Faint Object Red Spectrograph (FORS)

AAT Instrument - FORS is a decommissioned instrument and is no longer offered or supported at the AAT. The following information is provided for historical completeness.

In Brief FORS is a fixed format spectrograph which provides low resolution coverage between 5300 - 11000 Å. Simultaneous observations can be made on FORS and the RGO Spectrograph with a dichroic beam splitter to provide full optical coverage.
Instrument Scientist No Instrument Scientist at present. Contact Head of Astronomy for information.
Manual AAO UM-23.1 FORS Users' Manual, Couch, W. J., 1989. Available in hardcopy only.
There is also an entry in the AAO Observer's Guide.
Dectector 576 x 385 uncoated GEC CCD with 22 um sq pixels.
Focal Station mounted at Cassegrain, with f/8 top end
Image Scale 1 arcsec per pixel (unbinned)
Spectral Resolution R=300 at 6000 A with 2 arcsec slit.
Filters Dichroic beam splitter gives 5300 - 10200 Å
GG495 gives 5200 - 9600 Å
OG530 gives 5300 - 10200 Å
RG630 gives 6300 - 11000 Å
Non-standard Modes Can be used with polarimeter, in time series mode, and with FOCAP for multi-object observations.
Sensitivity AB6600 = 17.5 gives 1 electron/s/Å. NOTE that FORS is ~2 times less efficient than the RGO+270R+Tek option, and should only be used if wavelength coverage is critical.
*Spectral Resolution R measured as lambda/delta_lambda, delta_lambda = FWHM unresolved line, usually 2 pixels.