Eastern Daylight-Saving Time (EDT) starts on March 8th, and March 20th is the first day of astronomical spring, or the vernal equinox. Although not perfect, the weather becomes a lot more tolerable this month, and the days are getting longer at a rapid pace. Getting dark later seems to be an equitable trade for the better weather after February’s extreme cold temperatures.
The sky map below represents the sky as it will appear in mid-March at the end of astronomical twilight, the arrival of complete darkness, at 7:45pm EDT. The Scope Out monthly focus is on the constellations that are just to either side of the meridian, which is near the 6th hour (6h) of right ascension line in the March sky map. For a primer on how to use this sky map, please read How to begin Observing the Night Sky.
Scope Out divides the celestial sphere into three zones to aid in finding constellations:
2. Northern Constellations: Orion still catches the eye, but it is beginning to march off of the stage on the western horizon. Find March’s remaining northern constellations, Cancer, Leo, and Leo Minor near the zenith.
3. Southern Constellations: The best-placed constellations in March are Hydra, Sextans, Pyxis, and Crater. Some of these constellations, Pyxis, Hydra, and Crater in particular, are difficult to view because their extreme southern placement prevents them from rising very far above the horizon.
Mercury remains hidden all month as it makes its pass around the far side of the Sun. Venus and Mars continue share the western horizon, and can be seen about an hour after sunset. While Mars grows dimmer and is placed a little closer to the sun each evening, Venus’ brightness will dominate the western sky after sunset, and will appear a little higher above the horizon each evening. Jupiter is just past opposition, and is already well above the eastern horizon after sunset. Saturn continues to rise earlier each evening, appearing above the eastern horizon about four hours after sunset. Uranus is on the western horizon near Venus and Mars all month, and can be glimpsed with optical aid about an hour after sunset. Neptune is too near the sun to be seen this month.
THE LUNAR CALENDAR
Conjunction with Jupiter
Conjunction with Saturn
Conjunction with Mars
Conjunction with Venus
Vernal Equinox – March 20, 2015 at 22:45 UTC (18:45 EDT).
The Sun’s arrival at the zero hour of right ascension marks the vernal equinox, or beginning of astronomical spring. This is the point at which the ecliptic intersects the equator. which is why on this day the days and nights are of almost equal length. Read The Ecliptic – A Trace of the Sun’s Path across the Celestial Sphere for more information on the Sun’s movements on the ecliptic.
Conjunction of Venus and Uranus – March 4th.
This is the closest planetary conjunction of the year. Use optical aid to find Uranus about .3° below Venus. Notice the stark difference in their brightness.
© James R. Johnson, 2015