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October 12, 2020 - Delicate Dance of Shadows

Delicate Dance of Shadows  Every six months the Earth’s axis of rotation is neither pointing  toward the Sun nor away from it. At these times of equinox, or equal night, the Sun appears directly overhead at the equator at local noon, and days and nights there are exactly 12 hours long. Because Saturn takes much longer to orbit the Sun, an equinox there occurs about every 15 years, but when it does, it sets the stage for a memorable play of light and dark as the shadows cast by Saturn’s moons fall directly on the planet’s rings. In April 2009, four months before Saturn’s equinox, the Cassini spacecraft captured this rare image. The shadow of its moon Tethys falls across the A ring and Cassini Division in this view, which looks toward the unilluminated side of the rings from about 50° above the ringplane.

Image credit: NASA / JPL / Space Science Institute

Weekly Calendar

October 12 - 18, 2020

Holidays - Sky Events - Space History

 

Moon phase Monday 12

Thanksgiving Day (Canada)
Columbus Day

1964: Voskhod 1 launched, first three-person space flight
1977: Shuttle Enterprise’s first glide test without aerodynamic tailcone
2008: ISS Expedition 18 crew launched

Moon phase Tuesday 13

Mars at opposition
Venus 4° south of Moon

1773: Charles Messier observes M-51
1933: British Interplanetary Society founded
1968: Apollo 7 first live TV broadcast from space
2004: ISS Expedition 10 crew launched

Moon phase Wednesday 14

Mercury stationary

1947: World’s first supersonic flight
1957: USAF announces X-20 Dyna-Soar project
1983: Venera 16 arrives in orbit around Venus

Moon phase Thursday 15

1829: Asaph Hall born
1997: Cassini-Huygens launched
2003: Shenzhou 5 launched, Yang Liwei becomes first Chinese astronaut

Moon phase Friday 16

New Moon 3:31 PM ET
Moon at perigee

Moon phase Saturday 17

Mercury 7° south of Moon

1956: Mae Jemison born
2016: Shenzhou-11 launched

Moon phase Sunday 18

1967: Venera 4 makes first direct studies of Venus’s atmosphere
1989: STS-34 Atlantis launched
1993: STS-58 Columbia launched
2003: ISS Expedition 8 crew launched

Suggestions for new history dates or better links? Corrections for errors on this page? Please e-mail me.