Guidelines for Selecting Observing Settings for Classic


For stars brighter than K < 5.5 mag, use destructive mode.
For stars fainter than K > 5.5 mag, use non-destructive mode if needed.

If possible, stay at 750 Hz so that the noise peaks are furthest from the fringe window.

If recording in non-destructive mode, check for saturation which occurs at sum ~ 300 counts (150 counts per pixel). You don't have to worry about saturation in destructive mode.

To determine the camera speed, go to the faintest star in the bracket:
  • In H-band you want the sum to be at least 50 counts (H-band has very little background)
  • In K-band you want the sum to be at least 50 counts + the background. Close both shutters to estimate the counts in the background.

In general, use the long scan length. But if the seeing is very good and the fringes aren't bouncing around in the waterfall, you might want to try the short scan.

Re-align NIRO about once every hour. Make sure that you complete a calibration bracket before aligning or moving the reference cart.

Please record the data entries into the electronic observing logs. In the comments section, please make a note of the camera settings and indicate when NIRO alignments are done or if the reference cart position was moved.
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