What's In The Sky — October 2017
October nights will be full of celestial treats to see with binoculars and telescopes. Here are some of our top October stargazing suggestions:
Deep Sky Treats of October
In early October, catch your last glimpse of the year of the galactic center in the constellation Sagittarius, low in the southwestern sky, where you can track down four great emission nebulas — M8, the Lagoon; M20, the Trifid; M17 the Omega; and M16, the Eagle.
Two great planetary nebulas are still well-placed in October skies — M57, the Ring Nebula in Lyra; and M27, the Dumbbell Nebula in Vulpecula.
Look for interesting galaxy NGC 7331 in the northwestern section of Pegasus. With a 12" or larger aperture telescope and good seeing conditions, you may be able to tease out the galaxy's faint spiral arms.
Regulus Hides Behind the Moon
Before dawn on October 15th, the Moon will pass in front of Regulus, the brightest star in the constellation Leo. During this occultation, blue-white Regulus will disappear behind the bright side of the waning crescent Moon and reappear past the dark limb approximately one hour later. This occultation of the "Heart of the Lion" star will be visible across most of the United States, except along the West Coast.
Time to (Star) Party
Get ready to stargaze on October 19th since the night sky will be free of the Moon's bright glare thanks to the New Moon. This will be the best night of the month to use a telescope to go after views of faint deep sky objects. Make the most of the New Moon and plan a trip to your favorite dark sky site with friends and family.
Best Chance to See Distant Uranus
Take advantage of the dark skies courtesy of the New Moon to catch a glimpse of elusive planet Uranus as it reaches opposition on October 19th. With Earth positioned between Uranus and the Sun along a roughly straight line, opposition is when Uranus will be in its orbit's nearest point to Earth. Grab a star chart or StarSeek app to track down this magnitude 6.5 planet, which is just below naked-eye visibility, in the constellation Pisces. Since it's so far away from Earth, Uranus will be a very small bluish-green dot in large telescopes. While sighting the ice giant planet can be a challenge, it's worth the effort to know you're looking at one of the most distant planets in the Solar System.
Fabulous Fall Star Clusters
Nestled between constellations Aries and Taurus is the famous "open" star cluster M45, also known as the Pleiades or Seven Sisters. The Pleiades cluster is an excellent target for binoculars, since telescopes are usually too powerful to provide a view of the entire cluster in one field-of-view.
About a hand's width southeast of the Pleiades is an association of brighter stars called the Hyades, which covers about 5° of the sky with stars laid out in the shape of a "V," pointing west and slightly south. Since it covers such a wide swath of sky, the Hyades is another great object to explore with big binoculars.
Low in the northeast skies of October, pick out the constellation Auriga; then using a star chart, see if you can pick out the three star clusters Auriga hosts — M36, M37 and M38 — all in a row. While these clusters are all visible with a telescope, you can also explore them with 50mm or larger binoculars from a dark sky site.
Orionid Meteors in the Sky
The Orionids is a medium shower that can display anywhere from 10 to 20 meteors per hour at maximum. While the peak of the Orionids shower is hard to precisely predict, the best time to look for meteors will be after midnight on the evening of October 21st into the morning of the 22nd. Meteors will appear to radiate outwards from the upraised club section of our namesake constellation, Orion the Hunter.
A Grand Galaxy
Located in the tiny constellation of Triangulum and just opposite the star Beta Andromeda is the splendid galaxy M33. While the galaxy is visible in [binoculars] with 50mm or larger lenses from a dark sky site, a telescope at low power will provide the best views. M33 has very low surface brightness, so look when the Moon is down and from the darkest sky site you can find!
A Challenging Nebula
Making a small equilateral triangle with the stars Eta and Alpha Cassiopeia is the elusive Pac Man Nebula, NGC 281. The Pac Man is a famous target for astrophotographers, but it's not very easy to observe visually. From dark sky locations, you can pick out its faint glow with large binoculars, but a telescope at low power with the help of an Oxygen-III filter will show it best.
All objects described above can easily be seen with the suggested equipment from a dark sky site, a viewing location some distance away from city lights where light pollution and when bright moonlight does not overpower the stars.