Venus and the Moon Tonight, April 21, 2015


Brilliant Venus is joined by the crescent moon this evening in the western sky.  In the image above, the moon is overexposed in this 10-second exposure.  Tonight the moon is 4 degrees to the upper left of the star Aldebaran and nearly 8 degrees from Venus.


In this close-up view of the same scene in a two-second exposure, the moon’s crescent is distinct along with a soft glow from the lunar night portion.  This effect is known as “earthshine.”  Sunlight reflected from Earth, which is just past the full phase as seen from the moon, gently illuminates the night portion of the moon, similar to the manner in which a full moon illuminates the terrestrial landscape.

Venus & Jupiter, April 2015

Venus and Jupiter gleam from the evening sky during April 2015.  Venus is the bright celestial gem that sparkles in the western sky after sunset.  It sets over three hours after the sun, making it easily observed.  The difference between sunset and the planet setting grows to nearly 3 hours, 40 minutes after sunset by months end, allowing Venus to around midnight.


Early in the month, Venus appears nearly 19 degrees to the upper left Mars, fading in brightness and moving into the sun’s bright glare. As the month progresses, Venus moves higher in the sky as the stars appear lower in the west each night at the same time.  Watch Venus approach and move between the Pleiades star cluster and the star Aldebaran near mid-month.  Early in the month. Venus is about 10 degrees below the Pleiades and 20 degrees to the lower right of Aldebaran.


Meanwhile, Jupiter, shines from the southeastern sky near the star Regulus, 80 degrees from Venus.  By late June, Jupiter and Venus appear very close together in the western sky just after sunset.


During the second week of the month, Venus passes the Pleiades.  On the evenings of April 10 and April 11, Venus appears about 2.5 degrees to the left of the cluster.  Look through binoculars to capture a captivating view of the brilliant planet and the star cluster.


Venus appears to move between the Pleiades and Aldebaran on April 13, with the star about 10 degrees from Venus.


Late in the month, the moon joins the grouping.  On April 20 the moon appears to the lower left of the Pleiades.  On April 21, the moon appears about 4 degrees to the upper left of Aldebaran.


The moon moves farther east each night and reaches Jupiter on April 26, appearing nearly 8 degrees from this giant planet.

By month’s end Venus and Jupiter at about 50  degrees apart and two months from a spectacular conjunction in the western sky.

Sun and Moon, April 2015

The Sun


The length of daylight grows nearly 90 minutes during April.  By month’s end, the sun is in the sky for almost 14 hours in the Chicago area.  Now rising north of east and setting north of west, the sun’s daily arc across the sky grows longer each day with about 3 minutes added each day.  The blue area on the chart above shows the daylight during the month compared to the bell-shaped curve that indicates the length of daylight for the entire year.

The Moon

NASA Photo

NASA Photo

Phase Date/Time Moonrise Moonset
Full Moon 04/04/15 (7:06 a.m.) 6:46 p.m. (04/03) 6:34 a.m.
Last Quarter 04/12/15 (10:44 p.m.) 2:11 a.m. 12:35 p.m.
New Moon 04/18/15 (11:57 a.m.) 6:07 a.m. 7:42 p.m.
First Quarter 04/25/15 (6:55 p.m.) 11:54 a.m. 2:05 a.m. (04/26)
Times are Central Daylight Time for Chicago, Illinois, from US Naval Observatory calculations. (For mjb)

Lunar Eclipse


Photo:  National Geographic

On the morning of April 4, there is a lunar eclipse, part of which is visible from the Chicago area.  The moon sets before the full eclipse occurs.  Here are the events of April 4 for Chicago:

  • April 3, 2015:  The moon rises at 6:46 p.m. CDT
  • During the night as the earth rotates the moon rises higher in the sky and then begins to descend in the west.
  • April 4, 2015:  At 4;01 .m. CDT, the moon begins to move into the outer layer of the shadow.  The moon starts its “penumbral” eclipse phase.  For most observers, they cannot see much darkening.
  • April 4, 2015:  5:15 a.m.  The moon is now low in the west, less than two hours from setting, and the best part of the eclipse begins.  As the eclipse proceeds, the moon moves into the earth’s shadow and begins to darken, and the sky begins to darken because of the approaching sunrise.  Approximately 50% of the moon is immersed in the shadow and eclipsed as the sky brightens and the moon descends toward the horizon.
  • April 4, 2015:  6:58 a.m. CDT.  The moon sets as seen from the Chicago area.

For locations farther west, more eclipse is seen.  Observers California, Oregon and Washington can see the entire eclipse.

The Griffith Observatory’s (Los Angeles) link to a life stream of the eclipse beginning at 4 a.m. CDT:

Venus and Moon, March 21 & 22, 2015


Brilliant Venus and the moon appeared near each other during the past two evenings.  On March 21, the crescent moon appeared about 12 degrees below the planet.  Notice that the night portion of the moon is illuminated.  Sunlight reflected from our planet gently illuminated the lunar night.  From the moon, Earth appeared nearly full.  In the same way the full moon illuminates terrestrial features when it is full, our planet illuminates the night portion of the moon when the moon appears near the crescent phases.  This effect is known as “Earthshine.”


On the next evening the moon appeared about 4 degrees to the left of Venus.  In the overexposed image, notice the Earthshine.

More information about the evening appearance of Venus:

Venus as an Evening Star

Venus and Jupiter, March 17, 2015


Brilliant Venus shines in the western sky this evening.  It shines all other visible celestial objects this evening.  During late March is sets nearly three hours after sunset, appearing as a sparkling celestial gem in the western sky.   On Sunday, March 22, the moon appears about 3.5 degrees to the left  of Venus.  Look for the pair as the sky darkens.


Meanwhile, bright Jupiter shines high in the southeastern sky this evening near the star Regulus.  Tonight Jupiter is nearly 17 degrees to the upper right of Regulus.

Venus and Mars, March 2015

Brilliant Venus and Mars shine from the western evening skies during March, just after their spectacular conjunction last month. Venus is the brightest celestial object after the sun and moon.  During March, Venus climbs higher in the sky.  By month’s end it sets over three hours after the sun.  It also appears farther north each evening.


On March 1, Venus appears 3.5 degrees to the upper left of Mars.


At mid-month, Venus appears higher in the sky and Mars is heading toward the sun’s glare.  They are separated by 10 degrees.


Through a telescope at 100 power, Venus shows a distinct phase as shown above.


A few nights after new moon the waxing crescent moon joins Venus.  The pair is separated by 3.5 degrees with Mars 13 degrees to the lower  right of Venus.


By month’s end, Venus appears high in the western sky during the early evening, setting well after twilight ends with Mars 17 degrees below Venus.

More information about the evening appearance of Venus:

Venus as an Evening Star

Sun & Moon, March 2015


Daylight increases 1 hour, 25 minutes during the month, that’s almost 3 minutes each day.  The vernal equinox occurs at 5:45 p.m. CDT when the sun’s rays are most redirect at the equator.  After this date and until late September, the sunlight is most directed toward the northern hemisphere.  At the equinox, the length of day and night are equal.  Coincidentally, early on equinox morning, a total solar eclipse is visible across the North Atlantic.  Partial solar eclipses are seen across Europe, North Africa, and western Asia.

Daylight Saving Time begins across significant geographic regions of North America in the early morning hours of March 8.  At this time clocks are advanced one hour.  As our chart indicates above, there’s not much daylight to save and shift into the evening hours.  When the clocks are “sprung forward,” there’s only 11 hours, 35 minutes of daylight  in the Chicago area and at the same latitude.

The Moon


NASA Photo

NASA Photo


Phase Date/Time Moonrise Moonset
Full Moon 03/05/15 (12:05 p.m. CST) 5:59 p.m. CST 6:34 a.m. CST (03/06)
Last Quarter 03/13/15 (12:48 p.m.) 1:41 a.m. 11:45 a.m.
New Moon 03/20/15 (4:36 a.m.) 6:59 a.m. 7:43 p.m.
First Quarter 03/27/15 (2:43 a.m.) 12:43 p.m. 2:50 a.m. (03/28)
Times are Central Daylight Time (except as noted) for Chicago, Illinois, from US Naval Observatory calculations. (For mjb)

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