In General No guide stars, bad pointing The TCS disconnects Data Acquisition problems In General Most of the faults can be cleared by typing: SYS> startobssys Try to avoid 'shutdownobssys' followed by 'startobssys' as in most cases such a drastic measure isn't needed. SYS> shutdownobssys should only be used to shutdown the observing system at the end of the night. If a sub-system (DAS, TCS or Autoguider) is corrupted 'shutdownobssys' wont help. First the sub-system has to be brought back, then SYS> startobssys will re-establish contact between the observing system and the sub-systems. No guide stars, bad pointing First repeat ZEROSET at zenith in engineering mode followed by: USER> CAL LAST Check pointing with a pointing grid star and the TV: USER> GOCAT pointing-star If the star comes up within 15 arcsec from the center, the pointing is fine. If no bright star is seen may be the last pointing solution is wrong or got corrupted somehow. Before calling for help try this: Repeat ZEROSET at zenith in engineering mode followed by: USER> CAL DEFAULT and check again the pointing with a pointing grid star and the TV. To recalibrate the telescope pointing follow this commands. The TCS disconnects Most likely the TCS TELD task has died. To restart go to the xterminal were the TCS user interface and info display are running. Open a LAT terminal and log on to lpas2 (see label on screen for uid and passwd). From the main menu then select 'options' and 'teld' from the options menu, afterwards SYS> startobssys will re-establish contact between the observing system and the TCS. Data acquisition problems By Data acquisition we mean the management of an exposure, reading of data from the CCDs and saving to disk. This may fail in one of several stages, for example: Run, Finish, Abort or Re-time commands are not successful Run process stops after CCD clearing Run spontaneously aborts during readout or transfer to disk Transfer to disk does not complete to 100% Data on disk is corrupted (e.g. torn frames) These may or may not be accompanied by a pop-up error box/alarm. If the error pop-up mentions the (ultra)DAS or "reset the camera", and you cannot continue observing, then the following procedure is recommended (pink window): SYS>dasreset IDS            (i.e. startobssys is unnecessary) When this completes, try a new Run and see if the above fault recurs. If it does, then a lower-level reset of the CCD controller may necessary and you might need to move the telescope to zenith. Power cycle the SDSU CCD controller, attached to IDS, followed by: SYS>dasreset IDS If you are unsure about any of the recovery procedures or if they fail, call for WHT TO, SA or DT/IO support.