Setup with LRS2
Minimum exposure times are 15 seconds. It is advised that the PI stay above this value as there is some small uncertainty in the shutter timings at the present time.
Setups times are typically less than 10 minutes for all targets. For targets bright and point-like enough for guiding on the ACQ camera during setup, we recommend requesting a DirectACAM setup method. For sources fainter than 20.5 mag or resolved, a ACAMblind setup is preferred - we will use other stars within the ACQ camera field of view to position your target as requested. A blind setup is also the best choice if you wish to place a visible point source somewhere other than the center of the IFU. If you know that you will need a special setup, it is good to note that in the target notes in TSL.
Readout time is about 40 seconds, which is comparable to the amount of time that it takes to make a telescope offset to move your target from the LRS2-B IFU to the LRS2-R IFU. NOTE: the act of moving between LRS2-B and LRS2-R can introduce a few arcseconds of mis-centering, although the telescope operator typically verifies and re-centers the LRS2-R observation manually. Setup images taken with the Acquisition camera will be taken just once final positioning and guiding are achieved but before final focus has been achieved. These images are saved automatically and available on TACC. If, for your science case, final focus must be achieved before your exposure is started this should be noted in your TSL target notes as well.
It is possible, if the requested exposures are short enough, to request that targets be observed with both LRS2-B and LRS2-R in the same trajectory. Usually setup times are only a few minutes to offset between these two positions. The PI should request that the targets be grouped with type "SEQ" and a group name that is unique .
Last updated: Sat, 30 Dec 2023 03:16:02 +0000 stevenj