The Sky This Week: Venus blazes bright

Friday, November 19
Early risers this morning can catch the longest partial lunar eclipse of the century, during which some 98 percent of our satellite slides into Earth’s shadow. The effect is a deep red-colored Moon.

If you didn’t get a chance to watch, don’t worry — astronomy livestreamer David Brewer filmed the entire event from Denver, Colorado.

Full Moon occurs this morning at 3:57 A.M. EST. November’s Full Moon is also called the Beaver Moon.

If you’re more of an evening observer, you’re in luck: The sky has another show in store for us tonight, this time as a brilliant planet Venus sits a half-Moon’s width from 2nd-magnitude Nunki in Sagittarius. Look south just after sunset to find a three-planet tableau, consisting of Venus farthest west, then Saturn 26° to its east, and Jupiter another 16° east of the ringed planet.

Venus shines brightest at magnitude –4.8 — you absolutely can’t miss it. Zoom in with a telescope, and you’ll see that its 33"-wide disk is just 40 percent lit. Moving east into Capricornus, Saturn is a much fainter magnitude 0.6. Its largest moon Titan sits just over 2.5' west-northwest of the planet tonight, shining around magnitude 8.7. Finally, Jupiter lies in eastern Capricornus, glowing at magnitude –2.3 and located 1.5° north of magnitude 2.9 Deneb Algedi.

Saturday, November 20
The Moon reaches apogee, the farthest point in its orbit around Earth, at 9:13 P.M. EST. At that time, our satellite sits 252,450 miles (406,279 kilometers) away.

Just a bit past Full, the Moon rises in the east about an hour after sunset. Its bright light will wash out much of the sky around it, but that just means now is a great time to take a tour of some of its nearside features.

Of course, Full Moon (or nearly Full Moon) can be a difficult time for lunar observing. With the Sun high overhead from the viewpoint of the lunar landscape, shadows are minimal and some features are washed out. But that doesn’t mean the endeavor is a wash. Because the Moon is just a little past Full, focus in on the area where night has begun to fall on its eastern limb (which is west on the sky). Particularly stark will be the eastern edge of Mare Crisium, a large, circular basin about 3.9 billion years old. Visible to its south is the large crater Langrenus, which is still fully lit but whose high walls and central peak offer some shadowed terrain.

Sunday, November 21
Cassiopeia the Queen holds our target for tonight: M52, sometimes called the Scorpion Cluster. This open cluster can be a bit hard to find, simply because it’s laid out against the glittering background of the Milky Way.

First find the familiar W of Cassiopeia, an easy-to-spot asterism in the northern sky. Beta (β) Cassiopeiae, also called Caph, is the northwestern most tip of the W, and will guide us right to M52. Simply draw a line from Alpha (α) Cassiopeiae, or Shedar, through Caph, and follow it in the same direction for just a bit more than the same distance. There, about 6° northwest of Caph, is our Scorpion. In binoculars or even your finder scope, it will appear as a fuzzy patch; small (4-inch) scopes will begin to resolve its stars, with a few particularly bright (magnitudes 7, 8, and 11) luminaries present.

Overall, M52 glows around magnitude 7 and spans roughly 13' on the sky. It was cataloged by Charles Messier in 1774, after a comet that year had passed near this young group of stars.

Monday, November 22
Tonight, let’s turn our gaze toward Pegasus, already high overhead after sunset. Near the western edge of this constellation is the globular cluster M15. This ancient swath of stars holds an added bonus: Pease 1, the first planetary nebula discovered inside a globular cluster.

M15 sits just over 4° northwest of 2nd-magnitude Enif, which marks the end of the Winged Horse’s nose. If you’re using binoculars or a small scope, the cluster will look like a fuzzy cotton ball hanging against the dark background of the sky. M15 glows at magnitude 6.2 — just visible with the naked eye from a dark site on a dark night — and spans about 18' across. It sits about 33,600 light-years away.

Pease 1 can be seen in amateur instruments, but you’ll need a large scope with an aperture of at least 12 inches, and more likely 16 to 20 inches to net a reliable sighting. Alternatively, you can set up your camera (or smartphone) to take a long-exposure image, which will collect many more photons than your eye and more easily bring out the planetary’s soft glow. The SEDS Messier site has a helpful finder chart if you’re interested in this challenge.

Tuesday, November 23
Tonight brings us a rare double shadow transit across Jupiter, as its moons Ganymede and Callisto both project dark spots on the jovian cloud tops at the same time.

East Coast observers get the first taste at 6:08 P.M. EST, when Ganymede’s shadow slips onto the planet’s disk. Callisto’s shadow follows at 6:52 P.M. EST. Both moons, however, sit far off to Jupiter’s west, with Ganymede closest to the planet, followed by Callisto, Europa, and then Io.

The two shadows traverse the disk slowly; Ganymede’s shadow exits at 9:39 P.M. EST, while Callisto’s takes over an hour more to finish its journey. You’ll see this second shadow disappear at 11:03 P.M. EST — after the planet has set in that time zone, but while it is still visible farther west.

Wednesday, November 24
Early risers this morning can find the constellation Corvus the Crow, whose easy-to-spot boxy shape is rising in the southeast a few hours before sunrise. See if you can pick out its four main stars, which shine between magnitude 2.5 and 3: Delta (δ), Gamma (γ), Epsilon (ϵ), and Beta Corvi. Curiously, the constellation’s alpha star is much fainter — magnitude 4 — and sits some 2° south of Epsilon.

Delta, also called Algorab, is a double star whose components are a wide 24.2" apart — simple to split with a small telescope. The brighter, 3rd-magnitude primary appears blue-white, while the much fainter, 9th-magnitude secondary appears orange.

Algorab is also one of two pointer stars you can use to skip from Corvus to the brightest star in nearby Virgo. Simply draw a line from Gamma Corvi (also called Giena) through Algorab, then continue in the same direction about four times the distance between the two stars. You’ll land smack-dab on Spica’s brilliant 1st-magnitude glow.

Thursday, November 25
Last year, the popular Astronomy Picture of the Day website reimagined the famous Orion Nebula (M42) as the Great Turkey Nebula in honor of Thanksgiving. Although there is no giant turkey in the sky (only on your table, for those who celebrate), the Orion Nebula remains one of the autumn sky’s best sights, and it’s worth taking a peek after you’ve finished your coffee and pumpkin pie.

Orion’s Belt just is clearing the horizon around 7:30 P.M. local time these days. Wait at least an hour or two, then step outside to find its three stars: Mintaka, Alnilam, and Alnitak (from west to east). The Orion Nebula itself lies in the sword asterism and sits a little less than 4° south of Alnitak. It’s bright enough (magnitude 4) to see with the naked eye, but really pops with binoculars or a telescope. This vast star-forming nursery spans about 85' by 60' and is located about 1,000 light-years from Earth. If you zoom in on its center, you’ll spot the Trapezium cluster, comprising several young, hot, massive stars. The four brightest stars are easy to see in a small scope. These stars are so hot and bright that their radiant light is clearing away the gas and dust of the nebula that birthed them.

Take some time to digest this stunning deep-sky wonder — and consider whether you think it’s turkey-shaped or not.

Friday, November 26
Dwarf planet 1 Ceres, the largest body in the main asteroid belt, reaches opposition at 11 P.M. EST tonight. That means it’s up all evening, hiking across the Hyades star cluster that marks Taurus the Bull’s nose. The best time to view it is late in the evening, once the constellation has climbed high above the horizon.

At magnitude 7.7, Ceres is within easy reach of binoculars or any small scope, especially from a dark location. If you’re in the city, your binoculars might have a bit of trouble, but your scope will pick it up readily. Tonight, the dwarf planet forms one point of an equilateral triangle with 3rd-magnitude stars Delta and Gamma Tauri. Ceres is moving slowly, so you probably won’t notice its motion over the course of a single night. But keep coming back over the next few days, and you may be able to pick out its sideways march as it moves from east to west.