The spectrograph camera does not have a shutter, so even though bias frames are zero second exposures, you still need to take them when no light can reach the detector. Ideally while the mirror cover is still closed, or at least not while pointing to an object, or while an arc lamp or the slit illumination etc is on. The bias level on SpUpNIC is stable, but these frames take next-to-no time, so just snap a bunch of them (say 25?) every day.
====Dome Flatsflat recipe====
[[File:dome_flats.jpg|thumbnail]]
Dome flats give a measure of the pixel-to-pixel sensitivity variations over the CCD. The dome's white flat-field screen is not perfectly evenly illuminated by the lamps on the top end of the telescope, but the light goes through the slit, gets collimated, diffracted and re-focussed, so that is not a problem. We do not use the sky for this as you would get spectra of the Sun!
- # First check the observing floor for ladders or obstructions. If you're observing remotely you can use the webcam, or if you're in the dome just pop upstairs.
- On the TCS, click the grey "FLOOR" button near the top to change the telescope control to "TCS".
- Click the red "Telescope Power is OFF" button on the top left. Telescope power will switch on, the button will turn green, and the various subsystem statuses will be populated.