Crescent Moon near Jupiter and Saturn (Chris Vaughan, Starry Night Education)
This Week’s Sky: November 16 to 22, 2020

This week, look for the peak of the Leonids Meteor Shower, variable star Algol’s minimum, and a pretty meetup between Jupiter, Saturn and the crescent Moon.

Tuesday, November 17 – Leonids Meteor Shower peaks (all night)

Leonids Meteor Shower peaks (Chris Vaughan, Starry Night Education)

The Leonids Meteor Shower, derived from material left by repeated passages of periodic Comet 55P/Tempel-Tuttle, runs from November 5 to December 3 annually. The peak of the shower, when up to 20 meteors per hour are predicted – many with persistent trains – will occur at 23:00 GMT on Tuesday, November 17 – when Earth will be traversing the densest part of the comet’s debris train. For observers in the Americas, the best viewing times for Leonids are Tuesday and Wednesday morning before dawn, when the radiant in Leo will be high in the eastern sky. A young, crescent moon on the peak date will set after sunset, leaving the overnight sky nicely dark for meteors.  

Wednesday, November 18 – Algol at minimum brightness (at 6:55 p.m. EST)

Algol at minimum brightness (Chris Vaughan, Starry Night Education)

Algol, also designated Beta Persei, is among the most accessible variable stars for skywatchers. Its naked-eye brightness dims noticeably for about 10 hours once every 2 days, 20 hours, and 49 minutes because a dim companion star orbiting nearly edge-on to Earth crosses in front of the much brighter main star, reducing the total light output we receive. On Wednesday, November 18 at 6:55 p.m. EST (or 23:55 GMT), Algol will reach its minimum brightness of magnitude 3.4, which is almost exactly the same as the star Rho Persei that sits two finger widths to Algol’s right. At 6:55 p.m., for observers in the Eastern time zone, Algol will sit 40 degrees above the northeastern horizon. Five hours later, at 11:55 p.m. EST (or 6:08 GMT), Algol will be high in the eastern sky, and will have brightened to its usual magnitude of 2.1.

Thursday, November 19 – Crescent Moon near Jupiter and Saturn (early evening)

Crescent Moon near Jupiter and Saturn (Chris Vaughan, Starry Night Education)

In the southwestern sky for a few hours after sunset on Thursday, November 19, the waxing crescent moon will pay its monthly visit to the gas giant planets Jupiter and Saturn – forming a squat triangle with dimmer Saturn at the top. The trio will make a lovely photo opportunity when composed with some interesting foreground scenery.

Saturday, November 21 – First quarter Moon (at 11:45 p.m. EST)

First quarter Moon (Chris Vaughan, Starry Night Education)

When the moon completes the first quarter of its orbit around Earth at 11:45 p.m. EST on Saturday, November 21 (or 4:45 GMT on November 22), the relative positions of the Earth, sun, and moon will cause us to see it half-illuminated – on its eastern side. At first quarter, the moon always rises around noon and sets around midnight, so it is also visible in the afternoon daytime sky. The evenings surrounding first quarter are the best for seeing the lunar terrain when it is dramatically lit by low-angled sunlight.

Chris Vaughan is a science writer, geophysicist, astronomer, planetary scientist and an “outreach RASCal.” He writes Astronomy Skylights, and you can follow him on Twitter at @astrogeoguy. He can also bring his Digital Starlab portable inflatable planetarium to your school or other daytime or evening event. Contact him through AstroGeo.ca to tour the universe together.

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