NavList:

I would like to explain how I have been effectively performing CN with a SLR 10mp digital camera using 50mm, 100mm, and 200mm lenses. Lens distortion and tangent geometry are corrected for together for each individual fixed lens by observing the Sun or Moon every two minutes then graphing the minutes of arc per pixel derived from reduced observation at a known GPS position. This allows the entire field of view along a central axis to be usable (24� for a 50mm lens). Marcel helped convert my graphed data to a simple formula (.371 x pixels + 12.35 = MOA for a fixed Pentax 50mm lens). This formula works great at +/- one MOA through the entire 24� field. The trick for consistency is in how the camera settings and polarizers are used. All my images are shot at f22 and infinite focus (any deviation causes problems). The polarizers are held out in front of the lens at arms length. This mysteriously improves results. I strongly encourage others to try this neat way of generating an LOP from the Sun or Moon during the day.

Greg Rudzinski
----------------------------------------------------------------
NavList message boards and member settings: www.fer3.com/NavList
Members may optionally receive posts by email.
To cancel email delivery, send a message to NoMail[at]fer3.com
----------------------------------------------------------------