Calculation of the differential trailing		

Differential trailing at the north and the south of the CCD.		



	Size of the field of the CCD in arc minutes	

	Width	Height
ST-7	31,56	21,04

declination	20	

differential trailing	2,10909416	
in arc sec		



	focal length in mm			750
	pixel size in 1/1 000 000 m			9
	pixels per line (width)			765
	pixels per column (height)			510


pixel size in arc seconds		2,47517767		
CCD field width in arc minutes		31,5582937		
CCD field height in arc minutes		21,0389446		


	width	height		
	31,5582937	21,0389446		

Declination in degree	20

differential trailing	2,10887435
in arc sec	



Differential trailing =   0,5 * HeightCCDArc*WidthCCDArc*tan(declination)