The following notes are generally useful for any observing program. Note that, due to controller electronics, actual exposures times are slightly longer than indicated by the data-taking system. Consult the users' logbook, the Lirctop log, or a support scientist, if you are not sure of the length of the delay. A program's particular requirements will dictate the specifics of the observing strategy, but an observer will typically emerge from his or her observing run with some combination of source frames, sky frames, standard stars, darks, flats, and bias frames. See Reduction Techniques for suggestions on reducing LIRC-II data.
Observations usually consist of multiple exposures of the same target, which are later combined.
Because of the strong sky contribution, sky subtraction is of fundamental importance. Sky frames are generally produced at the same rate as target frames, and near them in space and time. Near-infrared sky brightness can vary significantly on short time scales, requiring frequent sky frames. Dithering for sky subtraction and to remove bad pixels is a common practice. Darks are made by setting the filter and lens wheels to their dark positions, so that the array sees only the cold metal of the wheels.