FORS1: Sky Flats and Rotator Effect

	FORS1: Sky Flats and Rotator Effect

Median Twilight Image (all frames normalized by their median before averaging and corrected for 4-port structure)	Median of Normalized Twilight Images at Rotator Angle 0	Median of Normalized Twilight Images at Random Rotator Angle	Time Frame and Rotator Angle Distribution
			B_UT2_2CCD: 134 frames April - September 2007 (distribution of rotator angles)
			U_UT2_2CCD: 106 frames April - September 2007 (distribution of rotator angles)

(uncorrected median twilight image)			B_UT2: 298 frames September 2004 - December 2005 (distribution of rotator angles)
(uncorrected median twilight image)			U_UT2: 246 frames September 2004 - December 2005 (distribution of rotator angles)

(uncorrected median twilight image)			B_UT1_C: 234 frames December 2002 - March 2004 (distribution of rotator angles)
(uncorrected median twilight image)			U_UT1_C: 214 frames December 2002 - March 2004 (distribution of rotator angles)

(uncorrected median twilight image)			B_UT3: 266 frames September 2001 - September 2002 (distribution of rotator angles)
(uncorrected median twilight image)			U_UT3: 243 frames September 2001 - September 2002 (distribution of rotator angles)

(uncorrected median twilight image)			B_UT1_B: 137 frames August 2000 - February 2001 (distribution of rotator angles)
(uncorrected median twilight image)			U_UT1_B: 175 frames August 2000 - February 2001 (distribution of rotator angles)

(uncorrected median twilight image)			B_UT1_A: 142 frames April 1999 - September 1999 (distribution of rotator angles)
(uncorrected median twilight image)			U_UT1_A: 77 frames April 1999 - September 1999 (distribution of rotator angles)