The 'new' bundle C (the refurbished original bundle `A') was received at NOT and has been pulled from the hole under the telescope to the FIES spectrograph. All 4 fibers transmitted healthy amounts of light after the installation. The new bundle has been installed and tested, and is the default bundle as of January 2010. The 4th fiber allows for simultaneous sky background observations, but this option still needs to be tested in practise.
The new fiberhead was aligned with the telescope using a laser mounted in the adapter V-block. An XY-slide was prepared and mounted on the adapter plate to make alignment of the fibers easier. With the new bundle C the XY slide was repositioned to get maximum counts in all fibers. The alignment of the arm positions of the calibration fibers was determined for the different fibers. The position of the calibration fibers at the adapter was realigned and we now require only short exposures times for calibration exposures for all science fibers.
The current FIES pickoff mirror has stains and is likely not optimally reflective and probably needs to be replaced. From measurements it was found that that the mirror of the first single-pass collimator of the instrument has a very poor reflectivity of only 82% while the mirror of the second double-pass collimator has a somewhat better reflectivity of 90%. We are investigating the possibility to recoat these mirrors.
It was checked if the edges of the cross-disperser causes the extended wings in the X-direction of the point-spread-function of the instrument by masking off the edges, but this did not give any difference.
Thomas Augusteijn 2010-05-27