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Maybe one general thing to note is that there were relative many (small) problems that were related to the introduction of new things (new TCS, FIES, new data acquisition computers and software). Currently, we are trying to develop procedures to minimise any possible problems when introducing new things at the telescope. Below are listed those faults for which 2 or more hours were lost.
This was a problem with centring a star on the slit using ALFOSC. After some time it was realized that the observers were trying to follow old instructions and they were pointed to the correct instructions. A careful check was made of all the instructions on the web and in printed form at the telescope.
Intermittent problems with the tracking were reported. With the help of the more extensive and detailed logging now available it was quickly realized that the problem was likely caused by the brushes in one of the motors failing. Checking in the day time did not show any problems and it was not clear which of the motors had the problem. As changing the brushes is a fairly difficult task which takes a significant amount of time it was decided to change the brushes in the motor where the brushes had been changed the longest time ago. Further testing after worse did not show any problems either but during the next night again problems occurred, now causing even more loss of observing time. The next day the problems with the other motor were now actually seen during testing, and the brushes in that motor were replaced after which the problems disappeared.
Already for some time we have plans to make access to the motors easier such that changing the brushes takes much less time but that has been postponed because of the absence of Peter Brandt. We now hope to make these modifications in the near future such that any maintenance or repair work will be easier and take less time.
Observations were made with FIES using the simultaneous-ThAr calibration mode. It took some time before the observer noted that the lamp did not work any more. As this was also the first time that there was a problem with this lamp it took some time to replace it.
We are currently working on a testing procedure that will check various things in FIES (including the calibration lamp) in the daytime and notifies staff if there is a problem.
The observers followed properly the procedures to centre a star on the slit and take a spectrum, but did not get the results that they expected. In the end they decided to user a different slit with which things worked as expected. It took some time to find out that this was due to errors in making the set-up. The main error was that the specific set-up was not checked, where it was assumed that a previous set-up would still be valid. On top of that, in the set-up the specific name of the slit was given incorrectly (marked as being a horizontal instead of a vertical slit) which made things worse.
Thomas Augusteijn 2008-01-11