If you will be using the NRAO default settings for all your scans, there is no need to set up your own user defaults. However, if you will be consistently using a different setting for some of the parameters, such as the integration time, or are observing in spectral line mode, it can be useful to set up your own template. This section describes how to set up a user default.
From the Edit Lists Page select from the bottom panel:
New entry
You will see the New Scan window:
select User Default List from the menu of listsenter scan name for your frequency set-up
Insert
Dismiss
Edit scan details by double-clicking on the scan name in the User Default List. There are several pages of details to be set up. 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 User Default List to the next using SrcUp
and SrcDn.
On the Source Page complete the following fields:
Qualifier: numeric, optional
Comment: optional
Observing Mode: select observing mode such as Standard
Interferometer
Offset Mode: select offset mode such as Fast Switching
or Mosaic, if needed
Defaults: some of the settings you need may be available in
one of the NRAO default set-ups; if this is the case, select the relevant
NRAO default under Defaults
to apply a recent reference pointing solution to all the scans that
will be using this frequency set-up select Ref. point = Yes.
Note that you should NOT select Ref. point = Yes for a scan for
which Observing Mode is set to Det. primary ref pntng
or equivalent
Calibrator = No
Right Ascension, Declination: should all be zero
Band: select observing band
Bandw: select bandwidth required
Integration Time: set integration time required, if it has
not been set by the NRAO Default, or if you require an integration time
different from the NRAO Default
File: enter names of IF or ROT files, if required
For more details on the Source Page please see the JObserve
Online Documentation.
Using either PgDn or the menu on the bottom panel,
go to the Scheduling Page:
On the Scheduling Page complete the following fields:
For more details on the Scheduling Page please see the JObserve
Online Documentation.
Using either PgDn or the menu on the bottom panel, go to the
LO Options Page. The following example is for a spectral line
observation of the 22 GHz H2O line:
On the LO Options Page, if you are not using an NRAO Default,
complete the following fields:
Frequency/Velocity option: if you are Doppler tracking and
have selected either radio velocity or optical velocity
under the this option then you will also need to set the following:
Apparent sky frequency: specify whether the sky frequency
should be at the band center or band edge
Rest frame for DOPSET: select the relevant rest frame for Doppler
tracking
If you will be applying Doppler tracking online, also complete:
If JObserve complains that it cannot tune the LOs to match your requested
frequency/velocity combination, it may be that the bandwidth you have
selected is too broad to fit into the 50 MHz bandpass of the VLA when
Doppler tracking is included. Try narrowing the bandwidth to see if
this is the problem. If it is, try a nearby L6 setting from the 2-4 GHz
LO menu. For further details on the VLA local oscillator chain please see
the Spectral
Line Users Guide
For more details on the LO Options Page please see the JObserve
Online Documentation.
Using either PgDn or the menu on the bottom panel, go to
the Freq Calculations Page. The following example is for an
observation of the 22 GHz H2O line, Doppler tracked to a velocity of
10 km/s:
On the Freq Calculations Page, if you are not using an
NRAO Default, complete the following fields:
Bw: should be as Bandw on the Source Page
IF Filter: bandwidth of IF filter
If you will be applying Doppler tracking online:
If you are specifying the sky frequency directly rather
than applying Doppler tracking online:
Freq Vel: you may specify directly the Fluke frequencies
under Freq Vel, or let JObserve calculate them for you
Front End LO: should be calculated by JObserve
2-4 GHz LO: should be calculated by JObserve
to fix a value in one of the fields select the button directly beneath it
For more details on the Freq Calculations Page please see the JObserve
Online Documentation.
If Spectral Line has been selected in the Starting
Conditions, you will also see the Correlator Page (example
shown is for the NRAO Default continuum):
On the Correlator Page complete the following fields:
Integration Time: should be as set on the Source
Page. NOTE: if you are observing in Spectral
Line mode the Integration Time you can use
may be limited by the total data rate. Please see the note here
for acceptable combinations of Integration Time and
Correlator Mode/Channel Count
Array Processor mode
Channel Count: usually all
Selection Starting: beginning channel number to save, if
Channel Count is not all
For more details on the Correlator Page please see the JObserve
Online Documentation.
If Planet/Solar Motion has been selected in the Starting
Conditions you will also see the Planet Motion Page, but
see the 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:
All entries on the Fast Switch Page should be left blank for
scans in the User Default List.
For more details on the Fast Switch Page please see the JObserve
Online Documentation.
If Mosaic or Holography mode has been selected on the
Source Page, you will also see the Raster Page:
All entries on the Raster Page should be left blank for scans
in the User Default List.
For more details on the Raster Page please see the JObserve
Online Documentation.
Source Name: leave blank
Duration or Dwell: durations specify the total time
for a scan (including slew time and the 20 second scan set up time),
dwell times specify the time on source after the telescopes have slewed
to it. If you intend to have the same duration or dwell time for all
scans using this User Default, it can be set here; otherwise,
all the times on this page should be zero
Synthesizer setting option: please see the JObserve
Online Documentation for the meaning of the different options
Line Rest Freq: enter the rest frequency of your spectral line
manually; rest frequencies for some commonly-observed transitions are
available via menus under Trans
Band: should be as set on the Source Page
Freq Vel: enter radial velocity (km/s)
Frequency: specify sky frequency. NOTE: even if you will
be using only one or two of the four IFs, enter the sky frequency for
the unused IFs as well, otherwise JObserve will not be able to find a
combination of LO frequencies that will work
Correlator Mode
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