NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Geoff Hitchcox
Date: 2023 Oct 19, 18:48 -0700
Hi Kermit,
I thought you might like to see what the "Swiss Ephemeris" (JPL ephemeris based) gives for the Occultation - using the following command line (all times below are UT).
./swetest -ejpl -occult -pf -b01.01.1924 -local -xfRegulus -geopos288.408833,41.845167,107
Total(sunrise) 23.10.1924 ( dt=23.7 )
Immersion = 10:58:01.6
Emersion = 12:11:33.2
Because it was flagged with "sunrise" - I then asked for the time of Sunrise with this command.
./swetest -ejpl -b23.10.1924 -n1 -s1 -geopos288.408833,41.845167,107 -p0 -rise
Sunrise on the 23.10.1924 = 11:07:45.4
Comparing above *Occult* times with Sunrise gives:
Immersion = 10:58:01.6 (9 mins 43.8 secs BEFORE Sunrise)
Emersion = 12:11:33.2 (1 hr 3 mins 47.8 secs AFTER Sunrise)
So to me, it is amazing they were able to get anywhere near a *decent* value (back in 1924) - because of light pollution from the Sun!
Regards, Geoff Hitchcox, Christchurch, New Zealand.
