After the user selects the Add button, a GUI like Fig. \ref{fig:sequence} will pop up. Flat field and wavelength calibration observations are added before and after the requested target observation. The user may drag and drop these observing elements to reorder them, or hit the X button to delete them. Clicking on an observation will allow it to be modified. Clicking the + button will allow the user to add one of the following:

Spectrum: Add another target in sequence

Observing constraint: Add an airmass constraint.

Time window: Specify a time window in which to take the observations.

Cadence: Specify a cadence with which to repeat the observations. This consists of a period and a jitter. Period is how often (in fractional hours) the observations will be repeated. Jitter is the maximum allowed time difference between frames – the larger the jitter, the more likely each repeated request will be executed.

Calibration: Add an arc or flat.