Set up scans for each source in the Source List

From the Edit Lists Page select from the bottom panel:

New entry --> Source List

enter scan name: if the scan name is the same as a VLA calibrator the source name and position will be added automatically

Insert

Dismiss

Edit scan details by double-clicking on the scan name in the Source List. There are several pages of details to be set up for a scan. The first page to complete is the Source Page. To move to the other pages use PgUp or PgDn. You may also select the other pages from the menu to the left of PgUp. When working on a particular page you may also step from one scan in the Source List to the next using SrcUp and SrcDn.

On the Source Page complete the following fields (see also the description of the Source Page for the User Defaults List):

Source Name

Defaults: select either User Default or NRAO Default. This may set up some of the following fields automatically

Qualifier: numeric, optional

Comment: optional

Observing Mode: select observing mode such as Standard Interferometer

Offset Mode: select offset mode such as Fast Switching, if needed

Integration Time: set integration time required, if it has not been set by the User/NRAO Default

to apply a recent reference pointing solution select Ref. point = Yes. Important at K and Q bands. NOTE: make sure you have carried out a reference pointing scan before trying to apply a solution. Do NOT select Ref. point = Yes for a scan for which Observing Mode is set to Det. primary ref pntng or equivalent

if the Source Name is in the VLA Calibrator Manual set Calibrator = Yes and the position will be completed automatically; otherwise set Calibrator = No

Right Ascension, Declination: enter the source position, if the source is not in the VLA Calibrator Manual. The epoch with the asterisk beside it will be the position written to the observe file; make sure this is the same epoch as that specified under Starting Conditions. NOTE: use either B1950 or J2000 for all source positions in your observe file, but not both; although the VLA online system will cope with mixed epochs, the data reduction software may not

File: enter names of IF or ROT files, if required

On the Scheduling Page complete the following fields (see also the description of the Scheduling Page for the User Defaults List):

enter time for either the total duration of the scan (includes slew time and scan set up times), or the dwell time of the scan (slew time and set up times will be added by JObserve), or the Stop LST of the scan

Wrap: leave blank

Plunge: determines whether the VLA antennas are allowed to have elevations greater than 90 degrees ("go over the top"); usually leave this blank, unless you are observing at low frequencies and know what you're doing

The LO Options Page should be set up by the User Default or NRAO Default. It can be changed in scans in the Source List or Observe List if necessary (see also the description of the LO Options Page for the User Defaults List).

The Freq Calculations Page should be set up by the User Default or NRAO Default. It can be changed in scans in the Source List or Observe List if necessary (see also the description of the Freq Calculations Page for the User Defaults List).

If Spectral Line has been selected in the Starting Conditions, you will also see the Correlator Page. It should be set up by the User Default or NRAO Default, but it can be changed in scans in the Source List or Observe List if necessary (see also the description of the Correlator Page for the User Defaults List).

If Planet/Solar Motion has been selected in the Starting Conditions you will also see the Planet Motion Page, but see comments under Starting Conditions on using JObserve for planetary and solar observing.

If Fast Switching has been selected on the Source Page, you will also see the Fast Switch Page. Complete the following fields (see also the description of the Fast Switch Page for the User Defaults List):

IF for Beam Size: the beam size determines when the VLA online system deems an antenna to be "on source." Leave at the default value unless you are observing in 4P mode, in which case select IF B (although it is unlikely you will use Fast Switching in 4P mode)

RA: enter RA of offset position

DEC: enter Dec of offset position

CalCode: enter the calibrator code if the source at the offset position is a calibrator

Primary: enter time to spend on primary source position specified on the Source Page (must be a multiple of 10 sec)

Secondary: enter time to spend on secondary source specified on the Fast Switch Page (must be a multiple of 10 sec)

NOTE: Durations specified on the Fast Switch Page must include sufficient move time to slew between positions. The VLA antennas slew at a rate of 20 degrees/minute in elevation and 40 degrees/minute in azimuth. Add 6 seconds to the estimated slew time to allow for settling of the antennas. For spectral line observations the Primary source is used for the Doppler tracking, so the Primary should be your target source and the Secondary should be your calibrator

A fast switching scan will typically comprise several fast switching cycles between the primary and secondary source positions. The Dwell time on the Scheduling Page specifies the total length of the fast switching scan (excluding initial slew and scan set-up times), and should be made to be long enough to include the number of cycles you require.

Small mosaic fields can be specified as separate sources with individual pointing centers. However, for large fields it can be useful to use Mosaic mode. If Mosaic mode has been selected on the Source Page, you will also see the Raster Page. A mosaic raster begins at the position specified on the Source Page, and continues in a straight line for the number of samples specified and in the direction specified. Complete the following fields (see also the description of the Raster Page for the User Defaults List):

IF for Beam Size: enter IF to use when calculating Spacing of samples

Azimuth: leave blank

Elevation: leave blank

Position Angle: specify PA of raster (0=increase in RA, 90=increase in Dec)

Time per sample: includes move time between points

Number of Samples: number of samples per raster

Spacing: spacing of samples per beam (2 = Nyquist)

NOTE: a separate scan is needed for each row of a mosaic grid

If Holography mode has been selected on the Source Page, you will also see the Raster Page. Complete the following fields (see also the description of the Raster Page for the User Defaults List):

IF for Beam Size: enter IF to use when calculating Spacing of samples

Azimuth: specify Az offset of starting position of raster, in grid units

Elevation: specify El offset of starting position of raster, in grid units

Position Angle: specify PA of raster (0=increase in Az, 90=increase in El)

Time per sample: includes move time between points

Number of Samples: number of samples per raster

Spacing: spacing of samples per beam (2 = Nyquist)

NOTE: a separate scan is needed for each row of a holography grid

To return to the Edit Lists Page at any time select Done.