Catalog Assistant Help

The PIT includes a catalog assistant tool which has been designed to help search for wavefront sensor stars. A search can be canceled at any time by clicking the 'Cancel' button at the bottom of of the screen.

  1. Select a server and search algorithm in the Criteria section.
    Different algorithms are available e.g. for peripheral wavefront sensors (PWFS), on-instrument wavefront sensors (OIWFS) and facility adaptive optics wavefront sensors (AOWFS). See the relevant instrument "Performance and Use" web pages for the recommended WFS for each instrument mode.
    Guide star catalog servers are available at CDS, CADC, and ESO. Generally you will get the best performance by selecting the geographically closest server.
    If the guide star is the same as the target, frequently the case for AO observations, then select either the Target is NICI AO Guide Star algorithm if using NICI or the Target is AOWFS Guide Star algorithm if using Altair. 
  2. Select all or specific science targets from the Target Selection list to have guide stars found for those objects. Individual targets may be selected/deselected using the 'Included?' checkbox.  Unselect all targets with the 'None' button.
  3. Activate the search by clicking on the magnifying glass icon. The green LED will flash whilst the search is in progress. You can stop the search by clicking on the stop sign icon. The status for each target will change from pending to complete when finished.
    Upon completion the search results for each target are listed at the bottom of the page. The star name, coordinates, magnitude and other information are shown for each star.
    Generally the algorithm will select the brightest stars available within acceptable magnitude limits in the WFS patrol field. Note that the PWFS may partially vignette the widest fields (e.g. NIRI f/6) - see the NIRI pages for more details. You can override the algorithm, and view all potential stars from the chosen catalog that are in the patrol field, by selecting the target and using the 'Override?' checkbox. You may then choose alternative, or additional, stars. Be wary of stars with V magnitudes fainter than 15 (or 13 if chopping) since these are usable only in the best conditions.
  4. Complete the WFS star search by clicking on the Ok button. The selected WFS stars (name, co-ordinates and brightness) will be added to each observation in the program information tree.

The catalog search can fail because there are no cataloged stars available within the WFS patrol field. If you know of suitable WFS star(s), they may be added manually (see the Help with Observations page). Some objects may have no suitable stars and cannot be observed.

WFS stars should not be added for non-sidereal objects or target of opportunity observations at this time.