2017, January 7: Venus and Mars


Venus gleams brilliantly this evening in the southwestern sky, as seen from the Chicago area. Dimmer Mars is 10 degrees to the upper left of Venus. The planets are gradually moving towards each other in the sky, but they will not pass each other.  The pair is closest on February 3.  Watch them close the gap to about 5.5 degrees during the next few weeks.

For more information about the Venus-Mars encounters and other planet observations, see these articles:

2017, January 1: Jupiter and Spica


On this New Year’s morning, Jupiter and Spica appear in the southern sky.  Jupiter is about 4.5 degrees above Spica this morning.  Jupiter passes 3.5 degrees from Spica on January 20 for their first conjunction of Jupiter’s current appearance.

More articles about the planets and their current visibilities in 2017:

2017: January Skywatching

new-year-fireworks_1Image Credit

More articles about the planets and their current visibilities in 2017:


Happy New Year!  The length of daylight increases this month by 48 minutes.  On New Years Day, the Chicago area has 9 hours, 13 minutes of daylight with the sun rising at 7:18 a.m. CST and setting at 4:31 p.m.  By month’s end the sun sets at 5:05 p.m.  Notice either the sunrise or sunset point during the month.  It gradually moves northward along the horizon.


NASA Photo

NASA Photo

Phase Date/Time Moonrise Moonset
First Quarter 01/05/17 (1:47 p.m.) 11:38 a.m. 12:31 a.m. (01/06)
Full Moon 01/12/17 (5:34 a.m.) 4:15 p.m. 7:08 a.m. (01/12)
Last Quarter 01/19/17 (4:13 p.m.) 10:41 p.m. (01/18) 11:17 a.m.(01/19)
New Moon 01/27/17 (6:07 p.m.) 6:42 a.m. 4:58 p.m.
Times are Central Standard Time for Chicago, Illinois, from US Naval Observatory calculations.
(For mjb & afb)

Evening Planets

Brilliant Venus and the Red Planet Mars shine from the western sky during early evening hours.  Venus is nearly 100 times brighter than Mars.


Venus sets nearly 4 hours after sunset and Mars follows about an hour later.  Venus and the Moon are 4 degrees apart with Mars about 12 degrees to the upper left of Venus.   Look for the moon near this planetary pair during the first 3 days of January. During January, Venus and Mars appear to move closer together as the setting lines of the two planets begin to converge.

On January 12, Venus reaches is greatest angular separation from the sun (47 degrees) and sets 4 hours after the sun.

Venus continues to brighten throughout the month.  The clear, cold nights in the mid-northern latitudes seem to accentuate Venus’ brightness.  Its brightness increases about 30% during the month as it approaches its great brilliancy.  See this article for more about Venus and Mars  in 2017.

Morning Sky


Jupiter shines brightly from the southern sky in the predawn hours of the New Year near the star Spica.  As the month begins they are 4 degrees apart.


On January 20, Jupiter passes 3.5 degrees from Spica in its first of 3 passes (conjunctions) this year — a triple conjunction with the star.  See this article for more about Jupiter and Spica.  On the evening before this conjunction, the moon is about 3 degrees from Jupiter.

Mercury makes its best morning appearance of the year when it reaches its greatest angular separation (24 degrees) from the sun on January 19.  This planet is very elusive as it emerges from the sun’s glare to appear just before sunrise for several days.  Then it disappears back into the sun’s glare to reappear in the evening sky.  In this appearance it rises just before twilight begins, about 100 minutes before sunrise.  It appears higher in the southeastern sky sunrise approaches, but the sky is brighter.  The trick is to locate it when it is high enough to view with sky moderately dark.  This requires finding a clear horizon.


It helps if the moon or another bright planet is nearby.  On January 25, the moon appears about 6 degrees to the upper right of Mercury.  In binoculars, locate the moon,  Slightly move the binocular so that the moon appears to the upper right of the view.  Mercury appears at the lower left.

Saturn begins its appearance after its solar conjunction last month.  On January 1, Saturn rises about 90 minutes before sunrise and appears low in the southeastern sky,  It appears about 15 degrees from the star Antares.  On January 24, the moon appears 3 degrees from Saturn.

As with a new year, five planets are visible during a single night:  Venus and Mars in the evening with Jupiter, Saturn and Mercury in the morning sky.  Have a prosperous New Year!

2016, December 13: Venus and Mars

dsc03820Brilliant Venus and Mars shine from the southwestern sky this evening. They are 18.5 degrees apart.  Venus is nearly 100 times brighter than Mars.  Tonight Venus sets about 3.5 hours after the sun and Mars follows about 90 minutes later.

More articles about the planets and their current visibilities:

2016: Sidereal Signs of Winter


With the slow march of the stars to the west each evening and each season, the starry patterns form a celestial calendar.  In the northern hemisphere, winter begins on December 21 at 4:44 a.m. CST.  At this time the sun’s celestial coordinates are 18 hours of right ascension and -23.5 degrees declination.  The sun passes overhead at Tropic of Capricorn, 23.5 degrees south of the equator.  On ancient star maps, the sun appeared in front of the stars of Capricornus.  Over time the earth has pivoted from the sun’s and moon’s gravitational forces so that the astronomical solstice point appears in front of Sagittarius.  See more about this below.

The group of stars that signal the beginning of winter is the informal group known as the Winter Triangle that are made of Sirius, Procyon and Sirius.  This giant sidereal shape appears complete in the southeastern sky by 9:30 p.m. CST in late December.  Sirius, the brightest star in the night sky, is distinctly blue-white through binoculars.  It may twinkle vividly when viewed near the horizon on a clear, cold night from heat rising from your terrestrial surroundings.  Procyon — known as “Before the Dog” because it rises a little before Sirius, the Dog Star — appears farther north along the eastern horizon. Procyon is not as blue as Sirius.  The third corner of the triangle is Betelgeuse, the reddish star at the shoulder or armpit of Orion.  Its colors are distinct through binoculars and a small telescope as well.

The change of seasons brings us a procession of new celestial signs.  The Winter Triangle and other bright stars in the eastern sky tell us that Winter is here.


The constellations are represented by multiple definitions.  The familiar stick figures made by connecting the stars is the most common fashion.  Another way is to divide the sky into patches like those on a quilt, although each is not equal in size.  The chart above shows the sun at solstice noon.  (The green line represents the sun’s apparent annual path on the sky that is caused by the earth’s revolution.  The moon and planets appear to move closely to that line, not on it but within a few degrees.  The red line at the top is the celestial equator; it is directly above our planet’s equator in the sky.  The vertical white line is the meridian, an imaginary line that starts at the southern horizon, goes through the overhead – zenith  — generally through the North Star — and to the northern horizon.)  The meridian divides the rising stars from the setting stars.  It marks the highest point a celestial object can reach during that day.  For the sun, it is noon.  When the sun is east of the meridian, that’s morning; we use the letters “a.m.” (ante meridiem) to designate that the sun is before the meridian.  When it is west of the meridian, that’s afternoon and we use the letters “p.m.” (post meridiem) to designate that the sun has past the meridian.  For me in that moment of time when the sun is south, it is neither 12 a.m. nor 12 p.m.  It is Noon.  So next time you meet somebody for lunch, great them with a “Good Noon!”

Earlier this year the Internet’s heart fluttered when a NASA expert stated there were 13 “signs” (for example see) in the zodiac.  This is not news.   The zodiac is the constellations that form the background for the real and apparent movement of the sun, moon and planets.  Notice on the chart above that the ecliptic, the plane of our solar system, goes through Ophiuchus, the Snake Handler, which may have been a predecessor to the modern physician.  The time that the sun spends in front of the stars of Ophiuchus is longer than the time in Scorpius.  This is the constellation that made the Internet’s heart skip a beat.  And there are occasions when the moon moves through part of Orion.  So there are 14 constellations that form the zodiac.  It’s not news, though.

Have a happy holiday season.  For me, it’s Christmas, so I wish you “A Merry Christmas” and a “Joyous New Year.”  For my readers south of the equator, it’s summer.  Have a great time at the beach!

2016: November 30, Venus and Mars


As November closes, Venus shines brightly from the southwestern sky during early evening hours.  It now sets about 2.5 hours after the sun.  Mars is 24 degrees to the upper left of Venus.  See the links to the accompanying articles for more about observing the planets.

2016, November 9: Venus


Venus shines brightly from the southwestern sky during evening twilight today as seen from the Chicago area. During the next 10 days, its setting point is the farthest south during this appearance.