Median Twilight Image
(all frames normalized by their median before averaging; frames before April 2002 corrected for 4-port structure)
B_UT1_2CCD: 256 frames
June 2004 - December 2005
(distribution of rotator angles)
U_UT1_2CCD: 264 frames
B_UT4_2CCD: 289 frames
April 2002 - October 2003
U_UT4_2CCD: 199 frames
(uncorrected median twilight image)
B_UT4: 199 frames
June 2001 - March 2002
U_UT4: 117 frames
June 2001 - November 2001
B_UT2_B: 125 frames
December 2000 - May 2001
U_UT2_B: 88 frames
B_UT2_A: 155 frames
May 2000 - December 2000