The Oxford SWIFT Spectrograph

SWIFT Commissioning

SWIFT was commissioned at the 200 inch Hale telescope on Palomar Mountain in October 2008 and December 2008. The December observing run was combined with some science observing. Although the instrument could be fully commissioned, only a few on-sky tests could be carried out, as weather was very poor during both observing runs. The weather statistics for the first three runs, in October & December 2008, and Jan 2009, recovered from the observing logs, are shown below.

Pretty Pictures and Movies

A time-lapse movie of the first installation of SWIFT at the 200 inch Cassegrain focus (together with the PALMAO Adaptive Optics system) can be found here. (warning 104MB!) (courtesy Scott Kardel, Palomar Observatory.

Here is nice photo (courtesy Fraser Clarke) of SWIFT at the 200 inch.

Technical

Below are some technical data from the October and December 2008 commissioning runs. It shows some of the first alignments of SWIFT.

The through focus scan carried out during commissioning to determine the best instrument focus is shown below.

The first alignment of the instrument pupil with the AO system pupil (at the 235 mas spaxel scale) is depicted in this reconstructed image (made using the pupil imaging optics). Note that the step between the two halves of the pupil is not real, it is the result of improper bias subtraction on the CCDs, which have significantly different offset levels.

During the December observing run, SWIFT was commissioned for LGS operations. There was significant improvement in the PSF width, even at the SWIFT wavelengths, although the atmospheric seeing was less than optimal for adaptive optics observations. The image on the left (taken with the imaging camera on SWIFT, not the spectrograph) is with the LGS turned off, while the one on the right is with the LGS turned on. Radial profile plots are shown alongside. The substantial improvement in image FWHM is easily seen.