A guide to Suprime-Cam exposure times
Saturation is almost inevitable for broad-band observations with Suprime-Cam. The large pixel size of the instrument and light gathering power of the primary mirror produce high count rates per pixel, and a number of bright stars will always be present in the large field of view, even at high Galactic latitudes.
The following table shows saturation magnitudes (defined as >150 000 e-) for different exposure times in good seeing (0.5''), when approximately 10% of the light from an unresolved source falls in the peak pixel. A moderately dark sky (approximately 3 days from New Moon) has been assumed. Magnitudes for the Johnson-Cousins filters are on the Vega system, and those for the SDSS filteres, narrowband filters, and a Y band filter are on the AB magnitude system.
(2)Commonly-used exposure times. The sky background levels in each band are approximately half the saturation level with these exposure times. Since the sky background in bands redder than Rc-band varies with time, the observer must adjust the exposure time to avoid the sky background saturating. (The variation is as large as a factor of 4 in z'-band, smaller in Rc-band.)