Upcoming Sky Events
The Planets
Now is the time of celestial transition. Notice the Milky Way stretching from the southwest to the northeast, cutting the sky in two. To the west of the Milky Way the Summer constellations are beginning to set while our friends of Winter begin their climb into the night sky. Soon our nights of shirtsleeve observing will be gone until Spring. But don’t fret, the Fall and Winter skies hold tremendous treasures to behold.
As October opens, the morning sky is witness to a planetary traffic jam, but first, get ready to say goodbye to Jupiter. It currently shines at -2.0 mag low in the southwest and sets only three hours after the sun. By the end of the month it sinks into the horizon soon after twilight ends. On the 15th, look for a pretty triangular arrangement of a 4-day-old crescent moon, Jupiter, and Antares. It hangs on until mid-November, but at November’s end, Jupiter is gone for 2007.
Mars is rising an hour before midnight as October opens, shining at zero-mag in Gemini. By the end of the month, Mars brightens to -0.6 and rises at mid-evening. At mid- November, Mars begins its retrograde movement, signaling that opposition is just weeks away. The red planet is now 13 arcseconds wide, large enough for telescope observation.
Venus rises in east-northeast well before morning twilight and beams at -4-4 mag. It reaches greatest elongation (46 degrees west of the Sun) on the 28th when it rises almost four hours before the Sun and presents itself 40 degrees above the horizon at sunrise. Its half-moon shape is almost 24 arcseconds wide. In November, the green planet begins a slow descent toward the dawn, but still rises 3.5 hours ahead of the sun.
Saturn is much dimmer, at only 0.8 mag, but its ring system spans 37 arcseconds. By the end of October, Saturn rises five hours ahead of the Sun and will soon move into the evening sky again. By mid-November, the ringed planet rises at midnight and approaches the meridian at dawn. Even though it is still several months from opposition, Saturn is an impressive sight in our telescopes.
Deep Sky
For our deep sky study, I thought we might concentrate on the graceful Swan flying almost directly overhead. Because the Swan flies right down the Milky Way, there a number of interesting deep sky objects close-by. But rather than observing the old familiar Messier objects, let’s look at some of the less observed objects.
Use your favorite star chart to locate these hidden treasures of Cygnus. Begin with NGC 6819, a small open cluster. It is so full of faint stars that its total brightness is 7.3 appearing as a misty patch with a few pinpoint stars in 14x70 binos. It can be easily identified in 4-inch scopes, which reveal about 25 stars. A 10-inch scope will double the number of resolvable stars. This cluster is approximately 2.5 billion years old.
The next target is NGC 6888, the Crescent Nebula. A 4- inch scope at about 50x reveals a northeast-southwest oriented numeral 3 of nebulosity with the northeastern half running through three bright stars. An O-III nebula filter will slightly improve the image. 10-inch and larger scopes fill in the nebulosity, revealing a thumbprint shaped planetary nebula centered on a hot blue-white star that may appear pink.
Next look for NGC 6857, a small but fairly bright emission nebula. In a 4-inch scope at 25x, it appears as a little fuzzy spot with a faint star at one edge. Increasing the magnification to around 85x makes the nebula stand out. In a 10-inch scope at 150x+, reveals the nebula surrounded by a kiteshaped 4-star formation with a center star that makes the asterism appear as a miniature cross. Increasing the magnification to 300x with an O-III filter reveals an even greater expanse of nebulosity.
Another often missed object is NGC 6894, a tough little planetary nebula that forms an isosceles triangle with stars 39 and 41 Cygni. At approximately 50x in a 4-inch scope, the nebula is only visible with averted vision. Increasing the magnification to 85x with an O-III filter makes the object easier to see, but provides no detail. At 150x with a nebula filter, the nebula appears to have a darken area in the middle. A 10-inch scope at 210x reveals a wide patchy ring.
(Info
extracted from
Astronomy
and
Night Sky
magazines and other resources)
Upcoming events information is provided by Robert Lambert