In a message dated 98-08-15 00:42:34 EDT, you write: << When I get haze or thin cirrus clouds, etc... I do the same thing: LM estimates over different areas of my field. I'll star count my triangles as often as the sky appears to change >> Even when the skies are clear, it's best to make star counts from two star count areas each time and then they get averaged. George Zay