The EVLA Observation Preparation Tool
(OPT) for EVLA Ka band observations with the VLA
correlator
This page is meant to give additional information on the
Observation Preparation Tool (OPT) to allow for temporary
deviations from the information in the OPT manual. It is
mainly intended to provide information for scheduling
proposals accepted for EVLA time in the Ka band with the VLA
correlator (before 2010 February/March) and any other
scheduling with the OPT.
Last modified on
2009 Sep 14
NOTE: This is new, web based software!
Temporary server outages, some fixed delays in logistics or
potential other problems may prevent you from submitting a schedule
at the last moment, so plan to finish well (i.e. days) before your
scheduled observations.
Address for getting help (please use "OPT help" in the
subject line).
The OPT is needed to properly tune the new Ka band
receivers of the EVLA; this cannot be done with the current VLA
scheduling software (i.e., JObserve or observe). The OPT is the only
scheduling software available for EVLA observations. For the moment
you will be using a temporary release of the OPT to allow for the
opportunity to observe at Ka band with the VLA correlator.
Unfortunately, the OPT does not interact with the
Proposal Submission Tool (PST) to obtain information automatically.
This means that you will need to go to the
location of the OPT and enter
this information using the instructions below.
You can also reach the location of the OPT through the general
my NRAO Portal (currently a link to
the OPT is located in the Dashboard General News).
We recommend using FireFox on a Linux machine for best
tested performance. However, Internet Explorer 7, Safari and Chrome
should work as well (but have not been extensively tested).
We strongly recommend to exercise
patience when using the tool (do not click with the mouse while the
interface is busy).
We are continuously updating the manual, perhaps also
with your feedback (please send feedback to
VLAhelp). We
keep the latest version (2009 Mar 08)
here.
For help with the tool other than can be found in the
documentation please send an email to
VLAhelp@nrao.edu
with "OPT help" in the subject line.
Occasionally we will have to update the software, which
makes the web interface unavailable. Please be patient and try again a
bit later, or let us know your constraints or concerns in advance.
Please read the documentation
(OPTMANUAL.pdf)
first. It should get you the general idea of scheduling with the
OPT. However, the final login procedure has not yet been implemented,
and that is why we needed to create this page here. When you are ready to
start the scheduling (Chapter 2) you should first use the steps
outlined here.
Note that we have made some very recent changes that haven't made
it to the manual yet, such as the placing of the scan "Intents"; we
will add these recent changes to the manual as soon as possible.
Point your browser to
e2e.nrao.edu/opt.
Use your PST login and password to enter the tool. Please be
patient when using the tool. As it is a web application, sometimes
connecting to the NRAO data base takes longer than you would want it
to last. In particular, please do not click ahead, but wait for operations
to finish. Also try to avoid using the browser "back" button to
backtrack to a previous page; all pages have a link to get you back
(usually on the top of the page or in the left hand side column).
After you have logged in to the OPT web application, you should be
in the OPT (navigate to the OPT if needed - see the documentation on
how to do that). To create your project use the menu strip at the
top and select: File -> Create New -> New Project.
This should pop up a dialog box with some fields that must be edited.
A note of caution: you want to do this in the account of the person
that is submitting the observing schedule as there is no way currently
to transport the codes you are entering when sharing the XML files.
Make sure that the "Test project" box is not checked.
Enter the "Project Code" from your proposal (your
project/legacy code can be found in the PST or in the email from the
Scheduling Officer: A....., e.g. AS987, without using spaces!)
Enter the "Proposal Code" from your proposal (your proposal
code can be found in the PST or in the email from the Scheduling
Officer: 09A-..., e.g. 09A-191, without the "VLA/" part.)
Click "Add". You will now have a "Project" with these codes
which is known to the data base. Note that if your codes do not appear
in the data base as entered by the PSC (after approval of your proposal),
you won't be able to submit the schedule for observations.
Without doing anything further, use: File -> Save all
to check your code is (still) unique. If not, bad things will
happen so better check it now ;-). If nothing bad happens, you have a
unique code and can continue. You only need to check this (this) once.
(If bad things happen (HTTP error) you or someone else has already
claimed this proposal code; check with your colleagues to resolve.)
Proceed with your scheduling as outlined in the documentation,
with these important notes:
-> Important for line experiments, add that no other
programs can be run in the other subarray in the comments to the
operator. This is needed because at the moment the number of Ka-band
(and S-band) receivers is less than half of the array and the VLA
correlator will be set by the subarray requesting the largest amount
of antennas (typically continuum if the other subarray is used).
-> Note that for dynamically scheduled files you will be given the
option to add weather constraints in a table on the SB details page,
in particular for wind and API limits. The default at the
moment is to leave them not set (i.e., any weather; sunshine, rain,
storm..), which is not a good idea for high-frequency observing. We
recommend Ka-band values of 10 deg for the API and 6 m/s for wind; see
the Dynamic
Scheduling page for recommended values at other bands.
-> Remember that observing at Ka-band has two hardware
restrictions. First, IF pair AC cannot be used to observe frequencies
below the lower edge of 32.24 GHz (in practice thus a center frequency
of 32240 MHz plus half the bandwidth in MHz used); use IF pair BD
instead. Second, the AC and BD IF pairs can only be separated up to
within about 10.5 GHz, where thus only IF pair BD can be tuned below
32.24 GHz. The OPT should issue warnings or errors for these
occasions, but be aware of this just in case it does not. For more
information read section 2.2.4 in the documentation.
-> Observing at any band has also two hardware
restrictions. If the IFs are separated by more than 2 GHz, then IF
pair BD must be the lower of the two. Last, but not least, the
minimum integration time for the VLA correlator is 3.3
seconds. Note that there is no error/warning generated for this!
-> Maybe not so obvious, but "fast-switching" is
now done using "scan loops" (see sections 4.3.3 and 4.3.4 in
the documentation).
Don't be shy to ask for help if you need it (send your query to
VLAhelp).
We are also interested to hear your suggestions and comments or any other
feedback you may have at the same address.
