Creating a Personal Source Catalog

by Gustaaf Van Moorsel last modified Jun 12, 2018 by Lorant Sjouwerman


Personal (re)source catalogs can be created, modified, and removed using the menu strip and icon menu at the top of the tools page. It is convenient to collect (re)sources for a specific project in a separate catalog, especially for convenience during schedule block creation and also, e.g., when sharing with co-I's.

Usually 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 the project name in the left hand side column. You should follow the exercise above and 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 of your target sources, and the examples will help you check and/or modify the content.

Copy/Paste from Existing Catalogs

Regardless of how you create (or how NRAO fills) your source catalog entries, make sure they are correct before you continue with using them in the OPT. The OPT does not use global source properties; when you have modified a source you must use the OPT to reassign the new source separately to every scan that needs it. For this a Bulk Scan Edit has been implemented in the OPT (described later). Check your catalogs before making scans!

Options from the icon menu and menu strip

The icon menu is the line of little icons at the top of the (re)source catalogs in the left hand side column. They have the same functionality as the options from the menu strip (below), although not every menu strip option is represented as they are not used as often. Only basic cut/copy/paste and reordering can be done with this icon menu. Note that the actions selected from the icon menu apply only to editing in the left hand side column. Only valid actions will have an active icon in the menu, i.e., pasting an item may only be performed after copying or cutting the item first -- until then the paste-icon will appear grayed-out. Hovering over an item with your mouse will display a pop-up tool-tip help to remind you of the action attached to the icon, but we also show them for reference below:

Cut Cut (or delete) selected tree item
Page Copy Copy selected tree item
Page Paste Paste selected tree item
Arrow Up Move the selected catalog up in the tree
Arrow Down Move the selected catalog down in the tree

The same icon menu can be found in the RCT; for the OPT we will present additional icons for more options related to ordering scans in the OPT. Remember that these icons act only on the left hand side column items.

The menu strip in the dark blue banner at the top of the page is used for creating new catalogs: FILE - CREATE NEW - CATALOG. It is not advisable to copy the VLA catalog personal catalog in a new personal catalog and add new target sources, but it is useful to copy VLA sources into a new or existing personal catalog. The menu strip options under FILE and EDIT are grayed out with a line through them if that particular option is not valid for the current selection (highlighted item in the catalog tree in the left hand side column). If the action you want to perform shows up as an invalid option (e.g., EDIT - CUT - GROUP to delete your group of sources) this usually means that you are not at the right place in the tree (e.g., not in the group, but in the upper level catalog). The names of the actions are quite self-explanatory, so we only list them for reference in the table; the ones in square brackets only appear when relevant, in particular when a source in a group is selected. A similar list of menu strip options is available in the RCT and OPT, but with options specific to the tools. The menu strip options may act on both items in the left hand side column as well as items in the main editing window.



Adding Sources to Your Personal Catalog

There are three ways to add sources to a personal catalog, each described below. A fourth one is that the OPT gets filled with information from the PST once the TAC has approved observing time for your project. If you find a catalog imported directly from the PST, please carefully check the target source positions before you start using them in the OPT as you may have not entered them in the PST as you want them to appear in the SCT/OPT.

Importing Source Lists, Including Sources Entered in 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 after it has been uploaded by selecting the New Catalog and navigating to the Properties tab. As a reminder, the PST format is/can be found in the relevant section of the PST manual (or in the complete description) in case you decide to make such a file at this stage. You may want to check the details of some sources to verify that the information has ended up correctly in the source property definitions. Verifying it now may save you more trouble later on when creating SBs.

Copying Sources from Existing Catalogs

It is likely that your anticipated calibrator sources (which may not have been included in the proposal cover sheets) are already defined in, e.g., the VLA calibrator source catalog. You can search for calibrator sources 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 - SOURCES, etc. Then select the destination catalog or group and simply paste the copied sources: EDIT - PASTE - SOURCES, etc. You must repeat this action for each catalog or search results table page. Again verify that the source information in your personal source catalog is correct, e.g., by adding additional digits to a source position, prior to assigning source information to scans in the OPT. An example sequence would be as follows:

  • Make sure you have navigated to the SCT.
  • From the top menu strip, select FILE - CREATE NEW -  CATALOG; you can skip this step (and the next step) if the catalog you want to use already exists and is writable (i.e., the catalog name is not in slanted red font), e.g., the catalog automatically
    generated with your project ID.
  • Your new catalog with the default name [New Catalog] appears in the main editing window, in the Properties tab. Change the name of the catalog to something useful to remind you of its purpose.
  • Optionally add the names of coauthors that you want to share the catalog with and who may edit the sources in the catalog.
  • At this stage you can opt to group your sources. This is not necessary, but convenient if you are going to have many sources. If you want to group sources in this catalog, select FILE - CREATE NEW - GROUP, and name your group under the Properties tab.
  • Click to navigate back to the first tab: Sources.
  • Select the VLA source catalog and perform your source search as described previously; use Advanced Search or External Search if necessary.
  • In the source table to the right, in main editing window, check the source(s) you want. If you don't know which source to select, study the details of each before selecting one. If there are more sources than fit on a page you can change the number of sources per page from 25 to 50 or 100, or use multiple actions to select all your sources in subsequent steps.
  • From the top menu strip, select EDIT - COPY - SOURCES.
  • Select your newly named source catalog (or group within it).
  • From the top menu strip, select EDIT - PASTE - SOURCES. If there are groups in the catalog, you will have the option to add them to a group as well. The sources now show up on the right hand side.
  • This can also be achieved by copy/paste of entire groups and/or entire catalogs using the top menu strip options or the menu icons at the top of the (left hand side) source catalog column. Use the fly-over tool-tip help to identify the proper icon for each action.
  • Maybe you want to check the source properties using the Show/Edit icon for each catalog entry. You can also reorganize your sources by adding groups (FILE - CREATE NEW - GROUP) and move your sources around using the column icon menu, or using EDIT in the top menu strip. Unwanted sources can be deleted using Cut.
  • If you are unhappy with the name of the catalog or group you can always rename it by highlighting it and then clicking on the
    Properties tab.

Note that sources do not have to belong to a group. If you have specified groups, sources that do not belong to that group will not show up if you select that group. When there are sources in groups and sources not belonging to a group in the same catalog, you can only see and select a source without a group when you select the entire catalog.

Entering 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 source page consisting of three tabs (or pages) labeled New Source, Images, and Notes. Name your source something convenient to search for at a later point, and fill in the necessary details (see below). You may also care to fill in the origin of your data for your own reference (e.g., PST file name, SIMBAD data base, scooped draft paper, etc.).


Source Positions

There are five different types of positions you can enter: a Simple Position, a Distant source with Proper Motion, a Solar System Body with Table of Polynomials, Solar System Body with Internal Ephemeris, and Solar System Body with Uploaded Ephemeris (Solar Observation is obsolete; use either internal or uploaded ephemeris).

By default the first tab-page uses Simple Position below the source name and aliases. Select a coordinate system (Equatorial, Galactic or Ecliptic) and equinox in which you specify the coordinates and, if you care, also supply a distance (if known). For anything else than the Simple Position use the drop-down menu. The new selection will redraw the position table accordingly with all variables defaulted. You can select a predefined Solar System body name, upload an ephemeris table, 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 not yet fully tested. 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. Delete old or obsolete positions using the tick-box in the upper left of a position table and REMOVE SELECTED POSITIONS. More information, in particular about generating ephemeris files, is given in the Observing Guide under Moving Objects.


Adding Information

In addition to specifying a position, 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 Velocities

In the next table, under Source Positions, Source Velocities can be entered using the Add button (Figure 2.4). 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 REMOVE SELECTED.

Note however, that source velocity information is not used anywhere in the OPT or in the observations, nor is it transferred with the data. Source velocity information entered here is purely a user supplied comment, just like brightness and image links below or distance above. The proper place to enter a source velocity is in the resource of the scan, where Doppler corrections are calculated for the time of observing. How to do this is explained in the "Creating your Resource" section.

Figure 2.4: Adding a source velocity.

Source Brightness

Similar to specifying a source velocity, with ADD you can specify a source flux density and distribution. 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. The actual parameters differ for each flux distribution model. A source brightness model is simply removed with ticking a check box and REMOVE SELECTED.

Images tab

This tab displays the Visibility Chart consisting of the elevation and azimuth of the source as function of LST together with a table of rise and set LST (at 8° elevation) and some other elevation/azimuth and LST properties for your reference. Below are Image Links. It allows you to keep a catalog of image URL links, e.g., to the images in the VLA archive; use ADD or REMOVE SELECTED as many times as desired.

Notes tab

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 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, or whatever you deem useful.


Final check

After all this data entering, make sure you check your catalogs for correctness. It is important that your source positions are correct before creating scans in the OPT and before storing to disk or sharing your catalogs with your collaborators.