Archive for May 19, 2016

05/19/2016 – Ephemeris – Daylight Saving Time in West Michigan

May 19, 2016 Comments off

Ephemeris for Thursday, May 19th.  Today the Sun will be up for 14 hours and 59 minutes, setting at 9:09.   The Moon, 2 days before full, will set at 5:49 tomorrow morning.  Tomorrow the Sun will rise at 6:08.

It is nearing summer and the powers that be have bequeathed on us daylight saving time, even starting it before the end of winter since 2007.  It is a thing that amateur astronomers hate.  This time of year through the end of July the Sun just sets too late, and if one has a day job, it’s nearly impossible to stay up long enough to start observing at 11 p.m. or midnight, and be bright-eyed and bushy-tailed the next morning.  Nautical twilight, when the sea horizon is no longer discernible ends at 10:28 p.m. tonight, and astronomical twilight, when it’s pitch dark, ends at 11:19.  It gets worse the farther north and west you go in the Eastern time zone.   At least this year we have three planets to entertain us in the evening twilight.

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


Time Zone Map

Our place in the Eastern Time Zone. Source  If you are using Firefox right-click on the map and select View Image to enlarge.

We are near longitude W 86°.  Our Eastern Standard time meridian is W 75°, which runs through Philadelphia, which I’ve added to the map, southwest of New York.  With 15° per hour that makes that 44 minutes behind Philadelphia.  Theoretically time zones should extend 30 minutes on either side of a standard time meridian.

During daylight time our time meridian is W 60°, which is off the map.  That meridian just ticks the eastern end of Nova Scotia in Canada.  For us near 45° north latitude astronomical twilight ends shortly after midnight.