by Geoff Chester, USNO Public Affairs | 25 October 2022 NGC 6960, the "Witch's Broom Nebula" in Cygnus, imaged 2022 August 13 from Alexandria, Virginia. with an Explore Scientific AR102 10.2-cm (4-inch) f/6.5 refractor, Optolong L-eNhance narrowband filter, and a ZWO ASI183MC color CMOS imager The Moon returns to the evening sky this week, skirting the southern horizon as she passes from the setting summer constellations into the sparse star fields of autumn. First Quarter occurs on November 1st at 2:37 am Eastern Daylight Time. Look for Luna’s crescent nestled among the stars of the “Teapot” asterism of Sagittarius on the evening of the 29th. On the evening of the 1st you will find her just under five degrees south of yellow-hued Saturn. The crisp nights of autumn remind us that winter will soon be upon us, and this week we observe the beginning of that transition with the observance of the year’s most popular “cross-quarter” days. These traditional dates are important markers of the seasonal calendar, falling more or less half way between the equinoxes and solstices. Each of these dates were important feast days in various Pagan traditions, and they are still widely observed in many northern European cultures, particularly those of Celtic origins. As Christianity swept across the Continent, many of these ancient celebrations were adapted to fit the annual calendar of holy days associated with saints. The Gaelic celebration of Samhain was a harvest festival that marked the beginning of the darker half of the year, which began on November 1st. It was a time to venerate those who had died during the previous year and to bless those who were left behind. Christians adapted the date to celebrate All Saints Day, with the previous evening opening the festivities as All Hallows Eve. However, old traditions can persist, so both dates also invoke the memory of departed souls from the previous year. The secular observance of Halloween recalls these ancient roots, as ghosts and goblins prowl the streets looking for sweet supplications. Halloween is undoubtedly the most familiar of the cross-quarter days from the old traditional calendars. We still observe others as Groundhog Day, May Day, and to a lesser extent Lammas Day. In many ways they are more indicative of the seasons that they represent than the more traditional markers of the equinoxes and solstices. If you have a telescope, set it up to give trick-or-treaters a special treat beyond the usual candy. The Moon offers a perfect target for youngsters (and their parents) for what may be their first glimpse at the surface of another world. Any small telescope will give a good view of our natural satellite. If you have a larger instrument, consider pointing it at Saturn. I have yet to find anyone who has not reacted with amazement at their first view of the distant planet. There are a plethora of other spooky objects to entertain night visitors as well. Last week we mentioned the “Demon Star”, Algol, which is normally the second-brightest star in the constellation of Perseus. As the prototype eclipsing binary star, its 2.87-day period has been observed for millennia. The star represents the “evil eye” of one of mythology’s most fearsome creatures, the gorgon Medusa, who had venomous snakes for hair and could turn creatures into stone with her gaze. The large constellation of Cetus, which occupies a chunk of the sky south of Pegasus, was depicted in old star atlases as something resembling a whale with a large beak and a horn in the middle of its forehead. Pore over a list of constellations and you will find a dragon, a sea serpent, and a couple of centaurs. Perhaps my favorite object in this season’s sky is a faint wisp of light in the constellation of Cygnus, the Swan. Known as the “Witch’s Broom Nebula”, it is part of a vast bubble of slowly expanding gas unleashed by a supernova explosion that took place some 10,000 years ago. Saturn reached the second stationary point in its current apparition on the 23rd. For the rest of the year the ringed planet will gradually move eastward through the “tail” of Capricornus, the Sea-goat, yet another sea monster inhabiting the autumn sky. Saturn will slowly creep toward the constellation’s brightest star, Deneb Algeidi, and its naked-eye “companion” Nashira as the year winds down. The waxing Moon passes south of Saturn on the evening of the 1st. Jupiter shines prominently in the evening sky. I happened to notice him last week just after sunset, and for a moment I thought his bright glow was an airplane approaching National Airport. He is well placed for telescopic perusal at the end of evening twilight and transits the meridian at around 10:30 pm local time. Look for his two innermost Moons, Io and Europa, close to the planet’s limb on Halloween. They will move closer to the planet during the evening, and disappear behind the planet’s enormous bulk between 10:00 and 10:30 pm EDT. Mars reaches the first stationary point in this current apparition on the 30th. He will gradually begin to retrograde through the stars of Taurus, the Bull as Earth catches up to him before passing between him and the Sun on December 8th. You’ll find his bright ruddy glow among the rising stars of the Great Winter Circle as the midnight hour approaches.