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A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Sean C
Date: 2015 Apr 9, 21:53 -0700
Paul and Herbert,
Wow, I cannot believe I never noticed that option! I must have looked right past it a hundred times. Holy cow. O_o Sure enough, if I set it to "Eastern U.S. (-5)" + DST, the result is:
Sun
Newport News, Virginia, United States
Location: W 76°28'36.0", N37°03'18.0", 10m
(Longitude referred to Greenwich meridian)
Time Zone: 4h 00m west of Greenwich
Date Begin Rise Az. Transit Alt. Set Az. End
(Zone) Civil Civil
Twilight Twilight
h m h m ° h m ° h m ° h m
2015 Apr 07 (Tue) 06:17 06:43 81 13:08 60S 19:33 279 20:00
2015 Apr 08 (Wed) 06:15 06:42 80 13:08 60S 19:34 280 20:01
2015 Apr 09 (Thu) 06:14 06:40 80 13:08 61S 19:35 280 20:02
2015 Apr 10 (Fri) 06:12 06:39 79 13:07 61S 19:36 281 20:03
However, I'm still not sure about the "/////" result. If you look back to my first post on the subject, you will see the result for the following day was:
Date Begin Rise Az. Transit Alt. Set Az. End
(UT1) Civil Civil
Twilight Twilight
h m h m ° h m ° h m ° h m
2015 Apr 09 (Thu) 10:14 10:40 80 17:08 61S 23:35 280 00:01
This must mean that the end of civil twilight at this location occurs at 1 minute into the next day UT1 (Apr. 10th), right? So, shouldn't MICA have displayed either "00:00" or "00:01"...or even "?????" (Phenomenon is indeterminate.) for the UT1 calculation on Apr. 8th? As it is, it seems to suggest that the Earth stops rotating briefly. Although that would obviously be absurd.
Thank you both very much for your consideration and replies.
Regards,
Sean C.
