It's fall, or is that Autumn? Why does just this season have two names? Perhaps we should give secondary names to the other seasons as well. Spring: Hop? Summer: Sweat? Winter: I want my mommy!
Many observers complain that there just isn't a whole lot to look at in and around the area of Aquarius and Capricorn. Though this may be the case for some, the Lawnchair doesn't necessarily agree with the statement in its entirety. Perhaps there are only a scant few Messier objects within these constellations, but there are numerous NGC objects viewable in large backyard instruments like Big Red and of course, in the really huge telescopes that the professionals and some fortunate enthusiasts have access to.
In some parts of the world, especially during ancient times, the rising of Aquarius signaled the oncoming monsoon season, as well as the debut of the other Autumnal and Winter constellations. Of course, in more modern times, the "Age of Aquarius" was immortalized during the nineteen sixties by the singing group, The Fifth Dimension. And there is reason to sing about Aquarius and what there is to behold in her arms. Even in small instruments, M-2 is visible as a small, round, fuzzy star. In larger 8 to 10 inch telescopes, this distant cluster will partially resolve into its myriad stars. Only in the largest amateur and professional telescopes will anymore detail be apparent than this. Other clusters in Aquarius include M-72 and M-73. They each reside in extreme western Aquarius, some three degrees W-SW or so of NGC 7009, the Saturn Nebula.
In 1782 William Herschel, while searching through Aquarius came upon this very bright and extraordinary planetary nebula which he appropriately named the Saturn Nebula. In small telescopes, not much more than a small dim cloud will be apparent, impossible to see at all under anything but optimum seeing conditions. In 10 inch or larger reflectors, the ansae, (simulated rings) are visible under dark-sky conditions. The object itself has been described as striking in larger instruments with a vivid green glow caused by strong ultra-violet radiation coming from the central star which shines at a warm fifty-five thousand degrees Kelvin. Distances to planetary nebulae are often guesstimates and this one seems to work out to approximately four thousand light years distance, give or take a hundred light years or so. The problem is partially complicated due to conflicting measurements between the central stars of these types of nebulae and the nebulae themselves.
Another Aquarian nebula, NGC 7293, is one the largest and nearest of the planetary nebulae. As large as half the size of a full moon, this ring shaped object is quite dim having a very low surface brightness. Available in binoculars as a dim, hazy ring under perfect seeing conditions, in small telescopes the Helical Nebula will be best viewed within a wide angle eyepiece. The best instrument to view this target would be any of the "rich field" telescopes with wide angle lenses. In photographs taken with the Palomar 200 inch telescope a wealth of detail wass revealed in this nebula. It's absolutely phenomenal in HST images.
These planetaries are peculiar objects to say the least. There are five hundred known examples, though over ten thousand may exist in our galaxy alone. Many theories abound concerning these enigmatic objects. One proposes that they may possibly be caused by lazy or slow novae processes, instead of the more common and explosively energetic super-novae, which are usually short-lived and typically leave behind hard to detect debris and other relatively short-lived remnants.
Using the hop, skip and jump method, below Aquila and to the southeast (left) of the Teapot of Sagittarius, you'll easily discern the constellation Capricorn. This large arrowhead-shaped constellation points down toward the horizon, and, if you can see down far enough, the small obscure constellation Microscopium which, when seen from the tropics at this time of the year, is quite high in the sky. I guess those responsible for naming constellations ran out of mythological beings and animal names and resorted to using whatever they had around. Microscopium, Telescopium, what's next? Televisionum? Waterbedium? iPhonium? Please, some one stop me!
Capricorn houses the globular star cluster M-30. It can be viewed in amateur grade instruments, ideally though, only when seeing conditions are excellent. Looking through all the atmosphere near the horizon is typically not the best way to see a clear view of any astronomical object. Other than that, the constellation contains a handful of double stars and little else of interest to deep-sky fans.
There are a handful of dim galaxies that reside here, but many more are peppered throughout the other small constellation below and to the east (left) of Capricorn. Piscis Austrinus, the Southern Fish, sibling to its V shaped elder, lies just below Aquarius. Once again, this is a constellation that sits close the horizon for northern observers and, therefore, is often difficult to view and recognize. Of the nine or so galaxies that reside within borders of Piscis Austrinus, the brightest is really dim 12.8 magnitude. You'll need a fairly large instrument even to glimpse any of these. The only thing I'd steer you toward here is its Alpha star, Fomalhaut, which is the 18th brightest star in the sky at just around 1st magnitude. It's not a lot to look at, but besides its few binary stars and variables, this is simply a pretty boring piece of sky for amateur observers.
However, on a historical note, Capricorn is where J. Galle first discovered the planet Neptune. More on that in the chapter on Planet Watching. Fall is indeed another comfortable month for the Lawnchair set. The days begin shortening so an early evening out under the skies is easy enough with plenty of time to catch your favorite prime time television offerings. Hell, it's not like the Lawnchair would feel entirely out of place smack dab in the middle of the living room. Let's just say it wouldn't be the first time!
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