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Home > Astronomy > Telescope Operator Notes > Working with LAOT


LAOT is the Leiden Adaptive Optics Telescope. It is a setup in GHRIL to test novel coronograph and wavefront sensing concepts. It was first used on April 25-26th 2015



  • USER> AGSEL (any - no autoguider used)
  • USER> FOCUS 97.0 (April 2015) It is not very sensitive to focus

Check that the position of the NASMYTH TURRET is in GHRIL position.

Telescope focus:
Change the focus in large steps (e.g. 0.5mm) and see if the image gets better or worse. The observers will do this.

Rotator center:
LAOT doesn't use a derotator so no rotator centre can be found and no 7-star calibrate is done. The Turntable will say STOPPED.

LAOT doesn't use an autoguider.


Sky Flats: If required, they might need to be done with a lot of light well before sunset. They can be done at zenith in this case.

Acquisition: The FOV of the detector is 25" so it might be necessary to do a spiral search to find the target.

Movement of target using XY HANDSET keys:

       |      |
       |      |
       |  <-- |
       |      |
|  ^   |      |  |   |
|  |   |      |  |   |
|  |   | -->  | \/   |
|      |      |      |

Changing between ACAM and LAOT: Since ACAM is usually mounted at Cass, it's possible to use both instruments on one night by changing the focal station.

  • USER> EL 90   (the telescope must be at zenith before moving the Nasmyth flat)
  • close mirror petals
  • press GHRIL or CASS as required, on the Nasmyth Turret control on the engineering console
  • USER> SHOW FOCAL   (while the mirror is moving it will say "unknown optical configuration" and it will give the correct focal station when it is in position, which takes about 3 minutes)
  • USER> STATION cass/ghril_norot
  • USER> AGSELECT cassegrain (for ACAM, none needed for LAOT)
  • USER> FOCUS XXX   (as required)
  • USER> CAL LAST   (needed after change of station)
  • open petals


In April 2015, the BESR filter was used, since LAOT's own filters were not all suitable. It was kept mounted in an ACAM filter and then placed on the optical bench in a homemade mount, which seemed to work fine.

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Last modified: 27 April 2015