If the temperature wanders by more than 0.2 degree, start to worry. Since both the response and the noise of the chip are temperature sensitive, it is quite important that it remain constant. If not, turn the controller off for 30 seconds or so, then back on. If you still don't get the green light, call for help. The flat field lamps are mounted on the struts of the telescope a few feet below the secondary ring.
Power is provided by a variable power supply on the floor to the right of the door.
The lamps are 12 volt incandescents, so please don't exceed 12 volts on the supply voltage or they'll soon burn out. Changing the voltage allows you to change both the brightness and the color temperature, unfortunately not independently. Dome flats are taken on the white patch on the inside of the shutter, or more usually just on the white windscreen. Do not forget that in order to get the flat field light to the detector, the secondary rainscreen halfway down the telescope must be open, the mirror ccover must be open, the diagonal mirror must be in the out position, the manual dark slide must be open, and the aperture and filter wheels must be properly set. If you're at the red end of the spectrum, you may choose to take a longer exposure at lower lamp intensity in order to get a more satisfactory ratio of light at the two ends of yoru spectrum, and vice versa for the blue.