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The long hoses for the PTR have been installed, and the PTR works now permanently also when the instrument is mounted on the telescope. No problems have been encountered with the hoses as the telescope and rotators move during the night. Also, test observations has show no deterioration of the image quality due to vibrations from the PTR transmitted to the instrument down to a best seeing of 0.5 arcsec.

With the PTR permanently installed the detector is kept at a more stable temperature during the night, which means a more stable dark level. Also, it is much less vulnerable to spilling of LN2 then before.

Thomas Augusteijn 2003-05-08