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Field Setup

In the Field Setup page the user is asked to enter various sourcesparameters, such as the coordinates and velocity. Thevelocity can be specified using the optical,radio or relativistic conventions. Most of the source parameters canbe completed using the Resolve button once the source name hasbeen entered. A window will display the server name that returned thequery results and warn you to check the returned parameters!

The allowed values of the velocity reference frame are: lsr, lsrk,bar, hel, topo . When changing the source velocity reference system, adialogue box will become visible with a warning that no velocityconversion was performed. It is the users responsibility to ensurethat the entered information is correct!

The telescope pointing parameters are specified using Target Type . This allows you to define either Multiple single point fields or 1 rectangular mapping area . Both can be defined in theForms editor or by using the Visual Spatial Editor. The default Target Type of each source is Multiple single point fields . To define a rectangular field, fillin the fields p length , q length , Position Angle and Spacing or use the Visual Spatial Editor. The Spacing caneither be specified in angular units or in fraction of the primarybeam; the default spacing is the Nyquist value (half he diameter ofthe primary beam). The Position Angle is measured in theastronomical sense, positive from the positive x-axiscounterclockwise. Once defined, the rectangular area will be tiledwith a mosaic pattern according to the Spacing parameter; thiscan be viewed in the Visual Spatial Editor.

Depending on which Target Type has been chosen, the last panelon the page is either Field Centre Coordinates or Rectangular . This lists either the positions of each pointingcentre of the parameters of the rectangular area. Note thatcoordinates can be provided either as an offset relative to the sourcecoordinates in the Source panel (fields Offset [RA] and Offset [Dec] ), or as absolute coordinate (fields RA and Dec ).

Additional sources can be entered using the Add Source button. Note that this can only be done if the Target Type isset to Multiple single point fields ! Therefore, if you wish todefine a rectangular mapping area, you can only enter one source perScience Goal. Delete Source and Delete All Sources do whatyou expect. The Field Setup form for a single point field is displayedin Figure  6.6 .

A list of sources can be uploaded using Load from File... ; this will replace any previously defined sources.The format of the ASCII source list is displayed inFigure  6.7 . For each new source, a new field informationform is created that can be selected using the tabs at the top.

Figure 6.6: The Science Goal Field Setup Form with three sources defined. The selected source has been assigned a single telescope pointing position.
\resizebox{10cm}{!}{\includegraphics{images/FieldSetup.eps}}

Figure 6.7: The example of a source list that can be loaded via the Science Goals.
\resizebox{10cm}{!}{\includegraphics{images/ScienceGoalTargetList.eps}}



Subsections
next up previous contents index
Next: Using an Ephemeris Up: Adding Phase-1 Science Goals Previous: General   Contents   Index
The ALMA OT Team, 2011 May 20