next up previous contents
Next: Taking an Exposure Up: Observing with WHIRCAM Previous: Initial Engineering Tests

Observing Modes

  There are currently four observing modes with WHIRCAM. These are:

The two advantages of ND_STARE over STARE is that (1) the direct read-out architecture of the detector means that the integrated charge may be sampled non-destructively and an improvement in read-noise is thus obtained by making multiple reads, and (2) the reset level can vary, so you automatically subtract the latest reset in ND_STARE. However, there is also an extra time overhead in each readout, so for very short exposures (as in S+A) STARE is better. The shortest integration where ND_STARE is likely to be beneficial is about 1 sec.

Shaun Hughes
Thu Mar 14 14:48:38 GMT 1996