Only the blue side can be windowed. The default spectral region is available. The red side can not be windowed.
The OA can focus the telescope using the MIRA script.
Optimal exposure times for imaging flat fields and spectroscopic wavelength calibrations may differ between normal LRIS observing and polarimetry mode. The following tables provide estimated exposure times for the RED side.
Estimated exposure times for spectroscopic-mode calibrations
|using 1.0" slit||using 1.5" slit|
|Hg+Kr*||3 sec||2 sec|
|Neon||3 sec||2 sec|
|Argon||4 sec||3 sec|
|Internal Halogen lamp||18 sec||12 sec|
*be sure to let this lamp warm up before taking the exposure!
Estimated exposure times for imaging-mode calibrations using dome lamps
These lists are derived from the following papers, which can be consulted for further details:
Another source of useful polarized standards can be found at:
You will also possibly need to take spectrophotometric flux standards and/or imaging photometric standards
Note on calibrations with polarizing elements in (the HNP'B UV/optical Polaroid and the IR800 IR polarizer); in some wave plate positions all of the light will be in one beam, so don't let yourself be fooled into doubling your exposure times and saturating the images at those angles!