The Sky This Week from November 12 to 19


Monday, November 15

Today we celebrate Frederick William Herschel’s 283rd birthday. The accomplished astronomer made many discoveries during his career, the most famous of which is the planet Uranus.

Cap off Herschel’s big day by enjoying an evening view of the ice giant. Uranus reached opposition earlier this month, so it’s up all night. The best time to look for it is around local midnight when it’s highest in the sky, floating in the constellation Aries the Ram. Look south to find Aries’ brightest star, Hamal, and then locate Menkar, Cetus’ alpha star, about 23° to its southeast. Uranus lies roughly halfway between these stars, about 1.5° west-southwest of 6th-magnitude Omicron (ο) Arietis.

Shining at magnitude 5.7, the distant planet is visible with the naked eye under dark-sky conditions. However, depending on your location and with the waxing Moon nearby in Pisces, you’ll likely need binoculars or a small scope to spot its 4″-wide, blue-green disk. The distant ice giant is currently some 1.75 billion miles from Earth.

Sunrise: 6:45 A.M.
Sunset: 4:43 P.M.
Moonrise: 3:14 P.M.
Moonset: 2:59 A.M.
Moon Phase: Waxing gibbous (88%)

Tuesday, November 16

Have you ever seen a demon star? It lurks in Perseus the Hero, rising in the northeast by sunset.

The star in question is Algol, also cataloged as Beta (β) Persei. This bright star is in an eclipsing binary system, meaning its companion passes between it and Earth every orbit, dimming the light we see. In Algol’s case, this occurs every 2.867 days, making the star dip from magnitude 2.1 to 3.4 — that’s a change of 30 percent, enough to notice with the naked eye.

You’ll find the so-called Demon Star, which depicts the severed head of the gorgon Medusa in the constellation’s figure drawing, about 18.5° northwest of the Pleiades in Taurus. Algol is located 93 light-years away and consists of a star some 3.5 times the width of our Sun that is eclipsed by a smaller star about 2.9 times the diameter of the Sun. (In fact, there is at least one more component of this system, which orbits the inner pair every 1.86 years.)

So, step outside tonight and take note of Algol’s brightness compared to the stars around it. Then come back each night for the next few days and observe how it has changed. When uneclipsed, Algol is as bright as nearby Mirfak (Alpha [α] Persei). But during an eclipse, it is clearly fainter.

Sunrise: 6:47 A.M.
Sunset: 4:42 P.M.
Moonrise: 3:37 P.M.
Moonset: 4:00 A.M.
Moon Phase: Waxing gibbous (94%)

Wednesday, November 17

The Leonid meteor shower peaks today, but the bright Moon will make spotting shower meteors nearly impossible. If you missed your chance to search out shooting stars earlier this week, wait a few days until the Moon begins waning, then try again during the early morning predawn hours, when Leo is highest in the sky. The shower lasts until November 30th — but remember that it’s weak and not likely to produce a large number of meteors above the sporadic background limit. Plus, the waning Moon will still grace the early-morning skies, adding some unwanted light.

Speaking of our satellite, the Moon passes 1.5° south of Uranus at 9 P.M. EST tonight. The pair shines in Aries, which is bordered by the constellations Cetus, Pisces, Triangulum, Perseus. Taurus, and Eridanus. Although the Moon will be bright, you can still catch a glimpse of Uranus through binoculars or a telescope. It’s currently 11.3° northwest of a 7th-magnitude field star, HIP 12349.

While you’re in the area, you might also zoom in on clusters such as like the Pleiades and the Perseus Double Cluster, which will be visible — if somewhat diminished — by the bright moonlight.

Sunrise: 6:48 A.M.
Sunset: 4:42 P.M.
Moonrise: 4:00 P.M.
Moonset: 5:01 A.M.
Moon Phase: Waxing gibbous (97%)

Thursday, November 18

Saturn’s two-faced moon Iapetus reaches inferior conjunction today, appearing closer to the ringed planet than usual. Turn a telescope toward Capricornus after dark to see the 11th-magnitude moon roughly 34″ south of Saturn. Its darker face is currently turned toward us, but that’s changing — its lighter side will rotate into view for the second half of the month, so come back to check in on the moon in a week or two to see how its brightness has changed.

More easily visible is Saturn’s largest moon, Titan, sitting 2.8′ due west of Saturn and glowing at magnitude 8.7. Over the next few days, its orbit will carry it northeast (counterclockwise), until it sits due north of the planet on the 22nd.

Don’t forget — how could you? — to also stop and admire Saturn’s rings, which span about 38″ (compared to the disk, which stretches only 17″ across).

Sunrise: 6:49 A.M.
Sunset: 4:41 P.M.
Moonrise: 4:26 P.M.
Moonset: 6:01 A.M.
Moon Phase: Waxing gibbous (99.6%)

Friday, November 19

With the Moon well over 99 percent illuminated, the stage is set for a near-total lunar eclipse visible across the entire U.S., including Alaska and Hawaii. It’s worth staying up late on the 18th or getting up early on the 19th (depending on your time zone) to view at least some of it. As a bonus, this is the longest partial lunar eclipse that will occur this century, so it should be easy to catch!

The Moon first slips into Earth’s outer shadow (penumbra) around 1 A.M. EST (10 P.M. PST on the 18th, for those on the West Coast). An hour later, the Moon enters the darker inner shadow (umbra) and the partial eclipse begins. This is when the Moon will start growing noticeably dimmer and take on an orange or reddish hue — the exact color varies, depending on the conditions in Earth’s atmosphere during any given eclipse.

The eclipse will take several hours, reaching maximum around 4 A.M. EST (1 A.M. PST), when Earth’s umbra will cover roughly 98 percent of our satellite. Only a small portion of the Moon will remain outside the umbra. This is just after the time Full Moon officially occurs, which is 3:57 A.M. EST. (November’s Full Moon is also called the Beaver Moon.)

The partial phase of the eclipse ends just before 5:50 A.M. EST, with the penumbral phase ending around 7 A.M. EST.

If you recall, last November featured a lunar eclipse as well, but this was a penumbral eclipse, during which the Moon only passed through the outer region of Earth’s shadow for a much less dramatic effect.

Sunrise: 6:50 A.M.
Sunset: 4:40 P.M.
Moonrise: 4:56 P.M.
Moonset: 7:03 A.M.
Moon Phase: Full





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