Home > Concepts, Ephemeris Program, Venus > 06/04/2015 – Ephemeris – Venus’ greatest eastern elongation from the Sun is Saturday

06/04/2015 – Ephemeris – Venus’ greatest eastern elongation from the Sun is Saturday

June 4, 2015

Ephemeris for Thursday, June 4th. Today the Sun will be up for 15 hours and 24 minutes, setting at 9:23. The Moon, 2 days past full, will rise at 11:06 this evening and tomorrow the Sun will rise at 5:58.

On Saturday Venus will reach its greatest eastern elongation or separation from the Sun of 45.4 degrees angle. It’s phase should be that of exactly half illuminated by the sun. The problem is that the date it is exactly half illuminated can vary from 1 to 4 days from the greatest elongation. Of course this is something that has to be seen in a telescope. Try to catch Venus in bright twilight so its bright glare is minimized. I find that a moon filter fitted to the eyepiece gets rid of the glare nicely. After that time Venus will to begin to move toward the Earth, then curve around in its orbit to pass between the Earth and the Sun. As it does so it will increase its apparent size and its phase will become a crescent.

Times are for the Traverse City/Interlochen area of Michigan. They may be different for your location.

Addendum

Venus at greatest eastern elongation

Venus at elongation with a plot of its orbit as seen from Earth at 10:30 p.m. June 6, 2015. Note that the orbit appears at a line. It is this time of year that the Earth passes through the plane of Venus’ orbit. Back in 2012 this occurred when Venus was at inferior conjunction on June 5th. It passed in front of the Sun in the rare transit of Venus. Created using Stellarium.

Greatest elongation diagram

Diagram showing the geometry of a greatest elongation. Note that the sight line is perpendicular to the Venus-Sun line. So the phase should be exactly at dichotomy (half illuminated). Additional lines added to an uncredited diagram.

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