This month we bid farewell to Jupiter as it sinks into our W evening twilight. As it does so, though, the largest planet meets and passes its smallest sibling, Mercury, as the latter begins its best evening apparition of the year. Another encounter occurs when Nasa's Messenger probe enters orbit around Mercury on the 18th.
Jupiter shines brightly at mag -2.1 but its altitude in the W 30 minutes after sunset falls from 18° tonight to only 5° by the 20th and we soon lose it as it heads for solar conjunction on 6 April.
On the evening of 6 March, the very slender, and strongly earthlit Moon stands 6° to the right of Jupiter and 13° directly above Mercury which, at mag -1.4, might just be visible through binoculars in the early twilight. Look for the Moon 10° above Jupiter on the next evening and watch Mercury climb to lie 2.0° to the right of Jupiter on the 16th and 5° above Jupiter on the 19th. By then Mercury sets 109 minutes after the Sun and should be an easy naked-eye object at mag -0.6 if our W horizon is clear. Later in the month, it starts to fall back into the twilight and fade quickly to mag 2.0 by the 31st.
Orion is still resplendent in the S at nightfall but by our map times it is sinking in the W as Leo reaches the meridian. Following Leo is Virgo with its bright star Spica and the slightly brighter Saturn which improves from mag 0.5 to 0.4 this month. The latter, some 10° NW of Spica, rises in the E two hours before our map times and crosses the meridian in the early morning. When the just-gone-full Moon forms a triangle with Spica and Saturn on the 19th/20th, Saturn appears 19 arcsec wide through a telescope while the rings are 43 arcsec wide and have their N face inclined to us at 9°.
Venus, brilliant at mag -4.1 and alongside the waning Moon tomorrow, is very low in the ESE to SE just before dawn.
Jupiter shines brightly at mag -2.1 but its altitude in the W 30 minutes after sunset falls from 18° tonight to only 5° by the 20th and we soon lose it as it heads for solar conjunction on 6 April.
On the evening of 6 March, the very slender, and strongly earthlit Moon stands 6° to the right of Jupiter and 13° directly above Mercury which, at mag -1.4, might just be visible through binoculars in the early twilight. Look for the Moon 10° above Jupiter on the next evening and watch Mercury climb to lie 2.0° to the right of Jupiter on the 16th and 5° above Jupiter on the 19th. By then Mercury sets 109 minutes after the Sun and should be an easy naked-eye object at mag -0.6 if our W horizon is clear. Later in the month, it starts to fall back into the twilight and fade quickly to mag 2.0 by the 31st.
Orion is still resplendent in the S at nightfall but by our map times it is sinking in the W as Leo reaches the meridian. Following Leo is Virgo with its bright star Spica and the slightly brighter Saturn which improves from mag 0.5 to 0.4 this month. The latter, some 10° NW of Spica, rises in the E two hours before our map times and crosses the meridian in the early morning. When the just-gone-full Moon forms a triangle with Spica and Saturn on the 19th/20th, Saturn appears 19 arcsec wide through a telescope while the rings are 43 arcsec wide and have their N face inclined to us at 9°.
Venus, brilliant at mag -4.1 and alongside the waning Moon tomorrow, is very low in the ESE to SE just before dawn.
March diary
1st 04h Moon 1.6° N of Venus.
4th 21h New moon.
7th 05h Moon 7° N of Jupiter.
13th 00h First quarter.
16th 17h Mercury 6° N of Jupiter.
19th 18h Full moon.
20th 23:21 Vernal equinox.
21st 00h Moon 8° S of Saturn.
23rd 01h Mercury farthest E of Sun (19°).
26th 12h Last quarter.
27th 01h GMT = 02h BST Summer Time begins.
31st 14h BST Moon 6° N of Venus.
1st 04h Moon 1.6° N of Venus.
4th 21h New moon.
7th 05h Moon 7° N of Jupiter.
13th 00h First quarter.
16th 17h Mercury 6° N of Jupiter.
19th 18h Full moon.
20th 23:21 Vernal equinox.
21st 00h Moon 8° S of Saturn.
23rd 01h Mercury farthest E of Sun (19°).
26th 12h Last quarter.
27th 01h GMT = 02h BST Summer Time begins.
31st 14h BST Moon 6° N of Venus.
