Astronomy

A Sky Full of Planets in the Morning Sky, 2015

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A recent appearance of Mars and Venus

Venus, Jupiter, Mars and Mercury appear together in the morning sky during the second half of 2015.  Brilliant Venus moves from the evening sky to the morning sky.  After the Great Epoch Conjunction with Jupiter in the summer of 2015, the planets pass again in the morning sky, yet not as close as the June conjunction.

The chart above (from US Naval Observatory data) shows the rising times of Venus, Jupiter, Mars and Mercury compared to sunrise from June 14, 2015 through November 8, 2015.

Mars passed behind the sun (superior conjunction) on June 14 and slowly climbs into the morning sky.  Its rate is much slower than the other three planets visible in the 2015 morning sky.  While Mars is near our planet, it appears to move through its orbit at about half our speed, so it takes longer periods to move through the sky.  This is indicated by the slope of the Mars rising line compared to the other planets.  Other conjunction dates:

  • Venus, August 15, 2015 (inferior conjunction.
  • Jupiter, August 26, 2015 (conjunction)
  • Mercury, September 30, 2015 (inferior conjunction)

The chart above shows the rising times of the planets compared to the sun.  When the rising lines of the planets cross, they rise at the same time indicating they are close together in the sky.  The conjunctions (closest approach as seen from the Chicago, Illinois area) occur within a day or two of these dates.  The important dates of the planet groupings:

A:  Venus and Mars, September 3, 2015
B:  Mercury at Greatest Elongation, October 16, 2015, appearing with the trio in morning sky.
C:  Jupiter and Mars, October 18, 2015
D:  Venus and Jupiter, October 25, 2015
E:  Venus and  Mars, November 3, 2015

A.  Venus and Mars, September 3, 2015

This is a widely spaced grouping shown above at 5:30 a.m. CDT.  Venus and Mars are nearly 9 degrees apart.  Venus is nearly 300 times brighter than Mars.  (Click the images to see them larger.)

A week later, the crescent moon joins Venus and Mars, appearing about 4 degrees from Venus.

During the next month, Venus moves higher in the sky and Jupiter joins the Venus and Mars.  The crescent moon moves through the region on October 8 and October 9.  On the first date the moon is 4 degrees from Venus and 5.5 degrees from Jupiter on the next morning.

 Mercury at Greatest Elongation, October 16, 2015

Mercury appears at its greatest (elongation) separation from the sun and appears far below the planetary waltz that appears higher in the sky.

C:  Jupiter and Mars, October 18, 2015

Jupiter and Mars are less than a half degree apart. Jupiter is 25 times brighter than Mars.

D:  Venus and Jupiter, October 25, 2015

While not an Epoch Conjunction, Venus and Jupiter are just over 1 degree apart (not an Epoch Conjunction) with Mars to their lower left.  The next Venus-Jupiter conjunction is August 27, 2016, when the planets are less than 1 degree apart, only slightly closer than this conjunction.

E:  Venus and  Mars, November 3, 2015

In this second pairing, Mars and Venus are very close, about 3/4 degree apart.  Venus still overwhelms Mars in brightness.

The next few months promise a sky full of planets.  Take a look.

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