's Star, Cassiopeia is filled with sights well worth training a pair of binoculars or a small telescope on. Because it sits partially submerged in the Milky Way, a sweep across this celestial W will reveal thickly populated star fields and clusters of which M-52 is one. This open cluster is comprised of hundreds of tiny stars mixed in with several closer and larger constituents. Containing both red and blue giants, this particular cluster is quite striking in both close up and wide-field views. In the same field of view is another peculiar inhabitant of Cassiopeia, the Bubble Nebula, NGC 7635. This nebulosity which is only accessible through long exposure photographs has been classified as a planetary nebular but speculation still exists as to its exact nature.
M103 is next on our hunt and is one of the last objects on Charles Messier's original list of nebulosities not to be confused with incoming comets. Some have added M104, the Sombrero Galaxy to the list and still others have included as many as six more objects to the "M" list. M103 is the last one Messier included himself, though M. Mchain was actually the first to discover it in 1781. Another fine Cassiopeian sight in wide angle views is the triple cluster combination of NGC 654, 663, and 659. And rounding off the excellent clusters in Cassiopeia is NGC 7789 a dense cluster of small dim stars and, NGC 457, an almost twin of the double cluster in Perseus. This one is an easy target for amateur instruments.
As for extra-galactic targets within Cassiopeia, siblings of the great Andromeda Galaxy, a pair of dwarf galaxies sit just within the constellation's borders. NGC 185 and the more diffuse NGC 147 are both small satellites of the "Great Cloud" (M-31) each at a whopping 2.5 million light years away. Under a dark sky many of these objects are attainable in amateur-grade telescopes, in addition to the massive Milky Way star fields throughout Cassiopeia, which even in binoculars are spectacular to behold.
Camelopardalis, a mouthful of a constellation if ever I saw one! Perhaps easiest to make out as a giant letter C, this area of sky contains several, though very dim galaxies. Not a camel, but a giraffe, Camelopardalis is one of the lesser known and recognized constellations belonging to the circumpolar group. The reason is fairly obvious as most of the stars in this group are quite faint. From the map you can see that the area allotted for the constellation is fairly large compared to the stars that actually belong to the asterism, though, I wouldn't call it a true asterism.
One very interesting note is that this is the direction of where the Voyager II spacecraft is in relation to the constellations. It is the first and most distant man-made object ever to leave our our solar system.
There aren't any Messier objects here, but there are a few NGC items of interest, though, again, they are quite dim and require a larger instrument to get any type of worthwhile view. NGC 1502 is a nice little cluster of stars around 8th magnitude, between Alpha and Beta Cam. In the center of what I've loosely referred to as the asterism, resides NGC 1501, a dim planetary nebula at magnitude 12 which will require at least a 10 inch instrument to even glimpse.
There are also a few faint galaxies here. One, NGC 2403, at magnitude 8.8 according to Burnham's Celestial Handbook, is a face-on spiral which is just outside of what we consider the "Local Group" of galaxies to which our Milky way belongs. A 10 inch scope should pick this up under ideal dark sky conditions. Another, though substantially dimmer, is NGC 2655. A large instrument will be needed to capture this magnitude 11.6 galaxy. It is quite small, only 4 x 4 arc seconds across. Most galaxies in this category are better enjoyed via long exposure photographic based observing.
The circumpolar constellations are a wonderful place to spend an evening of Lawnchair Treasure hunting. Whether seen in the deep of winter or during the pleasant climes of a summer evening, this area literally has something for everyone. As always, with this much booty to be discovered and captured, there'll be more than enough to share. Just don't let anyone hog the eyepiece!
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