Saturday, October 9
Mercury reaches inferior conjunction at 12 P.M. EDT. This puts it essentially directly between the Sun and Earth, rendering the tiny planet invisible. But don’t worry — it will slip away from our star’s glare to reappear in the morning sky later this month.
Instead, try searching the early-morning skies for Comet 67P/Churyumov-Gerasimenko, which skims 1.2° northwest of the famous Crab Nebula (M1) in Taurus the Bull. The magnitude 8.4 supernova remnant lies directly between the comet and 3rd-magnitude Alheka (Zeta [ζ] Tauri), which marks one of the Bull’s horns. 67P is a 10th-magnitude fuzz about 6' across; you should be able to get both it and the nebula in a single telescope field. Binoculars will show an even wider field of view.
While you’re here, follow the line from 67P through M1 and Alheka another 11° southeast and you’ll run smack dab into Comet 4P/Faye, which sits about 1.5° northeast of 4th-magnitude Xi (ξ) Orionis in Orion the Hunter. Faye is a bit fainter (magnitude 11) than Churyumov-Gerasimenko, but roughly the same diameter. It’s traveling southeast against the background stars, compared to Churyumov-Gerasimenko’s, more northeasterly path.
Sunrise: 7:05 A.M.
Sunset: 6:29 P.M.
Moonrise: 10:50 A.M.
Moonset: 8:43 P.M.
Moon Phase: Waxing crescent (14%)
Sunday, October 10
Saturn is stationary tonight at 10 P.M. EDT, when its retrograde motion against the backdrop of faraway stars halts. In the coming days, it will appear to swing around and begin moving eastward, although the motion will be hard to pick up by eye.
The solar system’s second-largest planet is currently located in Capricornus the Sea Goat; it’s rising in the south as the Sun sets and visible all evening, setting just before 1 A.M. local time. That makes the best time to view it around 8 P.M. local time, when it’s highest in the sky. Glowing at magnitude 0.5, it’s on the opposite side of the constellation from brighter Jupiter, which shines at magnitude –2.6. Saturn sits just below the midpoint of a line drawn between Theta (θ) and Beta (β) Capricorni.
Zoom in on the planet tonight and you’ll see that its two-faced moon Iapetus is also at superior conjunction. It now stands about 40" north of Saturn and is roughly magnitude 11. Over the course of the month, it will dim to magnitude 12 as it approaches greatest elongation on the 29th. Several other moons float around the planet as well, including bright Titan 2.5' to its southeast and dimmer Rhea, Tethys, Dione, and Enceladus closer to Saturn and its magnificent ring system.
Sunrise: 7:06 A.M.
Sunset: 6:27 P.M.
Moonrise: 12:07 P.M.
Moonset: 9:30 P.M.
Moon Phase: Waxing crescent (24%)
Monday, October 11
The Moon tonight sits just off the spout of Sagittarius’ Teapot asterism in the south. With a telescope, zoom in on the lunar north to find Mare Frigoris, an elongated sea draped over the larger, rounder Mare Imbrium and Mare Serenitas.
Just beneath Mare Frigoris is the 54-mile-wide (87 km) crater Aristoteles. To its immediate east is the small crater Mitchell, and southeast lies Exodus. Really zoom in on these craters to drink in their immense detail. Aristoteles has no central peak, but instead boasts several smaller mountaintops poking up from its flooded floor. Lighter-colored ejecta sprays off to the crater’s north. Next, look closely at the rim of Exodus to see if you can make out its numerous terraces. This crater, too, lacks a central peak; you’ll instead see a few low hills in the middle of its bowl.
Of course, just what you’ll see and how you will see it will change as the Sun’s angle also changes over the next few hours and days. You’ll want to return to this spot tomorrow and the day after to see how these features appears to morph as the Sun moves over the lunar landscape.
Sunrise: 7:07 A.M.
Sunset: 6:26 P.M.
Moonrise: 1:18 P.M.
Moonset: 10:25 P.M.
Moon Phase: Waxing crescent (34%)