March 2018 Skygazing from the Robert Ferguson Observatory Featured

Mars, Jupiter and Saturn decorate the morning sky, and Venus is joined by Mercury in the evening sky. This is the best evening apparition of Mercury in 2018. And we have another chance this month to view the Zodiacal Light in the west. Jupiter is becoming very dominant and well worth observing in the a.m. hours as it approaches opposition.


[Note: All times are local Pacific Time and calculated for the RFO website.]

* Use the "What's Up in the Night Sky" link on RFO website for additional events and details.

Moon - The "Worm" full moon is on the evening of 3/1. The moon is near Jupiter around 12:30 am on the morning of 3/7. Last Quarter is on the morning of 3/9. The moon is near Saturn around 5 am on 3/11. New Moon is on the morning of 3/17. A thin 2.7% crescent moon 8° high in the west 40 minutes after sunset (or at 8:00 pm calculated for the RFO site) on 3/18 with Venus and Mercury in a line to the north. The moon is near the bright red-orange star Aldebaran around 8:30 pm on 3/22. First Quarter is on the morning of 3/24. The moon is near the bright blue star Regulus around 4 am on 3/28. Finally, there is a "blue" full moon on the morning of 3/31.

Mercury - Mercury has its best evening apparition of the year this month from about 3/4 to 3/23, reaching a maximum altitude of nearly 9° 45 minutes after sunset on 3/15, which is also greatest elongation east. As always, Mercury is brightest early in this period and will fade quickly toward the end of the period. Mercury will be VERY close to brighter Venus on the evening of 3/5. A thin crescent moon lines up with these two on the evening of 3/18 (see above).

Venus - Venus is now emerging into the evening sky, staying low at first but will become more prominent during the month. It is VERY close to Mercury on the evening of 3/5 and is between the crescent moon and Mercury on the evening of 3/18.

Mars - Mars moves from Ophiuchus to Sagittarius on 3/11 and rises around 3 am (DST) mid-month. It draws closer to Saturn throughout the month, the two coming very close together by month-end.

Jupiter - Jupiter, in Libra, is near the moon around 12:30 am on 3/7 and begins retrograde motion on 3/9. Jupiter will be rising around 11pm by the end of the month. Jovian satellite events are now readily observable during the a.m. hours. Details on these are on our website(*).

Saturn - Saturn, in Sagittarius, is in the southeast morning sky, rising around 3:30 am (DST) mid-month. The moon is near Saturn around 5am on 3/11. Saturn is approaching Mars, with the two coming very close together by month-end.

Zodiacal Light - A few times each year, we get a chance to see a very interesting phenomenon: the "Zodiacal Light". This is a faint glow in the sky caused by sunlight reflecting off dust and debris in the plane of our solar system. For about two weeks during this month the Zodiacal Light will be viewable in the west after twilight. You will need a good, dark (no light pollution!), clear western sky to observe this. If you have a planisphere or star chart that shows the line of the Ecliptic, this is where you should see the glow. It will be broadest near the horizon and taper gradually in a long tall triangle as it rises into the sky, losing itself in the glow of the Milky Way, which it intersects. The base of the triangle will be in Pisces, south of the Great Square of Pegasus. It will rise through Aries toward the Pleiades and the bright red-orange star Aldebaran, continuing on toward Gemini. If you are in a sufficiently dark location and realize what you are seeing, it is unmistakable. The dates for looking this month are 3/5 to 3/18. Start viewing at about 7:40pm until about 8:20pm (an hour later in PDT).

Algol Eclipses - The sky position and long nights of fall and winter make this the best time to observe the famous eclipsing variable star Algol (beta Persei) in Perseus. The orbital plane of this close pair of stars coincides with our line of sight. Once every orbit the dimmer star eclipses (actually, occults) the brighter star and the light we see from what appears to us as a single star grows dimmer. This happens every 2 days 48 minutes 56 seconds. The eclipse lasts about 10 hours, though the most obvious dimming lasts about 6 hours, centered around the eclipse minimum. Normally, Algol is at magnitude 2.1 (similar in brightness to the North Star) but dips to magnitude 3.4 at eclipse minimum. Algol is in a trapezoid arrangement with 3 other stars: pi, rho and omega Persei. Most of the time Algol is much brighter than the other 3 stars. However at eclipse minimum it is the same brightness as rho Persei, the star diagonally opposite Algol in the trapezoid. Use binoculars to help observe these 4 stars easily. The nearby star gamma Andromedae, at magnitude 2.2, can be used as a reference for Algol at its normal brightness. Convenient eclipse minimum times are listed below. Those in early evening allow for watching Algol return to normal brightness after minimum. Those in morning hours allow watching Algol dim before minimum.

Algol minima:

3/11 4:48 am

3/14 1:37 am

3/16 10:26 pm

3/19 7:15 pm

Daylight Saving Time - DST begins at 2am on 3/11.

Vernal Equinox - The equinox occurs at 9:15am on 3/20.


Capitalized items refer to the sections above.

3/01 - "Worm" Full MOON

3/04 to 3/23 - MERCURY in the west

3/05 to 3/18 - ZODIACAL LIGHT in the west

3/07 - MOON near JUPITER

3/09 - JUPITER begins retrograde motion

3/09 - Last Quarter MOON


3/11 - ALGOL ECLIPSE minimum

3/11 - MOON near SATURN

3/14 - ALGOL ECLIPSE minimum

3/16 - ALGOL ECLIPSE minimum

3/17 - New MOON

3/18 - 2.7% Crescent MOON near VENUS and MERCURY in west

3/19 - ALGOL ECLIPSE minimum


3/22 - MOON near Aldebaran

3/24 - First Quarter MOON

3/28 - MOON near Regulus

3/31 - "Blue" MOON

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