Home > Concepts, Ephemeris Program > 04/28/2015 – Ephemeris – Why do the stars of winter disappear so fast?

04/28/2015 – Ephemeris – Why do the stars of winter disappear so fast?

April 28, 2015

Ephemeris for Tuesday, April 28th.  Today the Sun will be up for 14 hours and 6 minutes, setting at 8:43.   The Moon, 3 days past first quarter, will set at 4:32 tomorrow morning.  Tomorrow the Sun will rise at 6:36.

At 9:30 p.m. the winter constellation of Orion is above the western horizon, but barely visible in the bright twilight.  The sun is moving eastward and northward, setting at about 1 minute and a quarter later each night.  That minute and a quarter is due to the Sun’s northward motion north.  The Sun’s eastward motion, which is actually the Earth’s orbital motion around the sun, makes the stars set approximately 4 minutes earlier each night.  That’s because our time is kept based on the Sun, not the stars.  What happens is that the winter stars seem to disappear rather rapidly.  We lose the bright stars and constellations of winter which are replaced by the sparser constellations of spring.

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

 

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