Skywatching January 2013


The great winter constellation Orion appears in the eastern sky
during early evening hours this month.


During January, daylight increases by nearly an hour.  Throughout the month, the sun rises after 7 a.m. in the Chicago area.  Early in the month, the sun sets around 4:30 p.m. and by month’s end, it sets after 5 p.m.  This occurs because the sun appears higher in the sky each day.  The higher the sun is in the sky at noon, the longer it stays in the sky.






Last 01/04 11:14 p.m. (01/03) 10:54 a.m.
New 01/11 6:49 a.m. 4:59 p.m.
First 01/18 10:45 a.m. 12:46 a.m. (01/19)
Full 01/26 4:54 p.m. 6:59 a.m. (1/27)

Moonrise and Moonset times for Chicago, Illinois, from the U.S. Naval Observatory.  All times Central Standard Time.

Evening Sky

The Giant Planet Jupiter appears in the evening sky this month.  It is well up in the eastern sky at sunset gleaming brightly  in front of the stars of  Taurus.  It continues to retrograde (move west compared the starry background) for most of the month.

On January 30, Jupiter stops retrograding and resumes its direct motion.  The numbers (1, 10, 30) in the diagram above refer to the dates in January.

On January 21, the moon appears near Jupiter.  Look in the eastern sky at 7 p.m. when the pair are placed high in the eastern sky, although they can be seen together anytime on the night of January 21/22.

Mars continues to hide in evening twilight in the western sky during January as indicated from the image made on December 13, 2012. On January 13, a waxing crescent moon is a guide to Mars. With binoculars locate the moon; Mars appears below the thin crescent near the horizon.  Mars continues to move eastward compared to the stars, although the separation from the sun decreases during the month from 23 degrees on New Year’s Day to 17 degrees at month’s end.  Mars moves deeper into evening twilight until it passes behind the sun (conjunction) on April 18.

Mercury hides within the sun’s glow during the month and moves into the evening sky late in the month, although it is only about 10 degrees east of the sun at month’s end.  Mercury appears with Mars in February.

Morning Sky

Brilliant Venus rapidly moves into bright morning twilight.  On New Year’s Day, Venus rises about 90 minutes before the sun. By month’s end it rises about 40 minutes before the sun.

On January 10, a waning crescent moon appears about 2 degrees to the left of Venus in an impressive view during morning twilight.

On January 17, Venus completes one orbit since it passed between the Earth and sun that caused the Transit of Venus observed on June 5, 2012, and started Venus’ current morning appearance.

Saturn rises in the eastern sky during early morning hours and it is well-placed in the southern skies as morning twilight begins.  Saturn appears about 16 degrees to the lower left of the star Spica.  Early in the month, the moon moves through this part of the sky.  The chart above shows the positions of Saturn, Spica and the moon on the mornings of January 5-7 at 6 a.m. CST.

Solar System

This chart shows the positions of the planets on January 15, 2013.  (Click the image to see it larger.)  Saturn and Venus are on the morning side of the solar system.  Mars and Jupiter are on the evening side with Mercury nearly behind the sun, making it in our sky during daytime.

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