Thursday, September 11, 2008


Yesterday the planet Mercury reached its greatest elongation , 27 degrees,(its highest above the horizon), but today it is still quite visible in the evening twilight. During the past week Mercury has formed a triangle in the evening sky with the planets Venus and Mars, and tonight Venus and mars make their closest approach, being only 18 arc-minutes from each other. Venus, shining at a magnitude of -3.9, will be the brightest of the trio, Mercury will have a magnitude of -0.2 and Mars, the dimmest of the pair, will shine at about 1.7. The diagram to the left shows how the planets will be on a line of sight this evening.

Mars will be located just slightly left of and below Venus, and Mercury will be below the air and to the left. The bright star Spica will also be visible further to the left. You will need binoculars or a moderate power telescope to view the trio because of the closeness of Mars and Venus and because of the interference of twilight. People living further south than Canada will have a better chance of viewing as the planets will appear higher above the horizon to them. Conditions are likely to be overcast here in Winnipeg, but people elsewhere may have better luck.

Good viewing.

No comments: