Archive
02/24/2015 – Ephemeris – Not all greatest elongations of Mercury are equal
Ephemeris for Tuesday, February 24th. The sun will rise at 7:29. It’ll be up for 10 hours and 54 minutes, setting at 6:23. The moon, 1 day before first quarter, will set at 1:28 tomorrow morning.
Today Mercury is at its greatest distance west of the Sun. Don’t go out to view Mercury right before sunrise unless you’re way south of here, or better yet south of the equator. Because of the tilt of the Earth’s axis and our latitude the positions of the planets that appear near the sun at sunrise and sunset are easier or harder to spot depending on the season. The best time to spot Mercury when it’s at its greatest elongation or distance east of the Sun is on late winter and spring evenings, or late summer and autumn mornings when Mercury is west of the Sun. Since the seasons south of the equator are opposite ours the same rule holds. It’s late summer down there which is favorable to spot Mercury in the morning, but not here.
Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

