Daily Image
06-10-2009
X-shooter last minute repair
| Submitter: | Eddy Elswijk |
| Description: | Last week, the only moving part in the X-shooter Near InfraRed (NIR) Spectrograph, the slit wheel, suddenly stopped functioning. The problem was located inside the cryogenic part of the NIR vacuum vessel. Repair was urgent, because on October 1st X-shooter will be made available to the community for science observations. A repair team consisting of Eddy Elswijk and Ramon Navarro was sent to Paranal immediately. The cryogenic NIR slit wheel did not rotate with the motor, which is located outside the vacuum. A broken bellows inside the vacuum vessel was the cause of the malfunction. The bellows allows for misalignment between the rotation axis in the cold optics box and the motor rotation axis outside the cryostat. After some investigation, the problem was identified and repaired, preventing future problems. The image shows X-shooter mounted at the Cassegrain focus of VLT KEUYEN - UT2. Visible on the image are the white mirror Cell, supporting the 8.2m VLT main mirror, with X-shooter attached to it. The round NIR liquid Nitrogen tank is clearly visible as the lowest element of the structure, while the cylindrical vacuum wall lies on the floor. The blue structures on the left and right of the image support both the telescope and the Nasmyth platforms. X-shooter is a "seeing-limited" instrument, consisting of three spectrographs, covering the entire range from 300nm to 2500nm at medium resolution (R= 6000-10000) in a single shot. The Dutch contribution is the NIR spectrograph and is a combined effort of the University of Amsterdam, Radboud University Nijmegen and NOVA-ASTRON. Other European partners in the X-shooter project are France, Italy, Denmark, and ESO. |
| Copyright: | © NOVA-ASTRON - Ramon Navarro |
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