Creating a Personal Source Catalog

There are three obvious ways to add sources to your personal catalog, each described below. A fourth one is that the OPT gets filled with information from the PST once the PSC has approved observing time for your project, but this is currently not completely functional. If you find a catalog imported directly from the PST, please carefully check the target source positions and velocities (and velocity definitions and reference frames) before you start using them in the OPT.

Importing source lists used with the PST

If you or a co-investigator uploaded a source list with your proposal in the PST, and this source list has not been transferred from the PST (or you prefer to delete that one), you should be able to get a head-start by uploading the same source list to the OPT. Use FILE - IMPORT... to communicate with a dialog box. Choose PST as input format and name your source catalog. As a reminder, the PST format is/can be found in Section 4.4.4 of the PST manual (e.g., from the NRAO proposal portal documentation link (https://my.nrao.edu/nrao-2.0/PSTMANUAL/PSTMANUAL.html) in case you decide to make such a file at this stage. You may want to check the details of some sources to convince yourself that the information has ended up correctly in the source property definitions, in particular the velocity reference frame and definition. Checking it now may save you more trouble downstream when scheduling SBs.

Copy/paste from existing catalogs

It is likely that your anticipated calibrator sources are already defined in, e.g., the VLA calibrator source catalog. You can search for your named, or a nearby, calibrator source using the search tool described earlier in this chapter. In the catalog (or group) or in the search results you can select one or more sources you desire to add to your personal catalog by ticking the check-box(es) in front of the source name and editing icon using the top menu strip EDIT - COPY - COPY SOURCES, etc. Then select the destination catalog or group and simply paste the copied sources: EDIT - PASTE - PASTE SOURCES, etc. You have to redo this action for each catalog or search results table page. Again convince yourself that the source information in your personal source catalog is correct, e.g., by adding velocity information for spectral line observations, before starting to assign source information to scans in the OPT.

Enter source information from scratch

If you do not use the PST upload file and your source does not appear in any of the existing catalogs, you would create a new source in a source catalog (or group) after selecting (or creating) the catalog or group you want to place the source in: (FILE - CREATE NEW - CATALOG/GROUP,) FILE - CREATE NEW - SOURCE. You will be presented with a blank-slate source page consisting of three tabs (or pages) labeled "New Source", "Image Links" and "Notes". Name your source, perhaps something convenient to search for at a later point. Maybe you also care to fill out the origin of your data for your own reference, possibly useful for later (PST file name, SIMBAD data base, scooped draft paper, etc.).

In addition to specifying a position and possible velocity needed to track a source, some extra reference information may be specified for this catalog entry. These items however are not necessary for the observation and are provided for your own reference.

Source Brightness:

With FILE - CREATE NEW - SOURCE BRIGHTNESS you are asked which type of brightness distribution you want to add to your source properties. For unresolved (point-like) sources you would probably choose type Point, and fill out the Flux Density at some Frequency Range. A slightly resolved source perhaps would be better described by a Gaussian model with a Major Axis and Minor Axis Diameter at some Position Angle. Planets also use the Limb Darkening property of the Disk models. You can specify more than one brightness model for a source, or provide a FITS image or clean-components model file.

Image Links:

If you want to keep a catalog of image URL links, e.g., to the images in the VLA archive, use FILE - CREATE NEW - SOURCE IMAGE LINK as many times as desired.

Notes:

This tab-page is where you can collect all other information you wish to attach to this source. For example, for a target source you can remind yourself of the nearby calibrators you have found to be useful at some frequency, a reference to a paper mentioning an alternate position or a source property, or anything else you want to note. Click the blue expand button or New Note to add information to the Notes field. You can, e.g., also add links to papers or any other URLs for that matter. User defined values can be added at the bottom, e.g., the UV-range you determined to be proper for a point source calibration model, the color of its eyes, etc; whatever you deem useful.

When you are happy with your (re)sources, at any time you can save the changes you made. At this point it would be a good time: FILE - SAVE ALL.

It is possible that NRAO has already been able to retrieve your sources from what you specified in your proposal. If this is the case you will find these in a source catalog, labeled with an editable legacy ID name, in the column at the left. However, you should follow the examples below to get a feel for what is in your source catalog. You will want to check the entries in your source catalog, especially the accuracy of positions and the velocity specifications of your target sources, and the examples will help you check and/or modify the content.

The icon menu between the source search tool and the source catalog list in the left hand side column was introduced in the previous chapter. Here the menu icons behave exactly the same as in the RCT. The fly-over help tool-tip will help remind you of their actions.

Also introduced in the previous chapter was the use of the options in the menu strip (e.g., FILE - CREATE NEW - CATALOG). The menu strip options in the SCT are slightly different, again with names that are quite self-explanatory about their actions in the table.

Below we will comment on each of the choices for Source Position(s), Source Velocity(ies), Source Image Link(s), and Source Brightness.

There are three different types of positions you can enter: a simple position, a sequence of positions including motion terms and time ranges, and an ephemeris table. The default, in the first tab-page below the source name and aliases, is "simple position". Select a coordinate system (and equinox) in which you specify the coordinates and if you care, also supply distance (if known) and the uncertainties. For anything else than the default ("simple position") use FILE - CREATE NEW - SOURCE POSITION. The dialog box will ask you which type of position you require, and a new selection will redraw the position table accordingly with all variables defaulted. You can upload an ephemeris table (click the link for an example of the ephemeris table format), or you can specify the position and some motion terms valid for some time range. Motion terms are entered as polynomials in time [display]\rm position\ at\ Reference\ Time\ in\ Equinox + value(1) \times time + value(2) \times time^2 + value(3) \times time^3, etc [/display]  Press the [+] for each extra motion term, enter the value and choose the order of the polynomial in time. The motion term units and uncertainty will help recalculating the position (and error) at the time of observations, though this is currently (early 2009) not yet implemented. Leave the motion terms at zero if the source is considered not to move in the specified time interval. If you need another position and/or different motion terms for another time interval, simply add another position to the previous one using the same FILE - CREATE NEW - SOURCE POSITION. Delete old or obsolete positions using the tick-box in the upper left of a position table and EDIT - CUT - CUT SOURCE POSITIONS.

In the next table under the source position, a source velocity can be entered using FILE - CREATE NEW - SOURCE VELOCITY (Figure 3.4). Enter the value and select a rest frame and rest frame convention. Just like a position you can add more than one velocity, but valid for another frequency range. Removing old or obsolete velocities is also a very similar procedure: tick the unwanted velocity and use EDIT - CUT - CUT SOURCE VELOCITIES.

Figure 3.4: Adding a source velocity.