Several classic planets will become the protagonists of the starry sky theater in March. Among them, the rarely seen Mercury will welcome a Greatest Eastern Elongation with excellent observation conditions. By late March, Saturn will be visible almost all night. As its setting time gradually moves earlier, the observation conditions for Jupiter are worsening. Venus, acting as the morning star, is also seeing its rising time delayed, making it increasingly difficult for us to observe.
Astronomical Overview
01st 11:40 Venus conjunction Moon: 1.7^\circ S
11th 12:35 Moon conjunction Pleiades (M45): 1.8^\circ N
16th 04:16 Mercury conjunction Jupiter: 2^\circ N
21st 07:21 Vernal Equinox
21st 19:00 Moon conjunction Spica: 2.5^\circ N
21st 19:54 Uranus conjunction Sun
23rd 08:59 Mercury Greatest Elongation: 18.6^\circ E
31st 21:25 Venus conjunction Moon: 6.6^\circ S
Moon Dynamics
05th 04:46 New Moon
13th 07:45 First Quarter Moon
20th 02:10 Full Moon
26th 20:07 Last Quarter Moon
March 15: Peak of the \gamma-Normids Meteor Shower
Meteor showers occur when Earth encounters dust clouds shed by comets while orbiting the Sun. When these dust particles enter Earth’s atmosphere, the friction causes them to burn and emit light, forming meteors. Although the actual paths of the meteors are parallel, due to perspective effects, they appear to radiate from a single point to us. There are many comets orbiting the Sun, and some provide us with more than one meteor shower; thus, there are thousands of meteor showers every year. Of course, the vast majority of them have very low rates. The \gamma-Normids meteor shower introduced here is one of them.
According to data analysis from the International Meteor Organization (IMO) from 1988 to 2007, the Zenithal Hourly Rate (ZHR) of the \gamma-Normids at its peak is about 6, and it remains below 3 at other times. As a young meteor stream, observational data is relatively limited, and both the peak time and flow rate are subject to uncertainty. According to forecasts, the active period of the \gamma-Normids in 2011 is from February 25 to March 22, with the peak likely occurring on March 15. For southern regions of China, the radiant point will rise around midnight. On the 15th, which is the 11th day of the lunar calendar, the waxing gibbous moon will set around 1:00 AM, after which observations can be conducted without moonlight interference. Since the altitude of the radiant point directly affects the number of meteors visible, observation conditions are better the further south one is in China. Taking the Guangzhou area near the Tropic of Cancer as an example, the radiant point reaches its culmination around 5:00 AM on the 15th with an altitude of 17^\circ, making observation conditions acceptable.
The meteor velocity of the \gamma-Normids is 56 km/s, classifying them as fast meteors. Interested enthusiasts can perform standard visual observations and report the results to the International Meteor Organization. Every observation report for the \gamma-Normids is very precious and important.
March 17: Mercury Conjunction Jupiter
Planetary conjunctions are not rare astronomical phenomena, but when two bright planets are at a very close angular distance, they attract significant public attention. The Venus-Jupiter conjunction on December 1, 2008, is a prime example.
Mercury and Jupiter will have two conjunctions this year; the first occurs on March 17, and the second on May 11. For this March conjunction, although it is still 6 days before Mercury’s Greatest Eastern Elongation, Mercury’s altitude at sunset will already be above 15^\circ with a magnitude of -0.8. It should not be too difficult to find it alongside the -2.0 magnitude Jupiter in the twilight.
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March 23: Mercury Greatest Eastern Elongation
The second greatest elongation of Mercury in 2011 is the Eastern Elongation occurring on March 23. This is also the second good opportunity of the year to observe it. In the days surrounding this date, if the weather is clear, we can see it low in the western sky at dusk.
During this elongation, there are no bright stars near the area where Mercury is located. The -2.0 magnitude Jupiter will be at a lower altitude, making it relatively easy to identify Mercury.
Sun: At the beginning of the month, the Sun’s apparent Right Ascension and Declination are 22^h 46^m 18.342^s and -07^\circ 48' 05.356''; at the end of the month, they are 00^h 36^m 30.808^s and 03^\circ 56' 04.430''. This month, the Sun moves from Aquarius to Pisces.
Moon: The Moon passes apogee and perigee on March 6 at 16:00 and March 20 at 03:00, respectively. The times for New Moon, First Quarter, Full Moon, and Last Quarter are the 5th at 04:46, 13th at 07:45, 20th at 02:10, and 26th at 20:07.
Mercury: Evening star. Its distance from the Sun increases daily, appearing in the southwestern sky at sunset. Its altitude at sunset gradually increases, and observation conditions are improving. On March 23, Mercury reaches Greatest Eastern Elongation with a maximum angular distance of 19^\circ from the Sun, an altitude of about 17^\circ, and a magnitude of about -0.4. This is the second best period for observing Mercury this year. After the elongation, Mercury rapidly approaches the Sun. On the 10th at 02:00, Mercury is in conjunction with Uranus, 0.4^\circ north of Uranus. On the 17th at 01:00, Mercury is in conjunction with Jupiter, 2^\circ north of Jupiter.
Venus: Morning star. In March, Venus moves from Sagittarius through Capricorn into Aquarius. It is located in the southeastern sky at dawn. By the end of the month, its altitude at sunrise drops to about 14^\circ, with a magnitude of about -0.4. Observation conditions are becoming increasingly unfavorable. On the 1st at 12:00, Venus is in conjunction with the Moon, 2^\circ south of the Moon. On the 27th at 09:00, Venus is in conjunction with Neptune, 0.2^\circ south of Neptune. On the 31st at 21:00, Venus is in conjunction with the Moon, 6^\circ south of the Moon.
Mars: In March, Mars moves prograde from Aquarius to Pisces. Mars is close to the Sun and difficult to observe.
Jupiter: In March, Jupiter moves prograde in Pisces. It is in the southwestern sky at sunset and moves to the northwestern sky in late March. It sets shortly after sunset, with a magnitude of about -2.1, making it difficult to observe. On the 7th at 13:00, Jupiter is in conjunction with the Moon, 7^\circ south of the Moon.
Saturn: In March, Saturn is in retrograde in Virgo. As Saturn moves further from the Sun, its rising time in the east moves earlier to around 19:40, with a magnitude of about 0.4. This is a good time to observe Saturn. On the 21st at 08:00, Saturn is in conjunction with the Moon, 8^\circ north of the Moon.
Uranus: Located in Pisces. It is low in the western sky at sunset and approaches the Sun daily. After its conjunction with the Sun on the 21st, it will appear low in the eastern sky at sunrise and cannot be observed.
Neptune: Located in Aquarius. It is low in the eastern sky at sunrise, close to the Sun, and cannot be observed.
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