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The Position Editor Toolbar provides quick access to the most commonly used features from the menu bar. The buttons have the following action:
- Open - bring up a file selection dialog to load a previously saved image.
- Back - move backwards in image history list
- Forward - move forward in image history list
- Cut levels - bring up a dialog of showing the distribution of pixel values for the displayed image. The minimum and maximum display levels can be set either with the slider or the Auto Set buttons.
- Catalogs - opens the catalog navigator for defining and executing custom guide star and image server queries. It is also useful for seeing the detailed results.
- Images - queries the the default image server using the base coordinates of the observation selected in the Program Editor. If no default is set then a Image Server dialog (below) queries the user to select a server. The default can then be changed by selecting a new server from Catalog -> Image Servers in the menu bar (the current default is marked with a black dot) or by selecting an image server with the Catalog Navigator and pressing the Store Settings button (the icon of the default is shaded yellow).
- Manual GS - opens the Guide Star Selection dialog (below) for doing quick guide star searches. The coordinates for the search is the base position of the observation selected in the Program Editor. Likewise the Instrument is set using the instrument component of the selected observation in the Program Editor. The Guide Star Type and the Catalog is remembered from the last query. The combination of the instrument and guide star type determine the minimum and maximum radii and the limiting magnitude for the query. Custom queries can be constructed using the catalog navigator.
- Auto GS - initiates a UCAC3 guide star query and automatically selects the brightest allowed guide star in the patrol field. This applies to the Peripheral and On-Instrument wavefront sensors; selection of GSAOI/GeMS guide stars will be described elsewhere. The allowed WFS patrol field is the union of the patrol fields for all offset positions where the WFS is set to guide (not freeze or park). This field is shown by the green line in the PE. The magnitude limits for the guide star candidates are determined by the WFS and the observing conditions constraints. If no guide stars that match the conditions constraints are found, but guide stars are available for better conditions, then the following dialog appears:
Clicking the Manual Search button will open the Manual GS dialog. Note that making the conditions constraints better may require approval from the appropriate Head of Science Operations.
If a position angle of PA+/-180 degrees is acceptable for your observations, then is check the box labeled "Allow +/-180 degree change for guide star selection" in the GMOS component.
With this option permitted the guide star selection will automatically change the PA if a brighter guide star is available at PA +/- 180 degrees. If this options is not selected and a brighter guide star is found at PA +/- 180 degrees, then will ask if the PA should be changed and this star selected.
If you prefer that the OT not ask this question, select the box labeled "Don't ask about alternative options again." This will affect all sulbsequent automatic guide star queries in all programs in the OT. To re-enable this prompt choose Preferences from the Edit menu in the Science Program Editor and then check "Alternative guide star options."
If no guide star is available at the current PA or PA+/-180 and PA is not important for your observations, then you should check if a guide star is available at another PA. All guide stars that are usable with the current conditions constraints are marked with red circles on the Position Editor and can be quickly selected with the + GMOS OIWFS PE button.