You don't have to be a devotee of Hermes/Mercury to get excited about observing the planet named for the God. But it helps.Mercury is very difficult to observe with the naked eye. But another good opportunity for such observation is approaching. Mercury will be at its "Greatest Eastern Elongation" on December 18, just two days after the Dark Moon on December 16. An "elongation" of Mercury is when the little bugger is at it's maximum separation from old Sol, and this is not just the "best" time for observing Mercury - somewhere close to a significant elongation is about the only time you really have a shot. "Eastern" elongation means that Mercury is trailing the Sun - so it is observable in the evening.
On the night of the December 18, 2009, Mercury will be slightly more than 20 degrees from the Sun. Which is still not very far, but is pretty good for Mercury. Mercury will begin to be visible under (very!) optimal conditions as early as November 25th. Optimal conditions means you have an absolutely clear view of the horizon, no light pollution, and no clouds.
January of this year was the first, and so far the only, time I have seen Mercury. I hope to get one more in before the end of this year!!
I will be posting a lot more about this in the coming weeks and days.
Correction: Mercury actually can be observed when light pollution is present. My two sightings last Dec/Jan were both in the DC metro area. One was at the Rockville Metro Station! I wonder if I will attract attention if I just hang out at the Rockville Metro scanning the western horizon with my binoculars?
ReplyDeleteSo the two most important things are that the western sky must be CLEAR and you must have an unobstructed view of the horizon.