NavList:
A Community Devoted to the Preservation and Practice of Celestial Navigation and Other Methods of Traditional Wayfinding
From: Greg Rudzinski
Date: 2010 Jun 25, 17:48 -0700
The linked graph shows pixels (Px vertical) vs. minutes of arc per pixel (MOA/Px horizontal) for a 50mm Pentax prime lens. Data for the graph was figured from a set of timed setting Sun observations between 24° and 12° of altitude. Each image data point is generated by working an Hc backwards to get an Hs. The Hs in minutes of arc is divided by observed image pixels to obtain the MOA/Px.
Subsequent image altitudes can be derived with the graph by multiplying an image altitude in pixels by the MOA/Px from the graph to get the altitude Hs in MOA.
Greg Rudzinski
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