NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2010 Oct 12, 17:56 -0700
This version of the 2102-D and radar plotting sheet (see linked images) has GHA of Aries, date, and day going clockwise and zone time going counter clockwise. The zone time result requires correcting for the difference between the observers longitude and the zone meridian.
Use the red template to plot the Sun onto the 2102-D base disc with the current day's declination and time of meridional passage from the Nautical Almanac. Set Aries to month and day on plotting sheet, set red template to time of meridional passage, mark disc through slot at the correct declination.
Now the 2102-D is ready to get civil twilight time and sky:
1. Set Aries to month and day.
2. Rotate latitude template so that the Sun is 5° to 10° below zero altitude.
3. Read zone time of civil twilight and select stars.
Image examples are for 12 October 2010
-meridional passage Sun plot.
-civil twilight template set.
Greg Rudzinski
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