NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Byron Franklin
Date: 2013 Jan 12, 20:07 -0800
Byron:John My horizon Disk can be place at the correct Lat & Long.
Not only the over-head but the accuracy near the Horizon is very good. The shape of the Horizon and AZ& HT change very little with a small change
of Lat. Say 45 placed at 41. It's the placement of the 10 degree jump of the 2102-D that hurts.
The change in the stars SHA & Dec for the Star Disk will be good for our life time ++++++.
To find the GMT of any set up, occurrence, you need only - the M&D GMT.
For the time of Sunrise/ Set can be placed on the star disk by NA SR, local newspaper,ect.
from the news SR @ 07:12 +5 ZT I have checked, it, close to the NA, Get the time of Sun rise. Get the GMT for that Month & day Jan 12=19:28 add the GMT of paper SRGMT 12:12 Place Aries @07:40. Next run a line from the Pole to the GMT 12:12SR on the outer base plate. The sun is on the horizon and the line. Marks the sun on the star disk at the horizon with a grease pencil, read the amplitude bearing 117. You can than track the sun across your sky.
The accuracy: many be + or – a few degrees amplitude and a few minutes for LAN or sun set, or any time between. Another way would use the NA DEC22 anduse Poler Distance of 22+90 draw a arc You get the same Amplitude. That takes 2 Minutes.
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