Examples of image problems

Focus dots: 486370o00may990p03.fits
Cross dots: 486370o00may990p03.fits
Smearing: Typically on CCD04 for the May 1999 run and on CCD00 for subsequent runs. Affects the photometry at less than the 1% level. Does not appear to affect the astrometry, but careful tests have not yet been done. The exact area seems to vary from exposure to exposure.
Smearing: The figure shows the effects of smearing on the photometry. The photometry on two overlapping images is compared in the smeared section
Trailed images: 486371o07may990p03.fits
Ghost image: Bright stars can leave a residual image on the CCD which is visible on the next exposure.	550368o11sep000p04.fits 550369o11sep000p04.fits

Masks: May 1999
Masks: Nov 1999
Masks: Apr 2000-2
Masks: Sep 2000
Masks: Oct 2000-1
Masks: Oct 2000-3