2025, January 23:  Vega Doubletake

January 23, 2025:  Vega appears in the eastern sky before sunrise and in the western sky after sundown – a Vega doubletake.

Comet NEOWISE, July 11, 2020
2020, July 11: Comet NEOWISE shines from low in the northeast sky during early morning twilight. It is to the lower left of the star Capella.

Chicago, Illinois: Sunrise, 7:11 a.m. CST; Sunset, 4:55 p.m. CST.  Check local sources for sunrise and sunset times. Times are calculated by the US Naval Observatory’s MICA computer program.

Nightly Planet Display

Venus, Saturn, Moon, January 3, 2025
Photo Caption – Venus, Saturn, Moon, January 3, 2025

The bright nightly display of four bright planets continues.  After sundown, brilliant Venus is above Saturn in the southwest.  Bright Jupiter is high in the east-southeast, while Mars is with the Gemini Twins.

Vega Doubletake

Vega Doubletake
Chart Caption – 2025, January 23: Vega and Deneb are in the eastern sky before sunrise.

An interesting effect occurs with the star Vega at this season.  The star is visible before sunrise and again after sunset.  With the sun so far southward, it is in the sky for less than 10 hours.  In contrast, Vega is in the sky for over 18 hours.

Vega Doubletake
Chart Caption – 2025, January 23: Bright Vega and Deneb are in the northwestern sky after nightfall.

Vega rises in the east-northeast several hours before daybreak.  It stands halfway up in the east-northeast an hour before sunrise.  As the sky brightens from daylight Vega moves westward during the day from Earth’s rotation.  After sundown, the star is low in the west-northwest – a Vega doubletake.

The same occurs with Deneb, the tail of Cygnus. It is farther north than Vega and stays in the sky even longer.  Deneb is to Vega’s lower left in the morning and to the upper left after sunset.

Stars, like the Big Dipper, are even farther north and they never set from the mid-northern latitudes and northward, known as the circumpolar stars.  The same works in the southern hemisphere for sky watchers at the mid-southern latitudes and southward.

Vega is the second brightest star in the northern half of the sky; that is, north of the celestial equator.  Earth’s equator is a great circle that is halfway from the poles.  The celestial equator is a great circle in the sky above Earth’s equator and midway from the one celestial pole to the other. 

Sirius

Venus, Procyon, and Sirius, September 26, 2015
Photo Caption – Venus, Procyon, and Sirius, September 26, 2015

Sirius, the night’s brightest star, is south of the celestial equator.  For southern hemisphere sky watchers, its celestial location effects its length of time in the sky.  About the time Sirius is at its heliacal rising in the northern hemisphere, the Dog star appears during the evening as well as before sunrise.

During the next several evenings, Sirius rises at sunset, at Chicago’s latitude, and sets 10 hours later.

The Vega doubletake occurs for Arcturus, the brightest star north of the celestial equator, and Capella, the third brightest.  Arcturus’ double appearance occurs during the autumn, while Capella’s occurs during spring. Capella is in the eastern evening sky, the bright star to Jupiter’s upper left.

Deneb is the 9th brightest star north of the celestial equator.  Along with Vega its dual appearance occurs during winter.

Look for Vega before sunrise and after sunset.

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