Science Operations


Programs are typically run in queue. It is important to to be aware of overheads when receiving your allocated time. The time allocated to each program is clock time and includes acquisition, calibrations, and other detector and telescope overheads. 

Obtaining astronomical observations at any telescope will typically face four different sources of overhead: from the telescope, instrument, detector and any operation that requires human interaction. The Table below summarizes these overheads.

 Source of Overhead  Action Type  Typical Time [sec]  Maximum Time [sec]
 Telescope  Preset  75  300
 Pointing Correction  150  300
 AO setup  180  240
 Dither(AO) 3  20
 Instrument  Camera, Pupil Alignment  60  300
 Filter Changes  10  60
 Troubleshooting 5 1800
 Human Element  Field/Source Identification  5  300
 Imaging Alignment/Setup  20  300
 Ales Alignment/Setup  300  900
 NRM Alignment/Setup  300  900
 Nulling Alignment/Setup  600  3600
 Troubleshooting  60  1800
 Source of Overhead  Action Type  LMIRCam [sec]  NOMIC [sec]
 Detector Fast Mode Full frame
Medium Mode Full frame
Slow Mode Full frame

Note that Fast mode has subwindowing.  Minimum time scales linearly with vertical pixel length.

The above times are estimates and may be refined.  Detector times TBD

Twilight is used for initial AO setup and checkout and for the initial instrument alignment. As a result, start of night set up overheads are therefore not passed on to the users. Calibration frames, such as Darks, are taken during telescope transition states while waiting for the AO to reacquire as another means of increasing observing efficiency. For ALES observations, it is necessary to take the wavelength calibrations before moving any optics to ensure consistent results. It may be necessary to take these during the night depending on the programs. These wavelength calibrations take approximately 20 minutes.