By Richard Hall
All times are adjusted for daylight saving
The chart shows the heliocentric orbital positions of the planets for March 1st 2010. The planets are orbiting in an anti-clockwise direction and smaller images show the positions of the inner planets for February 15th and March 15th. The orbits of the inner planets, Mercury, Venus, Earth and Mars, are to scale. Planets beyond Mars are placed in shells. These are Ceres, Jupiter, Saturn, Uranus, Neptune, Pluto, and Eris. A line drawn from the Earth through the Sun reveals the constellation of the Zodiac that the Sun is moving through. Because the Earth rotates in an anti-clockwise direction planets to the right of this line rise after midnight and are therefore morning stars. Those to the left are evening stars.
| MERCURY - is a bright evening star in February. On February 20th it will be seen in the west after sunset as a magnitude -0.4 star in Capricornus and, in a telescope, it will look like a tiny gibbous moon (phase 88%) 5.1” in diameter. The planet reached greatest elongation on January 27th and is now moving back towards the Sun. In early March it will be lost in the evening twilight and will not be seen again with the unaided eye until late May. Mercury reaches superior conjunction (the far side of the Sun) on March 15th.
|  | VENUS - is an evening star but remains close to and sets shortly after the Sun throughout February and March. In May it will emerge from the twilight to become prominent in our western evening sky for most of the rest of the year. |  | MARS - is a bright reddish evening star in Cancer. At the beginning of March its magnitude will be -0.6 and in a telescope it will show a small disc 12.1” in diameter. Opposition occurred on January 30th. However, this was one of the most unfavorable of oppositions because Mars is close to aphelion – its most distant orbital point from the Sun. Aphelion occurs on March 31st. |
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VESTA is the brightest asteroid seen from Earth and reaches opposition in Leo on February 20th. On this date its distance will be 1.41 A.U. (211 million km) and its magnitude will be +6.1, which makes it just visible with the unaided eye from a dark-sky site. Vesta has a diameter of 525 kilometres. Its co-ordinates and magnitude are as follows: R.A. Dec. Magnitude
Feb 21 10h 15m 47.2s +20o 09’ 57” 6.1
Mar 01 10h 08m 00.1s +21o 07’ 05” 6.2
Mar 11 09h 59m 09.3s +22o 01’ 25” 6.4
Mar 21 09h 52m 22.0s +22o 33’ 11” 6.6
Mar 31 09h 48m 24.6s +22o 42’ 04” 6.8
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| JUPITER - is in conjunction with the Sun on March 1st and will not be visible for most of February and March. Towards the end of March it will reappear in the eastern dawn twilight in the constellation of Aquarius. Its magnitude will be -2.0 and its telescopic diameter 33.4”.
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SATURN - reaches opposition in Cancer on March 22nd and aphelion (its most distant orbital point from the Sun) on March 31st. At opposition Saturn’s distance will be 70.72 light-minutes, its magnitude +0.5, and its telescopic diameter of its orb 19.5”.
|  | URANUS - is in conjunction with the Sun on March 18th and will not emerge from the dawn twilight until April. The planet is in Pisces and its magnitude is +5.9.
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NEPTUNE - is in conjunction with the Sun on February 15th. In mid-March it will emerge from the dawn twilight and moves from Capricornus into Aquarius in the second half of the month. . Its magnitude will be +8.0 and in a telescope it will be seen as a tiny bluish disk 2.2” in diameter.
|  | PLUTO - is a morning star in the constellation of Sagittarius. At magnitude +14.0 it is visible only in large telescopes.
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