April provides lengthening daylight and a continued dazzling display of Venus in the western sky after sunset. During the month daylight increases by an hour to nearly 14 daylight hours by month’s end in the Chicago area.
Mercury is a morning object throughout the month. From the northern mid-latitudes it lies low in the eastern sky during predawn hours. The moon is nearby on the mornings of April 18 and 19. On the first date, locate the moon, then use binoculars to find Mercury.
Throughout the month, Venus continues its brilliant display in the western sky. The chart above shows the length of time between sunset and Venus setting. During the first several days of the month, Venus sets nearly seven hours after sunset. From that point until mid-May, when it disappears into the sun’s glare, it rapidly sets earlier each night. Venus is quickly catching Earth and will pass between Earth and the sun in early June. Venus reaches it greatest brilliance on April 30. At this time, Venus is 12 times brighter than Jupiter.
A planet’s brightness depends on its distance, its reflectivity and its phase. (Planets display phases similar to the moon. Mercury and Venus display crescent phases, but the other planets do not.) The chart above shows the inner solar system and the proximity of Venus and Earth when Venus is at its greatest brilliance on April 30. In this view, the planets move counterclockwise.
Early in the month, Venus appears to pass the Pleaides star cluster. In a dark sky the Pleiades are visible to the unaided eye. For those readers who live in areas with many lights, use binoculars to locate the planet and the star cluster on the evenings of April 2-4. The grouping can be photographed. Use the manual setting on a camera with the aperture setting the widest setting (lowest number). On a tripod, make a 30 second exposure. Venus and the stars will appear on the processed image.
The moon returns to the evening sky late in the month as Venus is at its greatest brilliancy. On the evening of April 24, the moon appears between Venus and Aldebaran, the brightest star in Taurus.
Mars is high in the eastern sky at sunset. The chart above shows Mars, the star Regulus, and the moon at 8:45 p.m. CDT. As our planet rotates during the night, Mars appears farther to the west during the night as it sets in the west during predawn hours.
During the month Jupiter rapidly disappears into the sun’s glare. The chart above shows Jupiter at 8:10 p.m. CDT on April 15. Notice the great separation between Venus and Jupiter on this date. Jupiter goes behind the sun (conjunction) on May 13 and reappears in the morning sky later in June.
Saturn reaches opposition on April 15, entering the sky at sunset. (At opposition the sun and planet are on opposite sides of the sky as the earth passes between the planet and the sun.) When a planet is at opposition, it rises at sunset, appears in the south at midnight, and sets in the west at sunrise. The chart above shows Saturn, the star Spica, and the moon on April 6, 2012 at 10 p.m. CDT.
Even though Saturn is larger than Venus and Earth, its great distance diminishes its brightness. Venus is nearly 100 times brighter than Saturn during the month of April.
This chart shows the positions of the planets visible without a telescope or binocular on April 15, 2012. (Click the chart to see a larger image.) Notice that Earth is between the sun and Saturn (opposition). Venus is about to move between the Earth and Sun.
After the closest pairing of Jupiter and Venus, the moon appears in the western sky with them during the next several days. Here’s what to look for at approximately 8:15 p.m. CDT in Chicago:
March 24: The waxing crescent moon appears below Jupiter and Venus, near the western horizon. March 25: Jupiter and the moon are paired nicely, with the moon appearing slightly higher and to the right of Jupiter March 26: Tonight, Venus and the moon are nicely paired with both objects appearing about the same height above the western horizon. This is the night to catch a classic photographic view of the moon and Venus together. Use a variety of automatic settings on your digital camera. If the camera has a manual exposure setting, set it for 4 seconds with the aperture at its lowest setting (number). March 27: The moon stands above Venus and Jupiter as the planetary pair continues to separate.
This 2-second photo was made at 8 p.m. CDT on March 25, 2012. After a promising early twilight, the clouds moved in.
After missing the best evening (March 26), Venus with the moon, because of mostly cloudy skies where the sky was clear in patches at varying intervals, the skies were hazy on March 27 in the Chicago area. This two-second time exposure was made at 8:10 p.m. CDT shows Venus, Jupiter, the moon, and Aldebaran.
Full Moon — 3/8
Last Quarter — 3/14
New Moon — 3/22
First Quarter — 3/30
Daylight Saving Time begins for most states in the U.S. on March 11 at 2 a.m. local time. Advance clocks 1 hour.
The Vernal Equinox occurs on March 20 at 12:14 a.m. CDT, signalling the beginning of Spring. Daylight increases for three months until late June. At this time, the sun appears directly above the equator, meaning that individuals living at the equator have the sun appear directly overhead. The sun does not appear directly overhead from the Chicago area.
The month opens with the spectacular Venus-Jupiter gathering in the western sky, just after sunset. With binoculars and a clear horizon, locate Mercury low in the sky early in the month.
By mid-month, Jupiter and Venus appear close together. While millions of miles apart, the two planets appear about 3 degrees (six full moons) apart. The chart above shows the pair on March 12, one of the nights they appear closest. Notice the view is one hour later as daylight saving time (advance your clock one hour) on March 11.
The animation above shows Venus and Jupiter each night during March 2012 in the early evening sky. Watch to two planets appear to converge then separate.
After the closest pairing of Jupiter and Venus, the moon appears in the western sky with them in late March. Here’s what to look for at approximately 8:15 CDT in Chicago:
March 24: The waxing crescent moon appears below Jupiter and Venus, near the western horizon.
March 25: Jupiter and the moon are paired nicely, with the moon appearing slightly higher and to the right of Jupiter
March 26: Tonight, Venus and the moon are nicely paired with both objects appearing about the same height above the western horizon. This is the night to catch a classic photographic view of the moon and Venus together.
March 27: The moon stands above Venus and Jupiter as the planetary pair continues to separate.
At the same time that the brilliant group gleams in the western sky, Mars lies low in the eastern sky. It is the brightest starlike object in this part of the sky, but it dramatically under shines the bright duo in the west. Mars appears slightly red-orange and its color can be distinguished with binoculars. On March 3,Earth passes between the sun and Mars — an opposition. At this time, Mars is about 60 million miles away. An opposition for Mars occurs about every 25 months. Because Mars’ orbit is moderately elliptical, this opposition occurs when Mars is farthest from the sun (aphelion), it is not as close or as bright as several previous oppositions.
The waxing gibbous moon appears near Mars on March 6 and March 7.
A few days later, the Moon appears near Saturn and Spica. Saturn rises just around midnight in the southeastern sky. The chart above shows the planet-star pair with the moon for March 10 and March 11. The constellation Corvus is nearby.
The chart above shows the planets at mid_March 2012. Notice that an imaginary line extended from Earth to Venus goes to Jupiter. That is why the two planets appear close together in our sky, but they are widely separated in space. Additionally notice that our planet is between Mars and the sun — they are on opposite sides of Earth.
There’s a bright “you shouldn’t miss this” event occuring during the late February, 2012. The objects are so bright that casual sky watchers can view this grouping of planets and the moon without a telescope or binoculars. During the next few evenings, look for the moon, Venus, and Jupiter in the western sky, just after sunset. The chart above shows the western sky at about 6:45 p.m. in the Chicago area. Venus is the brightest starlike object in the evening sky. Jupiter, a little dimmer than Venus, stands (east) above and to the left (south) of Venus. Here are the events to watch:
February 24: The waxing crescent moon appears below (west) and to the right (north) of Venus.
February 25: In one day the moon moves so that it appears to the upper right of Venus. During these evenings the nighttime side of the moon is illuminated by sunlight reflected from our planet, as the image above shows. This gently illuminates the night portion of the moon in a similar effect to when a full moon illuminates the ground here. From the moon, the earth’s phase is just past full.
February 26: The moon appears higher and to Jupiter’s lower right.
February 27: Jupiter appears beneath the moon.
During the next few weeks watch Jupiter and Venus pass in the early evening sky. More in the March 2012 sky watching update that will be published here soon.
Taurus the Bull is visible high in southern skies during January
January opens with a sky full of stars and planets in the evening sky. Taurus the Bull appears high in the southern skies during January’s evening hours. Two bright star clusters, known as the Hyades and the Pleiades, help construct the constellation. The “V” shaped cluster forms the bull’s head and face, although the bright reddish star Aldebaran that forms the bull’s eye is not part of the cluster. Aldebaran is one of the largest stars in our part of the galaxy. If placed in our solar system, it would extend beyond the orbit of Mars. The Pleiades ride on the bull’s back. The Taurus region of the sky is best explored with the low power of binoculars. The stars in the clusters are so widely spread that they are best viewed with at low power.
First Quarter: January 1 & January 31
Full Moon: January 9
Last Quarter: January 16
New Moon January 23
Our planet, Earth, reaches perihelion — its closest point to the sun — on January 4 at 6 p.m. CST. At this time we are 91,401,967 miles from the sun.
Along with the bright stars, Venus and Jupiter shine brightly in the clear January skies.
Venus can be seen low in the western sky throughout the month. As the planet slowly catches up to our planet, Earth, in its orbit, it rises higher in the sky and gets brighter each evening. The moon is nearby on January 25 and 26. Only two other objects are regularly brighter than Venus: the sun and the moon. It can be easily mistaken for the bright lights on an airplane.
Jupiter shines brightly, although not at bright as Venus, from the southern skies during the early evening. Venus shines about 4 times brighter than Jupiter. The moon passes Jupiter twice this month as the charts above show, first early in the month (January 2) and then again on January 29 and 30.
Mercury opens 2012 low in the southeastern sky before dawn. The planet is difficult to locate without a good horizon and binoculars. Antares and Sabik are nearby. Mercury disappears into the bright sun’s glare during the second week of the month and is invisible until it appears in the evening sky in late February.
Mars rises in the eastern sky around midnight this month, appearing near Denebola — Leo’s tail. On January 13, its identification is easier when the moon is nearby.
A few days later, the moon is near Saturn. At 5:30 a.m. on January 16, the moon appears near the planet and Spica.
On the morning of January 19, the moon makes a nice configuration with Antares and the stars of Scorpius around 5:30 a.m.
The chart above shows the positions of the visible planets at mid January 2012. Mercury is headed for superior conjunction (behind the sun) and Mars for opposition (Earth is between Mars and the sun.) Saturn and Jupiter are nearly on opposite sides of the their planetary orbits from each other.
The Sun reaches its southern-most point in its yearly travels at 11:30 p.m. CST on December 21, signalling the beginning of winter in the northern hemisphere and the beginning of summer for southern latitudes. This is the Winter (December) Solstice.
The Moon is in total lunar eclipse on December 10, but the best parts of the eclipse are not visible from the Chicago area. The eclipse begins at 5:33 a.m. CST, when the moon enters Earth’s penumbra. The lunar darkening is largely unnoticed by most observers. At 6:45 a.m. CST, the moon enters the darker shadow where the partial eclipse begins. The moon is very low in the western sky, setting only 25 minutes later. The sky is brightening as the moon sets with sunrise. Farther west in the U.S. more of the eclipse is visible, although the full eclipse is visible from the Pacific, Australia and Asia.
A lunar eclipse occurs when the moon crosses into the earth’s shadow. The moon’s orbit is tilted slightly compared to the earth’s orbit. The moon does not cross into the shadow each month. The next total lunar eclipse visible from the Chicago region is April 15, 2014. Parts of a partial lunar eclispse are visible June 4, 2012.
First Quarter — 12/2
Full Moon — 12/10
Last Quarter — 12/18
New Moon — 12/24
Mercury moves rapidly past Earth (inferior conjunction) on December 4 and into the morning sky. During the last half of the month it makes an appearance low in the eastern sky somewhat near the star Antares. The chart above shows Mercury, the moon, and Antares at 6:30 a.m. on December 22. Find a place with a clear view of the horizon to see the widely spaced trio. Binoculars will help locate Mercury and Antares.
Venus is the bright “star” in the southwest, just after sunset. Its brilliance can be easily confused for an airplane. Late in the month, the moon appears near Venus as displayed on the chart above.
Mars is a reddish “star” that rises around 10:30 p.m. during this month. It is near the stars of Leo (Denebola and Regulus). On December 16 and 17, the moon is nearby and is identified on the chart above in the southern skies at 5 a.m.
As the sky darkens each evening with Venus in the west, bright Jupiter is in the eastern sky. Jupiter rises during the daytime and is high in the southeast by 8 p.m. The chart above shows Jupiter and the moon for December 5 and 6. Jupiter appears to move westward as our planet rotates, setting in the western sky around 3 a.m.
Saturn rises during the predawn hours and is visible low in the southeast around 5 a.m. It is near the star Spica. The constellation Corvus is nearby. One December 19 and 20, the moon helps with the identification of Saturn and Spica.
Viewing the morning sky, three planets (Mercury, Saturn, and Mars) line up across the sky in late December. At 6:40 a.m., Mercury is low in the east, Saturn is in the south, and Mars is higher in the southwest. The chart above shows the three planets at this time.
Viewing the solar system from above, the trio described above are on the same side of the sun as Earth, appearing in the morning sky. Venus and Jupiter are in the other side appearing in the evening sky.
As the daylight continues to shrink, the bright winter sky appears earlier and stays longer, giving observers an opportunity for some skywatching.
The immense Andromeda galaxy, also known as Messier 31 or simply M31, is captured in full in this new image from NASA’s Wide-field Infrared Survey Explorer, or WISE. The mosaic covers an area equivalent to more than 100 full moons, or five degrees across the sky. WISE used all four of its infrared detectors to capture this picture (3.4- and 4.6-micron light is colored blue; 12-micron light is green; and 22-micron light is red). Blue highlights mature stars, while yellow and red show dust heated by newborn, massive stars. More details.
November evening skies are a transition between the bright stars that dominate summer and winter skies. Our summer view of the Milky Way is shifted towards the west and the winter section appears in the eastern sky later in the night. This permits views of celestial wonders beyond the bounds of our home galaxy. The magnificent Andromeda Galaxy,also known as M31, is nearly overhead throughout the month. Binoculars will reveal a fuzzy patch of light. The photo above shows a satellite view of the galaxy revealing stars of varying ages.
As for the planets visible this month from the Chicago area and across the globe at northern mid-latitudes, Mercury and Venus are low in the southwest during evening twilight. The accompanying video shows their positions each evening for the month. The video repeats twice. To locate this pair, find a location with a clear horizon. With binoculars locate them in the southwest sky. Mercury moves very quickly. It is visible near Venus for most of the month then disappears into the sun’s glare.
At month’s end Venus appears near a crescent moon on November 26.
Daylight Saving Time ends 2 a.m. Central Time for the time zone on November 6. During the month we lose another hour of daylight as the sun appears farther to the south.
A solar eclipse occurs on November 25, but it is visible from the southern hemisphere (South Africa, Antarctica, Tasmania, and New Zealand).
Mars is a morning planet that is visible high in the southeast before sunrise.
Early in the month, Mars appears to pass Regulus. Watch Mars’ rapid eastward motion compared to Regulus by looking each clear morning. They appear closest on the morning of November 10.
About a week later, the moon appears near Mars and Regulus. In the diagrams above, notice how far Mars has moved past Regulus, since their closest appearance.
Jupiter appears in the east at sunset. It is brighter than all celestial objects in its vicinity, except when the moon appears nearby on the evenings of November 8 and 9. The planet is in the south around midnight and in the west during morning twilight.
Saturn rises in the east before sunrise, appearing near Spica. The moon is nearby on November 22.
The planets’ positions in their orbits are shown for mid-November 2011.
Look for the Big Dipper low in the northwest sky during early evenings in early autumn
As the weather changes into the cooler evenings of autumn, the stars slowly transition toward the bright winter stars. One familiar group, known as the Big Dipper in North America, lies low in the northwestern sky during the early evening hours of October. More, formally known as the Great Bear (Ursa Major), the stars can be found in the northern sky throughout the year. In autumn they start the evening low in the northern sky; they are likely blocked by the trees or the neighbor’s house.
An interesting pair of stars, Mizar and Alcor, is at the bend of the dipper’s handle. Mizar is the brighter star with dimmer Alcor nearby. If you cannot see the close pair, use binocular. While not physically connected in a binary star system, their close proximity makes them appear together. Mizar is about 100 light years away with Alcor perhaps another light year away from its brighter neighbor.
This chart shows the positions for the visible planets as seen from north of the solar system. Notice that Earth is between Jupiter and the sun. Venus, Mercury, and Saturn appear near the sun. Earth is slowly moving up to catch Mars.
Look in the west for Venus, Mercury and the moon just after sunset on October 28.
Always difficult to locate, Mercury appears near Venus in late October. As the sky darkens on October 28, look for the moon and the reddish star Antares. Look farther to the right of the moon for bright Venus and below it for Mercury. You’ll need a good horizon. Binoculars will help locate Mercury.
Venus is slowly emerging from behind the sun. Early in October, Venus sets about 50 minutes after the sun. Venus sets later than the sun throughout the month, ending the month setting about 90 minutes behind the sun. The chart from last month’s night sky description shows the difference of times between sunset and Venus set.
Mars is a morning star rising after 1 a.m. throughout the month. Early in the month, it appears near the Beehive Cluster. (See the separate article about this event.) The moon serves as a good guide to Mars on October 21 and 22 as displayed in the chart above. The star Regulus serves as a marker of the sun’s annual path and the plane of the solar system. Look for Mars each morning and note how its orbital motion is carrying it closer to Regulus. Of course, the two are not close; Regulus is much farther away than Mars. Mars will appear to pass Regulus next month.
Jupiter is the “bright star” in the eastern sky during the early evening hours. Jupiter is at opposition and closest to Earth on October 29. At this time the sun and Jupiter are on opposite sides of our planet. Jupiter will rise in the east at sunset, be south around midnight and set in the west around sunrise. It’ll be in the sky all night. On October 12 and 13, the moon makes a nice grouping with Jupiter and the star Hamal.
Saturn appears near Spica at month’s end in the east before sunrise.
Saturn is not visible for most of the month. It is at conjunction on October 13. At this time, the sun is directly between Saturn and our planet, so that Saturn is in the sky during the daytime. Look at the planet orbit diagram above to see Saturn’s location compared to our planet. By the end of the month, Saturn rises into the eastern sky, just before sunrise. On Halloween, Saturn appears near Spica. As for most observations that occur during twilight, use binoculars to see the pair.
Please share your observations in the comments section or ask any questions that can be answered in future articles.
The bright stars of the Summer Triangle shine from high in the southern skies during the evenings in September. Three bright stars — Vega, Deneb, and Altair — that are actually part of the their own constellations, mark the “corners” of the triangle. Deneb is one of the brightest stars in the sky. Shining with the brightness of 170,000 suns, this star is 2,500 light years away. The combination of actual brightness and distance makes it the 19th brightest star seen in the sky at night. Compared to its neighbor, Vega appears as the 5th brightest star, although it is only 60 times brighter than our sun and 25 light years distant. The third star, Altair, ranks as the 12 brightest star with an actual brightness of about 11 suns with a distance of 17 light years. The brightness that a star appears in our sky is related to the star’s actual brightness and distance.
Deneb is part of the constellation Cygnus, the swan. It represents its tail. The head of the swan is marked by Albireo. Look at this star through a small telescope. It will reveal a wonderful double star, one golden, one blue.
Albireo, as seen through a small telescope, is two stars. One is gold, the other blue.
On September 3, the moon appears near the bright star Delta Scorpii as seen from mid-latitudes. The moon can been seen covering the star from the southeastern US. This link provides more details. For others, the moon appears very close to the star with the bright star Antares nearby.
The Autumnal Equinox occurs at 4:05 a.m. CDT on September 23. At this time, the sun is directly above the earth’s equator. On this date at noon the sun will go directly overhead for people living at the equator. For residents of mid-latitudes, the sun will about halfway up in the south at noon, rising at the east direction point and setting at the west cardinal direction. The equinox also brings equal daylight and darkness at 12 hours each. From this date until the Vernal Equinox in March, the length of nighttime is longer than daylight hours.
Mercury is usually difficult to see as it rapidly shuttles from morning sky to evening sky. During early September, Mercury makes a brief appearance in the morning sky. The chart above shows Mercury and Regulus, the bright star in Leo, at 6 a.m. on September 9. Locate an observing spot with a clear horizon. Looking with binoculars locate Mercury and Regulus in a close pairing.
Venus begins its evening appearance late in the month. Venus passed behind the sun in mid-August. Venus and Earth are like two cars on a race track; Earth is in an outside lane and Venus an inside lane. Along with a shorter course, Venus moves faster than Earth. In September, Venus is nearly on the other side of the track and the infield spectators (the sun) are blocking our view of the planet. It will move faster and catch up to our planet and move between us in the sun (inferior conjunction) in June 2012.
As the chart above indicates, the sunset time between Venus and sun will be between about 30 minutes and 45 minutes throughout September. Sharp observers may note it very close to the horizon in the west after sunset. Binoculars will be helpful. As Venus begins to catch up to Earth, it will appear longer and longer in the western evening sky, outshining all other objects in the night sky besides the moon. It can be easily mistaken for lights on an airplane.
As Venus closes in on Earth, it will grow brighter until April 30. The greatest separation (marked greatest elongation on the diagram) between Venus and the sun is March 27, 2012, with Venus setting nearly 7 hours after the sun. It’ll be a spectacular sight in the spring night sky, when the tilt of the solar system provides marvelous views of the inner solar system. Venus will make interesting viewing as it passes bright stars and other planets during its evening appearance. We will note them here in future postings.
Mars and the moon, September 2011
Marsis visible in the eastern, predawn sky. Late in the month, the moon appears near Mars. The chart above shows Mars with the moon and bright distant stars (Pollux, Castor, and Procyon) on September 22 and 23. During September, Mars shines nearly equal to the bright stars in its background. While distinctly reddish-orange, the moon helps identify it late in the month.
Jupiter shines brightly from the eastern sky during late evenings as it rises in the east around 10 p.m. early in the month. It is in the sky until sunrise and it dominates the southern sky just before sunrise. Late in the month, it rises in the east around 9 p.m. The chart above shows the moon and Jupiter on September 15 and September 16. The bright star Hamal is nearby.
Saturn disappears into the sun’s bright sunlight as it moves behind the sun in October.
We’d appreciate reading what you are observing. Please post any interesting observations in the comments section.