Entering Proposal Information

Introduction

This section is where you enter the title and abstract. You also must select the category that your proposal falls into. Additionally you are asked for any related proposals, what level of staff support you will require, and whether or not you will be present at the telescope for the observations.

Various length constraints are noted, or warned about, on this page. If these constraints are not met then a popup warning message will inform the user of the problem.

Title

The title of your proposal. For a submitted proposal, the title can be at most 80 characters long.

Abstract

A concise description and justification of the science goals of the proposed program. The abstract must be written in standard ASCII and should be no longer than 200 words and no shorter than 10 words.

Proposal Categories

Proposals are categorized in various ways, primarily to simplify reviewer assignment and the reporting of telescope usage statistics. Select at least one from each of the categories below.

Proposal Type

Beginning on 7 Jan 2011, NRAO recognizes four different types of proposals (see the relevant Section ). These are:

1. Regular Proposal: Regular proposals are for modest total time requests on Observatory facilities. The Call for Proposals specifies the maximum number of hours a Regular proposal is allowed, which may depend on the capabilities of a facility.
2. Large Proposal: Large proposals are for large total time requests on Observatory facilities. The Call for Proposals specifies the maximum number of hours a Large proposal is allowed, which may depend on the capabilities of a facility.
3. Triggered Proposal: Proposals for pre-planned observations of transients whose event times are unknown a priori; well-defined triggering criteria are required. Triggered proposals must be submitted on the semester deadline.
4. Director's Discretionary Time: Proposals for Exploratory Proposals, Targets of Opportunity, or Education and Public Outreach. These may be submitted at any time.

Proposal Sponsor

Beginning 3 Feb 2014, NRAO recognizes proposal sponsors. Sponsored proposals have guaranteed telescope time because of support from external organizations (the sponsor). The default is that a proposal is Not Sponsored''. Users should not change the default unless they have been identified by the external organization as part of the sponsored program.

Scientific Category

This category indicates the types of objects and the science that you wish to do. The selections are:

1. Solar system, stars, planetary systems: Sun, planets, comets, IPM; exoplanets; main sequence stars; active stars; stellar winds; AGB & post-AGB stars; PNe; novae
2. Gravitation waves and energetic transients: supernovae, gravitational wave sources, gamma-ray bursts, tidal disruption events, fast radio bursts (including persistent radio sources), exotic/unknown transients
3. Pulsars and compact objects: millisecond pulsars, cataclysmic variables, black hole and/or neutron star x-ray binaries (including ULX), pulsar timing, pulsar proper motion
4. Star formation: young stellar objects; protostars; jets, outflows; T Tauri stars; circumstellar disks; protoplanetary systems; astrochemistry
5. Interstellar and Intergalactic medium: galactic HI & OH; ISM magnetic field; SNRs; HII regions; astrochemistry
6. Normal galaxies, clusters, and groups: Galaxies (continuum), including galaxies in groups & clusters: disk emission; star formation; magnetic fields; galactic winds; starbursts; intracluster emission & ICM astrophysics
7. Extragalactic structure: Galaxies (line): galaxy structure; galaxy kinematics; chemistry and dynamics; gas in galaxies
8. High-Luminosity AGN: AGN, high-luminosity: FR II radio galaxies, quasars (including radio quiet quasars), blazars, BL Lacs
9. Low-Luminosity AGN: AGN, low-luminosity: FR I radio galaxies, FR 0 radio galaxies, Seyfert galaxies, quiescent SMBH, Sgr A*
10. High redshift and source surveys: High redshift and source surveys: High-z objects; extragalactic source surveys; galaxy formation; gravitational lenses; large-scale structure & clusters (as cosmological probes); CMB; early universe
    

     

Observing Type

The observing types are general descriptors of your proposed observations. They give the NRAO support staff a better idea of how you will be doing your observations. You should select all the observing types that apply for your observations. Not every observing type is relevant for each telescope. Below is a list of observing types:

1. Continuum: continuum emission observations (e..g, synchrotron emission).
2. Spectroscopy: spectral lines observations.
3. Polarimetry: observations to measure the polarization properties of a source or field.
4. Single Pointing(s): observations of a single position or field.
5. Grid Mapping/Mosaicing: observations of a region by taking data at multiple positions or fields. Typically called Grid Mapping for single-dish telescopes and Mosaicing for interferometers.
6. OTF Mapping: observations of a region by scanning the telescope while taking data (aka On The Fly Mapping).
7. Sun: Solar observations which may require special techniques because of the large dynamic range.
8. Monitoring: multi-epoch observations of a target (e.g., time variability).
9. Solar System: observations of Solar System objects that do not move at the sidereal rate.
10. High Time Resolution: observations that require fast sampling in time.
11. Pulsar: observations of pulsars which often requires special detectors.
12. Radar: observations to detect radar signals reflected from a celestial object which often requires special detectors.
13. Geodesy: observations designed to measure and understand the Earth's geometric shape, orientation in space, or gravity field.
14. Astrometry: precise measurements of the position or motion of a celestial object.
15. VLA Subarrays: VLA observations that divide the array into two or more smaller arrays (e.g., observe two different targets simultaneously).
16. Other:

     

Related Proposals

Here you should enter the proposal codes for any previous NRAO proposal that are related to the current proposal. These proposals can be any prior proposals submitted by the same group, whether approved or rejected. They may also include related proposals for another NRAO telescope that were part of a multi-telescope project.

Plan of Dissertation Research

The Plan of Dissertation is important in the proposal review process and should be well written; it is not a placeholder and should not be a replica of the proposal. The plan must be compliant with the follow requirements:

• It must follow the Observatory's Plan of Dissertation Research template. The template is available below in word or latex formats:
• word template,
• latex template.
• The section headers in the template should not be changed but the instructional text within the template should be replaced.
• It must be uploaded as a Portable Document Format (pdf).
• It is a maximum of two (2) pages.
• There is a minimum of one inch margins on all sides and the pages are US letter size.
• The minimum font size is 11 point, which includes the font in figure captions, table captions, table headers, content, and references. Fonts in rescaled figures should be legible.

The plan provides some assurance against a dissertation being impaired by adverse referee comments on one proposal, when the referees do not see the full scope of the project. This requirement applies to all three of the AUI major instruments: VLA, VLBA and GBT.

The Plan of Dissertation Research can be uploaded either from the Author's page or from the student's user profile at: Profile > My Profile > User Preferences. The Plan of Dissertation Research is associated with an Author which can then be used in one or more proposals. The Plan of Dissertation Research field here is only used to display the current status. For example, if there are no students listed on the proposal who are observing for their thesis the text box will display: “Dissertation Research Plan(s) not required'

Joint Proposals

Proposals requesting multiple telescopes are considered joint proposals.   Select one or more telescopes from the list. You must submit a separate proposal for each NRAO telescope; those proposals must each include the same scientific justification. The cover information for each NRAO telescope may differ. The PST must be used if either the GBT, VLA, or VLBA are used in the joint proposal. VLBI proposals which request the GBT or VLA (or the HSA, for example) as elements of the VLBI array do not need separate proposals - those telescopes can be selected as separate VLBI stations from a VLBA/HSA proposal.

Beginning 3 Feb 2014, joint proposals include external facilities (e.g., HST).  Currently, there are eight external facilities: ALMA, JWST, HST, Swift, Chandra, XMM-Newton, NICER, and IXPE.  For ALMA and JWST please specify the number of requested hours.  For HST please indicate the number of orbits. For Swift, Chandra, XMM-Newton, NICER, and IXPE please specify the number of ksec.   Please put any technical information regarding the external facility on the specified textbox on Technical Justification page. 

N.B.,  HST "Snapshot" observations are not supported under the HST-NRAO Joint program since there is no guarantee that Snapshot targets will be completed.

N.B., Chandra ToO proposals are not supported under the Chandra-NRAO joint program.

The Authors section is where you enter the contact information for the principal investigator (PI) and any co-investigators (co-I). A table of authors is shown (initially this will simply be the user for a new proposal, and will be filled in as authors are added to the proposal)

Adding Authors to a Proposal

Click the Add' button to search and add an author to the proposal.

Searching for an Author in the NRAO User Database

First you must search for the author in the NRAO User Database to see if they have registered. (All authors must be fully registered in the NRAO User Database.) To do this just enter their name (first name, last name, or full name) in the search area and press the Search'' button. If you find the right person, select the circular toggle button for that person. Even if the author's information is incorrect please continue to add the author to your proposal. Later you will be able to e-mail this author to ask them to update their user profile.

Edit Author Information

To edit author information click on the author's name. Please make sure the author information is up-to=date, especially if you copied an old proposal. Click on Email'' to email the author to ask them to edit their user profile if it is incorrect. If an author has updated their user profile click on Update'' to update this information in the proposal. Click on Delete'' to delete an author from the proposal.

Plan of Dissertation Research

If an author is observing for a thesis use the Thesis'' checkbox. If the Plan of Dissertation Research had already been uploaded it should appear in the Dissertation Plan column. To upload the Plan of Dissertation click on the author's name and follow the instruction to upload a file (PDF format only).  It is important to keep the Plan of Dissertation Research up-to-date. To replace the old plan with a new plan click on Replace File''. The Plan of Dissertation Research is tied to the student and therefore may be uploaded or replaced from the Profile tab (Profile > My Profile > Users Preferences).

Selecting the Principal Investigator

The principal investigator (PI) is defined to be the lead author on the proposal. Use the Principal Investigator'' menu to select that author from the available authors.

Selecting the Contact Author

The contact author (CA) is the individual on the proposal with whom NRAO staff will correspond when discussing the scheduling of the proposal. Use the Contact Author'' menu to select that author from the available authors.

Rearranging the Order of Authors

You can rearrange the order of the authors by using the up/down links in the first column of the table of authors.

The Sources section is used to enter the positions and velocities/redshifts (where relevant) of your target sources. As of the 1 February 2013 deadline the NRAO now requires proposers to specify their source lists in full. This enables the Observatory to identify potential conflicts between observing programs and to better understand scheduling pressure on the instruments it operates. It may be the case that the final target list has not been selected at the time a proposal is submitted. In such cases, all potential targets and fields should be listed. The only exceptions to this requirement are for Triggered proposals to observe targets that are unknown a priori. Proposal source lists are not made public by the Observatory. For some types of observations, knowing the calibration source is important for evaluating the technical justification, and the calibration source should be included in the source list.  Calibration sources may be included for all types of observation, but their inclusion is not required.

There are three different ways to do this. You can (1) enter the information by hand, one source at a time; (2) search for source information from NED/SIMBAD; or (3) load source information from a local data file.

Merely adding a source in the Sources section does not ensure that time is requested to observe that source. The source must also be paired with a telescope resource, and that source-resource pair must be added to a session (see the Introductory Sources, Resources, and Sessions Section and the Section on Sessions).

Source Groups

Source groups are intended to make it easier to handle observations of a large number of sources within a single observing session. The source/resource pairs which form the basic units of observing sessions (see the Introductory Sources, Resources, and Sessions Section and the Section on Sessions) refer to source groups. Click on the New Source Group'' button to add a new source group. A single source may belong to multiple source groups. We provide examples of how to use groups for the GBT and for the VLA.

Adding Sources by Hand

Once a group is created you can add new sources by hand by clicking on the "Add" button and then enter the appropriate information in the entry fields.

For the VLBA/HSA or GMVA, if multiple fields are to be correlated for some or all pointings, the source positions entered should be the desired pointing centers, and the Scientific Justification should make clear the selection criteria for which sources will be correlated within a given pointing. See §2.3.6 for more details on multiple-field correlation.

The entry fields for adding a new source include:

• Source name: A unique name for the source. This should be less than 60 characters long and contain no spaces.
• Coordinate System: The only coordinate system available at this time is equatorial.
• Epoch: The epoch for the coordinate system used to define source positions. Only J2000 or B1950 are currently allowed. The default is J2000.
• Longitude center: The longitude coordinate (e.g., right ascension) of the source or the reference position for a multi-point map, specified as hh:mm:ss.
• Latitude center: The latitude coordinate (e.g., declination) of the source or the reference position for a multi-point map, specified as dd:mm:ss.
• Longitude range: The longitude coordinate range (±) used for multiple-pointing mapping, specified as hh:mm:ss. Should be 00:00:00 for single-pointing observations.
• Latitude range: The latitude coordinate range (±) used for multiple-pointing mapping, specified as dd:mm:ss. Should be 00:00:00 for single-pointing observations.
• Velocity reference frame: The options for the velocity reference frame will depend on those available for the different telescope control systems. VLA/VLBA: Barycentric, LSRK, or Topocentric; GBT: Heliocentric, Barycentric, LSRK, LSRD, Topocentric, Galactic, or CMB. The default is LSRK.
• Velocity convention: The velocity convention may be: Optical, Radio, Relativistic, or Redshift. The default is Radio.
• Velocity: If the velocity convention is either optical, radio, or relativistic then the this value is the velocity of the source in km/s; while if the velocity convention is redshift then this value is the redshift (z) for the source. The default is 0.0.
• Calibrator: A checkbox indicating whether or not the target will be used for calibration purposes. The default is n.''

Once the source information is entered, click the "Save" link. A message will report either that the source was successfully added, or that some error was found. In the latter case the offending entry or entries will be pointed out; simply correct those entries and press the "Save" link again. The source will now appear in the source table on the Sources section. Note that a source which is a member of multiple groups will appear multiple times in the source table.

Find Source in NED/SIMBAD: Searching For Sources

You can search NED and SIMBAD for source information if you know the object's name. Click on the "Search NED/SIMBAD'' button; then enter the object's name (e.g., B0329+54) in the " Target Name'' field and press the " Search'' button. You will then be presented with the result of the search. The search currently goes through NED and SIMBAD, and names should adhere to their conventions (e.g., GRS 1915+105, NGC 4500, M31, HD19688). Only the most direct match is returned; that is, no extended name search is done. For example, M31 returns M31, not Mayall II, etc.

Load Sources From File: Reading in a Source List from a File

N.B., the format has changed twice: for the 1 February 2010 deadline and for the 1 February 2013 deadline. Click the "Convert'' button to convert the most recent old format to the new format. For the 1 August 2013 deadline we use yY/nN instead of true/false for the calibrator flag but both formats are accepted in the input file.

You can read in some or all of your sources from a local ASCII file that you have edited offline from the PST. Click on the "Import'' button to view the browse/load options. To load the contents of the file into the PST, first enter the path and name of the file into the "Source Data File'' field, either by hand or using the "Browse'' button, and then click the "Load'' button.

This ASCII file must be formatted as follows:

SourceName; Group Names; Coordinate System; Epoch; Longitude; Latitude; Reference Frame; Convention; Velocity; Calibrator;

The delimiter is the semicolon (;) character. A delimiter must be present for every field. Since there are ten fields, each line in the text file must have ten delimiters. There must be a carriage return at the end of each line. If a line starts with the number symbol (#) or a star (*), the line will be ignored--that is, this line will be treated as a comment. N.B., the longitude and latitude coordinates must use sexagesimal units (e.g., hh:mm:ss and dd:mm:ss). Here is a simple example:

NGC3242; PNe; Equatorial; J2000; 10:24:46.1; -18:38:32; Barycentric; Optical; 4.70; n;

White space (e.g., space character, tab character) at the beginning and end of a line is permitted but will be ignored. Likewise white space immediately preceding or following the delimiter is also permitted but will be ignored. White space within a field, as in "a b c'' is preserved. For example, the following two lines will be handled identically by parsers:

NGC3242Pos1 ; PNe ; Equatorial ; J2000 ; 10:24:46.1 ; -18:38:32 ; Barycentric ; Optical ; 4.70; n;

NGC3242_Pos1;PNe;Equatorial;J2000;10:24:46.1;-18:38:32;Barycentric;Optical;4.70;n;

However, there must not be spaces in the field for the source name.

Optional fields are permitted and include Group Names, Coordinate System, Epoch, Reference Frame, Convention, and Velocity. An optional field may be left unspecified. For this purpose unspecified means either that there are no characters present for that field, leading to consecutive delimiters (e.g., ;;''), or that the only characters in that field are white space characters (e.g., ; ;''). The following example shows the minimal amount of information that must be specified:

NGC3242;;;; 10:24:46.1 ; -18:38:32;;;;;

Some fields are allowed to hold multiple values. The comma (,) character will be used to separate the multiple values. The same rules regarding white space apply here as in between fields--i.e., white spaces immediately preceding or following the value delimiter is ignored. The comma after the final value is not mandatory. For example, the following lines all represent the use of multiple values in the second field and will be handled identically by parsers:

NGC3242_Pos1; G1, G2, G3; Equatorial; J2000; 10:24:46.1; -18:38:32; Barycentric; Optical; 4.70; n;

NGC3242_Pos1; G1, G2, G3,; Equatorial; J2000; 10:24:46.1; -18:38:32; Barycentric; Optical; 4.70; n;

NGC3242_Pos1;G1,G2,G3; Equatorial; J2000; 10:24:46.1; -18:38:32; Barycentric; Optical; 4.70; n;

Modifying Source Groups

To modify a source group click on the group name. Rename a source group by editing the text field and clicking the "Save'' button; click the "Delete'' button to delete the group; or click the "Cancel'' button to cancel. To modify sources within a source group a similar procedure is used, except now click on the source name located with a source group table. The different attributes of a source (RA, Dec, etc.) may be edited and then saved. Both sources and source groups may be reordered using the up/down links.

NOTE: When deleting source groups that are included in a session the PST will warn you that by deleting the source group the session will also be deleted. At this point you can either proceed with this operation or cancel.

The Resources section is used to specify the telescope setups to be used for the proposed observations. There is one such section per telescope. Each observing setup is called a resource; each resource is defined by the receiver, back end, spectral mode, configuration, etc. to be employed.

What is a Resource?

A resource consists of an array configuration (for the VLA) or a combination of stations (for the VLBA/HSA and GMVA), a front end receiver, a back end processor, and the technical details of how they are to be used together. A resource is given a name which can be any unique character string. It is used to identify a specific experimental setup, e.g., 'setup1','Cont_43GHz', 'mapping_with_SP', 'Bconf-Xband', 'B14a', 'SiO_30kms'.

When defining an observing session you will combine a source group with one or more resources to specify what and how to observe. A single observing session may employ multiple resources, with some restrictions (e.g., only a single VLA array configuration may be used in a given session).

The Resource Page is different for the four telescopes - VLA, GBT, VLBA/HSA, GMVA - (although the VLBA/HSA and GMVA instruments are very similar). For the GBT there are resource groups that work the same way as source groups. One or more resources are selected within a given resource group that are later associated with a source group within a Session. For the VLA, the VLBA/HSA, and GMVA there are no resource groups but a list of resources that can be combined later within a given Session.

GBT Resources section

The GBT Resource section is where you select the back ends that you wish to use during the proposed observations. You are also asked to provide information such as rest frequencies, desired bandwidths, desired spectral resolution, desired time resolution, etc. Click on New Resource Group'' to add a resource group. Once a resource group exists click on the Add'' button to add a resource.

You are then asked to fill in the following information:

• Resource Name: A unique name for the resource.
• Receiver: The GBT receiver that you wish to use for this resource. A pull-down list of the receivers is available.
• Back End: The back end/observing mode combination that you wish to use for your observing. Depending on which back end was selected you may have to provide more details for the resource. For additional details consult the GBT Proposer's Guide: GBT Proposer's Guide. This information includes:
• Digital Continuum Receiver (DCR)
  • Rest Frequencies: A comma separated list of rest frequencies.
  • Instantaneous bandwidth: The desired bandwidth.
  • Desired time Resolution: The minimum dump time requested.
• JPL Radar Back End
  • Rest Frequencies: A comma separated list of rest frequencies.
  • Desired Frequency Resolution: The frequency resolution needed to perform the requested science.
  • Time Resolution: The minimum dump time requested.
• VErsatile GBT Astronomical Spectrometer (VEGAS): VEGAS consist of 8 independent spectrometers. First select the observing type, the number of beams, and the number of spectrometers before specifying the details for each spectrometer. For observing type Continuum only mode 1 is currently available. For observing type Spectral Line'' modes 1-29 are available where up to 8 spectrometers can be used. For each spectrometer the following information is specified:
  
  • Mode: The desired mode. See the proposer's guide for details about each mode.
  • Bandwidth: The desired bandwidth which depends on the mode and cannot be edited.
  • Rest Frequencies: A comma separated list of rest frequencies. The number of rest frequencies must equal the number of spectral windows.
  • Spectral Resolution: The spectral resolution which depends on the mode and cannot be edited.
  • Integration Time: The integration time. The value must be between a specified range (listed in the proposer's guide). Currently the integration time must be the same for all spectrometers.
  • Date Rate per Spectrometer: Based on the mode and integration time, the data rate is calculated and displayed.
• Caltech Continuum Back End (CCB): The CCB is a sensitive, wide-band detector with 14 GHz of instantaneous bandwidth that cover 26-40 GHz. The CCB may only be used with the Ka-band receiver.
• Mustang 2: A 223-feedhorn bolometer camera that is both a frontend and backend operating at W-band.  You must have permission from the instrument team to use this camera.
• Breakthrough Listen: A non-standard backend developed for the Breakthrough Listen project.  You must have permission from the observatory director to use this backend.
• Vegas Pulsar
  
  • Bandwidth: the desired bandwidth from the menu.
    
  • Observing Mode: the pulsar observing mode (timing or search).
    
  • Polarizations: the polarizations (full stokes or total intensity).
    
  • Channels: the number of spectral channels.
    
  • Dedispersion: coherent or incoherent dedispersion.
    
• Other

• Rest Frequencies: A comma separated list of rest frequencies.
• Name of the special back end: Short descriptive name.
• Comments: Any comments about this back end.

The GBT Resource section is where you select the back ends that you wish to use during the proposed observations. You are also asked to provide information such as rest frequencies, desired bandwidths, desired spectral resolution, desired time resolution, etc. Click on New Resource Group'' to add a resource group. Once a resource group exists click on the Add'' button to add a resource.

Additional GBT Information

Please consult the GBT Proposer's Guide for more information.

VLA Resources section

The VLA Resources section allows you to create, edit, and remove resources appropriate to the VLA, specifying such information as the array configuration, observing frequency, frequency resolution, and number of channels. You must create a separate resource for every different combination of these attributes. Click on the Add'' button to add a resource. Details about how to make these choices may be found in the VLA Observational Status Summary:  VLA Observational Status Summary An VLA resource is defined by the following information:

• Resource Name: A unique name for the resource.
• Configuration: The array configuration.  As "Any" configuration is not specifically tied to a time period, when selected you must also input the number of semesters that are required to carry out the observations. More specific "Any" configuration details (e.g., about "Move" time) can be entered in the Session.
• Receiver: The VLA receiver that you wish to use. This specifies the range of frequencies within which you will be observing. The pull-down menu shows the available receivers.
• Back End: The back end you wish to use. Currently there are 5 "backends" which are essentially different elements of the WIDAR correlator that are available. General and Shared Risk Observing - Wideband are those modes within the correlator that are set up for wideband observing; General and Shared Risk Observing - Spectral line are those modes within the correlator that are set up for Spectroscopic (or mixed Spectroscopic and Wideband) observing; General Observing - Pulsar binning is used to separately image different phase ranges of a pulsar signal (of known period); General Observing - Phased-array pulsar records the summed signal of the phased array instead of a signal for each baseline separately; and finally there is RSRO -- Resident Shared Risk Observing and VLA Commissioning Staff Observing programs which provides access to the extended capabilities of the VLA. For descriptions of these different observing capabilities, see the Call for Proposals. The choice of back end brings up further information and tools to assist in selecting the proper choices to set up the correlator:
• General and Shared Risk Observing - Wideband: The Wideband part of General and Shared Risk Observing is now incorporated into the PST itself (spectroscopic or mixed wideband/spectroscopic modes still use an independent tool - see below). One may select 8-bit or 3-bit sampling for the basebands, the frequencies of the baseband centers, number of polarization products, and the dump time. Some combinations are General Observing, some are Shared Risk, and some are Resident Shared Risk (RSRO). The PST will report these different Shared Risk and Resident Shared Risk when trying to save a Resource. One cannot save a RSRO configuration under this Backend.
• General and Shared Risk Observing - Spectral Line:
  
  • RCT-proposing.  A special stand-alone version of the Resource Catalog Tool (RCT) which differs slightly from the observer's RCT found in the Observing Preparation Tool (OPT) Suite.   RCT-proposing should be used by proposers requesting spectral-line resources or non-default VLA WIDAR resources.  For guidelines about the RCT-proposing please see the Proposer Generated Resource page.  Once a given resource is made, please download the PDF that captures its parameters using the tool's interface (under the Validation tab). The generated PDF file should then be uploaded to the PST.  Please use the same resource name in the RCT-proposing PDF and the PST.
    
  • Receiver Finally, RCT-propsing and the PST are independent tools, so the correct Receiver should still be selected by the proposer in the PST resource.
• General Observing - Pulsar binning is used to obtain wide-band imaging data on a pulsar of known period, separated into different pulse phase bins.  This can be used, for example, to image times when the pulsar is "on" separately from those when it is "off".  While several of the options are shared with the Wideband backend (see above), some are specific to this mode.  In particular, there is a tradeoff between bin width (period divided by number of bins) and the total number of subbands processed by the correlator.  The PST will check your selections, and not allow invalid setups.  The total data rate will be reported, and can not exceed 60 MB/s.  See the Observational Status Summary for more details.
• General Observing - Phased-array pulsar (YUPPI): In this mode the individual antenna signals (voltages) are summed coherently, producing high-time-resolution data for a single synthesized beam within the overall field of view.  The summed data is recorded in one of two modes:  "Search Mode" simply produces high-time-resolution spectra (power versus time, frequency, and polarization); "Fold Mode" uses a user-supplied pulse period ephemeris to average many pulse periods together, producing averaged pulse profiles as a function of time, frequency, and polarization.  In both cases you will be required to enter bandwidth, and desired time and frequency resolution.  Fold mode also requires desired pulse phase resolution (number of bins).  The PST will check that your selections are possible, and will report the total data rate.  More details about the constraints and tradeoffs between parameters are available in the Pulsar section of the Observational Status Summary.
• VLA+LWA: In this mode the individual antenna signals (voltages) are written to VLBI Data Interchange Format (VDIF) files. These will be jointly correlated offline with New Mexico stations of the Long Wavelength Array (LWA) through the LWA software correlator. For shared risk observing this mode is available for a center frequency of 76 MHz, a bandwidth of 8 MHz, and 4-bit VDIF output.
• VLA+LWA RSRO: This mode is similar to the standard VLA+LWA and should be used for requests that require a setup that differs from that offered through shared-risk or general observing. For more details check VLA offered capabilities.
• WIDAR RSRO This is the "backend" one should select for the highly successful Resident Shared Risk Observing program and NRAO commissioning staff to help NRAO accelerate commissioning of the VLA's full scientific capabilities. RSRO participants obtain early access to the VLA's growing capabilities, in exchange for a period of residence in Socorro to assist with commissioning. Information about the RSRO program can be obtained at VLA RSRO program.

VLBA/HSA Resources section

The VLBA/HSA Resources section allows you to create, edit, and remove resources appropriate to the VLBA and HSA, specifying such information as the stations (antennas) requested, observing frequency, number of baseband channels, polarization, sample rate, and other observing-time setup information. In addition, this section allows you to select a processor (correlator) and correlator set-up information, such as the requested polarization products, number of spectral channels, number of correlation passes, and the averaging time.

You must create a separate resource for every different combination of these attributes. Click on the Add'' button to add a resource. Details about how to make these choices may be found in the VLBA Observational Status Summary.  A VLBA/HSA resource is defined by the following information:

• Resource Name: A unique name for the resource.
• Stations: The requested stations. Checking VLBA'' selects all VLBA stations. Checking HSA'' selects all of Ar, Ef, GBT, and Y27 (the phased VLA). In both cases individual stations may be unchecked, once selected. VLA-Y1 selects a single antenna of the VLA to be in the VLBI array. Y1 and Y27 may not both be selected. Currently, the use of VLA-Y1 as a VLBI station is Shared Risk Observing (see the Shared Risk section of the VLBA Proposal Guide). Codes for geodetic stations may be entered in the box marked Geodetic''. For the HSA, the stations that may be selected depends upon the Observing System selected, as some stations may not have the needed hardware or software installed. The discussion of which stations may be selected depending upon Observing System will be discussed under Observing System''. Beginning with the 2013B semester (1 February 2013 deadline) the GBT will no longer provide setup and overhead time prior to the beginning of the VLBI observations. All VLBI proposals requesting the GBT should include any needed setup and overhead time in the time request of their proposals.
• Wavelength: The wavelength at which you wish to observe. The pull-down menu shows the available VLBA receivers. There is no checking whether other antennas (besides the VLBA) are actually equipped with a selected receiver. The Tool will happily allow you to select an array including Ar at 1.3 cm, even though Ar does not have such a receiver.
• Processor: The processor (or correlator) you wish to have the data sent to and correlated. Possible selections are Socorro (the VLBA software correlator DiFX), Bonn (in Effelsberg), JIVE, and Washington (USNO). For most VLBA/HSA experiments, the correlator will be Socorro.
• Observing Mode: New from the 1 August 2014 proposal deadline the Observing Mode'' drop-down menu, has two new entries: Standard/Shared Risk'' and VLBA RSRO''. Some modes, especially for the HSA, are considered Shared Risk. The proposer is notified of Shared Risk status in VLBA Resources as pop-up comments. The VLBA RSRO (Resident Shared Risk Observing) mode is modeled after the successful VLA program of the same name. Details of this program can be found at VLBA RSRO program Selection of VLBA RSRO under Observing Mode'' brings up a RSRO Comments'' text box to describe the resources required. Selecting this mode also allows two extra pages in the Scientific Justification. For both Observing Mode Standard/Shared Risk'' and VLBA RSRO'' the following items can be managed:
• Observing Parameters: Under Observing Parameters'' the following parameters which are specific to observing are listed. The parameters that you wish to set at observe time; these include the Observing System, the Bandwidth per baseband channel. the number of Baseband Channels, and the Polarization. The Aggregate Bit Rate is calculated, based on the other selections.
• Observing System: The Observing System'' allows two different sets of firmware in the RDBE hardware at the VLBA/HSA stations to be selected. Currently, both systems are not necessarily available or ready at all HSA stations. The Observing Systems'' that are now supported are: 1) the Polyphase Filter Bank (PFB) personality of the RDBE FPGA, and 2) the Digital Down Converter (DDC) personality of the FPGA. If the PFB System'' is selected, Bandwidth'' and Baseband Channels'' are filled in by the Tool, and cannot be modified. Further details of these systems can be found at the Call for Proposals (CfP) under VLBA Observing Capabilities'' and the VLBA Observational Status Summary (OSS). The CfP can be found at: Call for Proposals and the OSS can be found at VLBA Observational Status Summary.
  Bandwidth: A pull-down menu lets you select the recorded bandwidth per subband (or baseband channel), in factor of 2 steps from 1 MHz to 128 MHz. If spectral selection'' is to be used (Socorro correlator, or other DiFX installations by special arrangement), the bandwidths specified here are for the recorded bands only -- specifications for the zoom'' band should be communicated directly to the correlator.
  Baseband Channels: A pull-down menu lets you select the number of BBCs, in factor of 2 steps from 1 to 8.
  Polarization: One can observe with right circular polarization, left circular polarization, or both (dual) using the VLBA. In the hardware, each BBC selects either RCP or LCP.
  Aggregate Bit Rate: This is calculated by the tool, by the product of number of Baseband Channels, Sample Rate, and Bits / Sample. Sample Rate and Bits/Sample are no longer selectable by the proposer. They are assumed to be Nyquist sampling and 2 bits/sample.
• Correlation Parameters: The parameters that you wish to set at correlation time; number of Correlator Passes, Integration Period, number of Spectral Points per BBC, and No. of Phase Centers per Pointing. Correlator resources are as valuable as Observing resources, so proposers are asked to justify the correlator resources as well as the observing resources. There are some interactions among correlation parameters as well as among correlator and observing parameters. Most of these interactions are not currently checked in the Tool.
• Number of Correlator Passes: The number of correlator passes required (default one). Note that 2 passes are no longer required for 512 Mbps data at the Socorro correlator. More than one pass may be necessary for correlating at two different positions, or to allow different correlator setups for the same time range of date. Note that multiple positions can be correlated in a single pass with the Socorro correlator (and may be possible at other DiFX installations), and this is recommended if more than 2 positions are required (see the number of fields'' section below). If the multiple field/single pass correlation is used, the number of correlator passes'' field should remain at 1 unless multiple passes are also required for different correlator setups. If more than one correlator pass is required, a brief justification should be written in the Technical Justification Section.
• Integration Period: The averaging time, in seconds, in the correlator (default 2 seconds). The shorter the averaging time, the larger the (rate) field of view. One must balance the output rate of the correlator with the required field of view. While there is no hard upper limit on output data rates, rates above 10 MB/s require specific justification in the Science Justification.
• Spectral Points / BBC: For continuum observations, the default number of spectral points is to have each point represent 0.5 MHz of bandwidth (for example a 32 MHz BBC bandwidth has a default number of spectral points of 64). For spectroscopy, the number of spectral points is 16. For spectroscopy, the number of spectral points depends upon the required velocity resolution. As with averaging time, there is no hard upper limit to the number of spectral points per subband, but requests for more than 4096 points per subband, or values that would lead to a data rate ≥10 MB/s, require specific justification. The output data rate is calculated in the PST and a warning pop-up is given when it is greater than 10 MB/s.
• Number of Phase Centers per Pointing: The maximum number of phase centers to be correlated simultaneously in a single correlator pass (only available with the Socorro correlator, or other DiFX installations by special arrangement). The default is 1. If this feature is used, the source positions entered using this tool for pointings with multiple fields should be the pointing centers (i.e. it is not necessary to list every target source). However, the Scientific Justification should make it clear what the selection criteria for sources to be correlated will be. Use of this feature consumes additional correlator resources (although the increase is nearly constant at 2.5-3x normal'' correlation, regardless of the number of sources generated) and thus usage of this feature should be justified in the Scientific Justification. Due to this increase in required resources, for 2 phase centers it is more efficient to request two correlator passes (in which case number of fields should be set to 1). Thus, this feature should only be used for 3 or more target sources within a single primary beam. In principle there is no upper limit to the number of phase centers, but values which would cause the output data rate to exceed 10 MB/s must be specifically justified.
• Special Features: These are special features in the correlator that may be needed, including Full Polarization, Pulsar Gate, and Output Format Conversion to Mark4, and Baseband Data Copy.
• Full Polarization: If checked, the correlation of all polarization cross-products are requested, for each baseline: RR, RL, LR, and LL. If unchecked, only the correlation of parallel-hand products are requested: RR, LL, or RR and LL, depending on what was observed. Obviously, Full Polarization cannot be requested if only one polarization is observed; the Tool does check this.
• Pulsar Gate: The correlator can gate based on a pulsar ephemeris; i.e., do the correlation only at times when the pulse is on (or off for that matter). If this item is checked, further input to the correlator will be required -- see the Pulsar Gate Observer's Guide:  VLBA Pulsar Gate Observers' Guide
• Output Format Conversion to Mark4: Conversion of DiFX correlator output to the Haystack Mark 4 format is available, and can be selected via the checkbox here.
• Baseband Data Copy: The raw baseband data from each station can be copied directly to user-supplied media.  This could be useful if the data need special correlation which can be provided by another correlator.  As might be expected, there are several restrictions on this special feature (e.g. the number of projects that could use this must be limited).  Baseband data copy is a Shared Risk feature; see the Shared Risk Observing section of the VLBA Proposal Guide.

GMVA Resources section

The GMVA Resources section allows you to create, edit, and remove resources appropriate to the GMVA, specifying such information as the stations (antennas) requested, observing frequency, etc. Currently, the only possible observing setup is that of the RDBE PFB (polyphase filter bank) personality; tests have been made using European and VLBA stations to realize that this is a viable observing mode. Thus the number of baseband channels, polarization, sample rate, and other observing-time setup information is essentially fixed. In addition, this section allows correlator set-up information, such as the requested polarization products, number of spectral channels, number of correlation passes, and the averaging time. The DiFX correlator at Bonn is the only selectable processor (correlator) for GMVA observations.

You must create a separate resource for every different combination of these attributes. Click on the Add'' button to add a resource. Details about how to make these choices may be found at the GMVA Home Page.

A GMVA resource is defined by the following information:

• Resource Name: A unique name for the resource.
• Stations: The requested stations. Checking US'' selects all VLBA stations with a 3mm receiver and the GBT. Checking European'' selects all of the standard European stations for the GMVA. In both cases individual stations may be unchecked, once selected. In addition there is an Other'' box, which may be used to add stations which are not a part of the standard GMVA'', for example the GBT. Beginning with the 2013B semester (1 February 2013 deadline) the GBT will no longer provide setup and overhead time prior to the beginning of the VLBI observations. All VLBI proposals requesting the GBT should include any needed setup and overhead time in the time request of their proposals.
• Wavelength: The wavelength at which you wish to observe. The pull-down menu allows both 3 and 7mm, as pointing (especially at the VLBA stations) may be done at 7mm.
• Processor: The processor (or correlator) you wish to have the data sent to and correlated. The only possible selection for the GMVA is the Bonn (DiFX) processor. Observing parameters are listed for the RDBE PFB: 16 baseband channels, 32 MHz bandwith, dual polarization. The only one of these that can be changed is the polarization. With dual polarization the aggregate bit rate is 2048 Mbps. Correlation parameters can be selected:
• Correlation Parameters: The parameters that you wish to set at correlation time; number of Correlator Passes, Integration Period, number of Spectral Points per BBC, and No. of Phase Centers per Pointing. Correlator resources are as valuable as Observing resources, so proposers are asked to justify the correlator resources as well as the observing resources. There are some interactions among correlation parameters as well as among correlator and observing parameters. Most of these interactions are not currently checked in the Tool.
• • Number of Correlator Passes: The number of correlator passes required (default one). Note that multiple positions can be correlated in a single pass with the Socorro correlator (and may be possible at other DiFX installations), and this is recommended if more than 2 positions are required (see the number of fields'' section below). If the multiple field/single pass correlation is used, the number of correlator passes'' field should remain at 1 unless multiple passes are also required for different correlator setups. If more than one correlator pass is required, a brief justification should be written in the Technical Justification Section.
  • Integration Period: The averaging time, in seconds, for the GMVA, in the Bonn correlator, defaults to 1 second. The shorter the averaging time, the larger the (rate) field of view. One must balance the output rate of the correlator with the required field of view.
  • Spectral Points / BBC: For continuum observations, the default number of spectral points is to have each point represent 0.5 MHz of bandwidth (for example a 32 MHz BBC bandwidth has a default number of spectral points of 64). For spectroscopy, the number of spectral points depends upon the required velocity resolution. As with averaging time, there is no hard upper limit to the number of spectral points per subband, but requests for more than 4096 points per subband, or values that would lead to a data rate ≥ 10 MB/s, require specific justification.
  • Number of Phase Centers per Pointing: The maximum number of phase centers to be correlated simultaneously in a single correlator pass (only available with the Socorro correlator, or other DiFX installations by special arrangement). The default is 1. If this feature is used, the source positions entered using this tool for pointings with multiple fields should be the pointing centers (i.e. it is not necessary to list every target source). However, the Scientific Justification should make it clear what the selection criteria for sources to be correlated will be. Use of this feature consumes additional correlator resources (although the increase is nearly constant at 2.5-3x normal'' correlation, regardless of the number of sources generated) and thus usage of this feature should be justified in the Scientific Justification. Due to this increase in required resources, for 2 phase centers it is more efficient to request two correlator passes (in which case number of fields should be set to 1). Thus, this feature should only be used for 3 or more target sources within a single primary beam. In principle there is no upper limit to the number of phase centers, but values which would cause the output data rate to exceed 10 MB/s must be specifically justified.
• Special Features: These are special features in the correlator that may be needed. For the GMVA, Full Polarization is the only one selectable.
• Full Polarization: If checked, the correlation of all polarization cross-products are requested, for each baseline: RR, RL, LR, and LL. If unchecked, only the correlation of parallel-hand products are requested: RR, LL, or RR and LL, depending on what was observed. Obviously, Full Polarization cannot be requested if only one polarization is observed; the Tool does check this.

The Sessions section is used to construct observing sessions. As defined earlier, a session is generally a contiguous block of observing time on the telescope. Many proposals involve one observing session in a day. Proposals may request multiple sessions, either as repeats of a single session, or as truly independent sessions.  We provide examples of how one might use sessions to handle various GBT or VLA observations.

On the GBT, a session can contain only one source group/resource group pair.

On the VLA, a session can contain one or more source group/resource pairs. All the source group/resource pairs in a VLA session must use the same array configuration. For example, you must assemble two separate observing sessions if your proposal requests VLA observations in both the A and the B configurations, even if those observing sessions use otherwise identical source group/resource pairs.

Sessions on the VLBA/HSA and GMVA are similar to those of the VLA.

A session has additional attributes, including a session name, a minimum start LST, a maximum end LST, a minimum elevation, a total session time, the number of session to execute plus a separation interval, text describing scheduling constraints, and text for comments. For the GBT, the total observing time for the session is manually entered. For the VLA, each source group/resource pair has an associated observing time, and the total time for the session is calculated as the sum of the observing times requested for the constituent source group/resource pairs. The VLBA/HSA and GMVA use a minimum start GST and a maximum end GST (Greenwich Sidereal Time) since the antennas/stations can be spread over a large geographical range. The total time for a VLBA/HSA or GMVA session, as for the VLA, is calculated given the source group/resource pair's associated observing time.

When constructing sessions in the PST, proposers should be cognizant of their use by the Time Allocation Committee (TAC). Specifically, taking into account the time available as a function of LST, the TAC will assign a scheduling priority to each session in each proposal. The assigned scheduling priority will depend on the linear-rank score of the proposal, the LSTs involved in the session (daytime is harder to accommodate than nighttime), the total time requested in the session, and the competition from better-ranked proposals requesting time at similar LSTs. Further details on how VLA session priorities are established can be found  here.

The default minimum start LST and maximum end LST values are '00:00:00' and '24:00:00.', respectively. If this is not accurate then please enter in appropriate values or use the "Calculate All LST values" button to calculate the LST range based on the source positions included in your Source Group(s). The "Calculate All LST values" button will replace all the LST ranges for all sessions in a proposal. N.B., you have to save at least one session first before the "Calculate All LST values" is available for GBT and VLA proposals.

For the VLBA and GMVA, the GST range must be manually updated. To obtain an accurate GST range that depends on the coordinates of your source(s) and the assumed antennas in the array, we recommend using SCHED's observation planning/plotting capabilities or the EVN online observation planner (PlanObs). 

How to Add a Session?

To add a new session, click on the New Session'' button, then enter the appropriate information in the entry fields.

The fields include:

• Session: The session name uniquely identifies the session.
• Number of Sessions: The number of times this session will be executed.
• Separation: The separation time in days desired between different executions of this session. If you don't care, leave this as zero. This field is often used for monitoring projects. Unusual monitoring requests and comments as to the strictness of the observing interval should be described as scheduling constraints (see below).
• Minimum Start LST (HH:MM:SS): The minimum start LST for the session. (For the VLBA/HSA or GMVA, this field is minimum start GST.)
• Maximum End LST (HH:MM:SS): The maximum end LST for the session. (Again, for the VLBA/HSA or GMVA, this field is maximum end GST.)
• Minimum Elevation (degrees): The minimum elevation for the session. For the VLBA/HSA or GMVA, this field does not exist.
• Available Sources: A menu of available source groups.
• Available Resources: For the GBT, a menu of available resource groups. For the VLA, VLBA/HSA, and GMVA, a menu of available resources.
• Time (including calibration and slew overheads): For the GBT this is the total session time in hours. For the VLA, the VLBA/HSA, and GMVA, this is the time for the specified source group/resource pair in hours. The total session time is the sum of the observing times for the constituent source group/resource pairs.
• Scheduling Constraints: Specify any additional scheduling constraints in this ASCII field. For example:
• Please do not schedule this session through sunrise.
• I am using repeats to accumulate more time for all the sources in the session.
• Observations should be simultaneous with Spitzer. We expect to know the rough Spitzer schedule a month in advance; exact times will not be available until perhaps a week in advance.
• Nighttime observations are required for these HI observations near solar maximum.
• Nighttime observations are required for reduction of RFI.
• Nighttime observations are required for high frequency GBT observations.
• I would like logarithmic sampling of the light curve, with observations 1, 3, 10, 30, and 100 days after the beginning of the outburst.
• Observations every week or two would be ideal but the exact sampling interval is not very important. But observations within a few days of one another are not useful.
• Comments: Enter any comments relevant to the entire session in this ASCII field. For example:
• Given the declination of this source, observing during the antenna move from D to C ("Move") configuration would be an acceptable alternative to the D configuration.
• We will observe only one source in this group: whichever first matches our triggering criterion.
• The time requested for each observing session will be divided amongst the requested frequency bands depending on current source strengths.
• We will not be able to observe with the GBT on November 5, December 24 and April 1.
• Exposure Calculators and Other Helpers Several tools are available for helping you calculate the time on-source needed to achieve a given rms noise level, and to make various decisions regarding GBT mapping and back end setups. Recall that to run the PST, you need to enable Javascript and Cookies in your web browser. If, in addition, you wish to use any of the tools noted below, then your web browser also needs to have a plug-in for Java -- otherwise those tools will fail without any warning. Each tool will start up in a separate window or tab. When you are finished with that tool, simply close its window or tab.
• Calculate Min/Max LST: A button that calculates the minimum LST and maximum LST based on all of the sources within your Source Group(s).  The default min/max LST range is 0-24 hr.  You may enter min/max LST values manually or use the "Calculate Min/Max LST" button.  Before you click this button you must first save the session to identify the Source Group(s).  If you edit the sources, Source Group(s), or minimum elevation you have to recalculate the min/max LST values.  For the VLBA and GMVA there is a "Calculate Min/Max GST" button.
• EVN Exposure Calculator: The link given goes directly to the EVN Calculator. One must select stations, observing band and data rate, time on-source, number of spectral channels, integration time, maximum baseline length, number of polarizations, subbands per polarization (BBC in VLBA parlance) and the bandwidth of a subband.
• VLA Exposure Calculator: To start the VLA Exposure Calculator, click on EVLA Exposure Calculator.'' The calculator will compute either the time needed on source, given a bandwidth and required rms noise, the bandwidth needed, given the time entered and the rms noise, or the rms noise, given the time on source and the bandwidth. One may also select observing season and a range of elevations, which is important for high frequencies -- the system noise is increased for lower elevations and for summer over, for example, autumn, winter, or spring. This is due to changing atmospheric opacity for the season. One may also select the frequency, the number of antennas, single or dual polarization, and the weighting (natural or robust) for making an image.
• GBT Sensitivity Calculator: To start the GBT Sensitivity Calculator, click on GBT Sensitivity Calculator.'' Given various observing parameters (time on- and off-source, observing frequency, back end, etc.), the tool calculates the expected rms noise, brightness temperature, and confusion limit, as well as reporting the assumed gain, aperture efficiency, and channel width.
• GBT Mapping Planner: To start the GBT Mapping Planner, click on Mapping Planner.'' The Mapping Planner calculates the time needed to map an area, including overhead, based on the integration time per beam area (e.g., the results from the Sensitivity Calculator) and the area to be mapped.

Modifying Sessions

Once a session is created click on the session name for an expanded view of the session parameters. Click the "Edit'' button to edit the text fields (e.g., session name, minimum start LST, etc.). Click "Save'' to save, "Delete'' to remove this session, or "Cancel" to cancel the edit operation. To change the sources or resources connected to this session click on either the source or resource listed and use the pull-down menus.

Guidelines for Creating VLA Sessions

Currently, scheduling priorities for the VLA are based on the use of "sessions" in the PST, which are the units of observing time considered by the Time Allocation Committee. The assigned observing priority can strongly depend, in a not very intuitive manner, on specifically how the proposer structures these sessions.  The following is a set of guidelines to help you understand how the definition of your sessions will potentially impact the priority of those sessions.  Note that these guidelines are not directly related to the Scheduling Blocks that you prepare separately (in the OPT) once time is awarded. You should continue writing Scheduling Blocks in the OPT as you have done previously.

The demand for observing times is a function of LST. Some LSTs are in high demand and therefore require a high score in order to receive a high scheduling priority. Since a given session spans a range of LST,  the priority it receives is determined by that part of the LST range with the highest observing pressure.

Here are some guidelines for setting up your sessions in the PST:

• When you have a small number of sources, put each target source into a separate Session.  When you have a large number of sources, put groups of sources in the same part of the sky into separate Sessions. If you have many sources spread over 24h, break them into smaller chunks, e.g., 4-6hr long, by LST range. This way, some of your sessions will fall into low observing time pressure LSTs.
• If you are proposing for more than one band, keep the bands together in one session if the science requires that you do all the bands.  However, if each band is of value separately, then put them in separate sessions.  You may then get awarded different priorities for different bands, with one of the priorities being the best it can be.
• Start by carefully considering the minimum elevation you might use for this observation, and entering it into the field in the PST. Once the session is saved, then use the "Calculate All LST values" button for the automatic calculation of the widest reasonable LST range, given this required minimum elevation.
• It is sometimes helpful to narrow the LST range in order to avoid times with high demand, but remember that narrowing the range, without changing the time requested, will result in a higher time request at each hour of the reduced range.   For example, consider a 4hr project that can be scheduled over a 12hr LST range.  It would be helpful to narrow the LST range if it overlaps with a high LST pressure.  As a rough rule of thumb, if the time requested is two or three times the width of the LST range, it may be beneficial to narrow the range to avoid the busiest LST ranges as shown on the "pressure plots" in the call for proposals, or for other time ranges you anticipate will be in high demand. It is not worth narrowing the LST range to values that lead to requests being more than five times the LST range or to values less than two hours.

VLA Subarrays

The VLA can be split in groups of antennas observing different sources and/or with different resources simultaneously, these are called sub-arrays.  There are some restrictions the number of sub-arrays, the number of antennas in the sub-arrays and how the sub-arrays may observe. See the Sub-array sections of the Observational Status Summary and the VLA Observing Guide for details.

It is not straightforward to set up the PST for sub-arrays because the sessions cannot request a partial array. Since each sub-array will be a session, if the sessions have the total time for the sub-array then total time requested in the proposal will be total time multiplied by the number of sub-arrays. The suggested work around is to divide the total observing time by the number of sub-arrays and use that as the time requested for each sub-array session. For details please see the sub-array section of the Guide to Proposing for the VLA.