NGC 7293, the "Helix Nebula" in Aquarius, imaged 2022 October 30 at Sky Meadows State Park, Paris, Virginia
with an Explore Scientific AR102 10.2-cm (4-inch) f/6.5 refractor, Optolong L-eNhance filter, annd a ZWO ASI183 CMOS color imager
The Moon retreats into the early morning skies this week, climbing northward along the ecliptic as she moves through the rising winter constellations. Last Quarter falls on the 16th at 6:27 am Eastern Standard Time. Look for Luna near the Pleiades star cluster in the late evening hours of the 8th and 9th. On the 10th she rises close to ruddy Mars. Her waning gibbous will be near Castor and Pollux, the Twin Stars of Gemini, during the overnight hours of the 13th.
The return to Standard Time means that skywatchers get a leg up on nighttime viewing. The end of evening twilight now occurs at around 6:30 pm local time, allowing for several hours of dark sky enjoyment while still allowing for a decent bedtime. The early evening hours still feature some of the bright stars of the summer sky while the Milky Way bisects the celestial dome from southwest to northeast. Look for the bright stars of the Summer Triangle, Vega, Altair, and Deneb, hovering high over the western horizon at around 7:00 pm. There are many interesting celestial sights in this part of the sky, and at this time of the year they aren’t affected by the haze and humidity characteristic of summer. Somehow the yellow and blue colors of the double star Albireo seem crisper in autumnal skies, and the star clouds of the Milky Way have a little extra contrast in my binoculars.
By 9:00 pm the autumnal constellations take center stage, marked by the distinctive “Great Square” of Pegasus. Below the square are a number of dim “water” constellations including Capricornus, the Sea-Goat, Aquarius, the Water Bearer, Pisces, the Fish, Cetus, the Sea Monster, and Pisces Austrinus, the Southern Fish. Of these, only the latter two have fairly bright stars, Diphda and Fomalhaut, respectively. Diphda is a giant star located about 96 light-years away and represents a type of star that has evolved through its “red giant” phase and is now fusing helium into heavier elements in its core. In about 100 million years it will exhaust the helium in its core and collapse into a so-called “planetary nebula”. A fine example of such an object exists among the dim stars of Aquarius. Known as the “Helix Nebula”, it is located some 650 light-years from us and may be glimpsed as a faint glowing patch of light in small telescopes. About 10 degrees south of the Helix Nebula is the star Fomalhaut, which is the most isolated of the first-magnitude stars. Its claim to fame is that it was the first star known to have several “debris disks” orbiting its equatorial plane. These disks received intense scrutiny in the early 2000’s, when the Hubble Space Telescope imaged what was thought to be a planet embedded in the dust. Later study seems to indicate that this purported planet is more likely a large dust cloud.
The return to Standard Time now puts Saturn on the meridian at around 6:00 pm local time, so you can have a good look at him before sitting down for dinner. It’s also a good time to share the view with your friends, neighbors, and especially kids. I have found in my years of doing astronomy from my front yard that there are few views through the telescope that elicit expressions of amazement and wonder as a person’s first sight of the ringed planet in the eyepiece. “Wow! It looks just like the pictures!” is music to my ears.
Jupiter continues to lord over the evening sky. He crosses the meridian at around 8:30 pm now, prime time for evening viewers. The giant planet is also a crowd-pleaser, mostly due to the visibility of his four brightest moons, first described by Galileo in 1610. The configuration of these nearly planet-sized bodies is constantly changing, and you can actually see their motion in “real time” when two approach each other from opposite directions. A four-inch telescope will also show the shadows of the moons as they pass between Old Jove and the Sun. On nights of steady air, study the planet’s raging cloud belts and spots as the planet’s rapid rotation carries them across his disc.
By 10:00 pm another bright planet begins to dominate the eastern sky. Ruddy Mars is now second only to Jupiter in brightness. He is high on the ecliptic to the east of the star Aldebaran in Taurus, the Bull. Mars will continue to brighten as his opposition approaches a month from now. If you have a telescope of six inches aperture or more, now is the time to start examining his subtle surface features. Other than the Moon and Mercury, the surface of Mars is the only actual planetary surface that we can see from Earth.