During the very pleasant Europa get-together at Bidford yesterday,
Peter Kember was saying he'd been sorry that work commitments made
him miss flying on the evening of the longest day, for no reason
other than just to be able to be legally aloft in day-VFR as late as
possible.
I said maybe he hadn't missed out as I had the feeling that the times
of the earliest sunrise and the latest sunset did not necessarily
coincide with the longest day, and so I have run a few dates through
my Astronomical Algorithms program (based on work by Jean Meeus &
Jeffrey Sax), coming up with the following predictions for SR & SS at
my local field EGBJ, 51 53 37N, 002 09 56W:
10-6-01 03:50 20:27
11-6-01 03:49 20:27
12-6-01 03:49 20:28
13-6-01 03:49 20:29
14-6-01 03:49 20:29
15-6-01 03:49 20:30
16-6-01 03:49 20:30
17-6-01 03:49 20:31
18-6-01 03:49 20:31
19-6-01 03:49 20:31
20-6-01 03:49 20:32
21-6-01 03:49 20:32
22-6-01 03:49 20:32
23-6-01 03:50 20:32
24-6-01 03:50 20:32
25-6-01 03:50 20:32
26-6-01 03:51 20:32
27-6-01 03:51 20:32
28-6-01 03:52 20:32
29-6-01 03:52 20:32
30-6-01 03:53 20:31
So, looks like around here the earliest sunrise is on 16th or 17th
June, and the latest sunset is around 24th/25th - today or tomorrow
at the time of writing - so, Peter, you still have time to do it!
These effects are, I guess, different at other latitudes - I haven't
bothered to check elsewhere. I plan at some stage to put a loop in
the program to make it more convenient to tabulate at range of dates,
but other stuff is higher priority now. I could also change the
output to give resolution to seconds, which would confirm my
guesswork above, but that sort of precision is not usually needed!
You guys with almanacs built into your GPS boxes can no doubt confirm
what's happening at your own location.
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