General Proposal Info

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Information on requirements for submitting GBT proposals along with the review and scheduling process are summarized under the following topics.

Proposal Deadlines

The GBT proposal deadlines are the same as the NRAO VLA and VLBA deadlines,  namely February 1,  June 1, and October 1of each year.  Each proposal deadline accepts proposals for scheduling in the next trimester.  The year is broken into trimesters beginning with January 1 of the year.  For example, the first trimester of 2002 is formally the period from February 1 through May 31 (see Trimester and Proposal Code Nomenclature below for nomenclature) and normally proposals accepted from the Oct 1, 2001 deadline would be scheduled during  this four month period.  Any proposals that have been approved and  cannot be scheduled in the next trimester will be held and scheduled at the next available opportunity.  Any proposal rejected from a particular deadline must be re-submitted at the next deadline to be considered for a future trimester.
 

Trimester and Proposal Code Nomenclature

Proposal documentation, statistical information and proposal codes all reference specific trimesters by a code of the following form nnX where nn is the last two digits of the year and X is one of A, B or C.  A, B and C refer to the first, second and third trimester of the year respectively.   In particular A denotes Feb 1 through May 31, B denotes Jun 1 through Sep 30 and C denotes Oct 1 through Jan 31. 

GBT Proposal codes take on the format, GBTnnX-NNN, where nnX is the trimester code and NNN is a sequentially assigned number for the particular proposal deadline.
 

Proposal Submission Policies

A detailed description of the proposal submission process is included under GBT Proposals.   A brief summary of the salient points follows.
  • All proposals must be submitted using the GBT Proposal Submission Tool
  • Scientific justification should not exceed approximately 1000 words.
  • Proposal requesting use of the GBT for VLBI (including VLBA) experiments must NOT be submitted using the GBT Submission tool but must be submitted through the normal VLBA/VLBI submission  process.
  • Deadline for acceptance of the proposal will normally be 8am on the day following the deadline.  However this may vary with the specific deadline which will be published about one month before the deadline.
     

Proposal Evaluation Process

A very brief outline of the steps followed at the close of each proposal deadline is described in chronological order.
  1. Immediately upon the close of the deadline (a) basic proposal information is transferred to a database, (b) hardcopies are made of all proposals received and (c) a very cursory check is made for any obvious omissions or gross errors.
     
  2. All proposals are assigned to referees based on scientific expertise of the referees and the details of each proposal. All referees are external reviewers, i.e. outside NRAO.  Every attempt is made to assign five referees to each proposal. Copies of the appropriate proposals are sent by FedEx overnight to each of the referees. (1) and (2) take about 1-2 weeks.
     
  3. Proposals may also be distributed to GBT scientific staff for a technical evaluation.  This evaluation checks that the equipment and observing mode requests are feasible and optimal, and that integration times are accurate.
     
  4. Within 1 to 2 days of sending the proposal copies to the referees, instructions along with a template to be used for their reviews are emailed to each of the referees. The referees are asked to supply a review for each proposal that includes:
    5.  
    • A rating based on scientific merit. The suggested scale is 0 (reject) to 5 where qualitatively 1=poor, 2=average, 3=good, 4=excellent and 5=outstanding.
    • A recommended percentage of requested time.
    • Overall comments on strengths, weaknesses, omissions, or errors, etc., on arriving at the rating.

    The referees are given a deadline to return their reviews The time between sending out the email template and the receipt of all the reviews is usually about 1 to 1.5 months.
     
  5.  Once all referee reviews have been received, a brief check for completeness of the reviews is made and the review details are transferred to a database. Reports are prepared for the Scheduling committee.

    6.  
  6. The Scheduling Committee meets about two weeks after all reviews have been received. Proposals are ranked by a weighted average of the ratings. The ratings are weighted using the individual referee averages and rms.

     The Committee groups all proposals into three categories based on referee ratings. Group A proposals are ranked very highly and are assured of telescope time. Group B proposals are mid-range. The Committee tries to schedule as many of these as available telescope time permits. Group C proposals are the lowest ranked, and generally do not compete strongly for telescope time.  The A, B and C rankings aim to provide a qualitative sense of how the proposal fared in the competition. 

    Although the Committee primarily follows the referee ratings for assignment of telescope time, an attempt is made to take into consideration unusual or extenuating circumstances arising in the review process such as instrument limitations or possible referee misunderstandings, and conflicts with other proposals.
     
  7. After the deliberations of the Scheduling Committee all proposal investigators are notified of the status of their proposals by email. This usually occurs about a week following the meeting
    .
  8. All proposals that have been granted observing time are placed into a queue for scheduling consideration (see Scheduling.Process)

 

Scheduling Process

The procedure we are following in the early operational phases of the GBT while capabilities are still being commissioned is outlined below. As given operational capabilities become more routine, this checkout process may be abbreviated, depending on specific circumstances.

All proposals which have been approved and granted observing time, go through a checkout procedure to determine the feasibility of observations before they can be scheduled.  As part of this process a proposal is placed into one of five queues or lists.

  • Awaiting Checkout  Once a proposal has been granted observing time it is placed into this queue.  All proposals start in this queue.  Movement of a proposal off this list indicates the start of the checkout process.
     
  • Active Checkout Proposals actively under investigation for feasibility of observations are listed in this queue. In cases where some or all of the proposed observations are feasible, the proposal will be moved to the "schedule" queue. If no part of the proposal is currently feasible (for example, they require a mode or hardware which is not yet available) then the proposal will be placed in the "on hold" queue.
     
  • Schedule  When some part (or all) of the proposal is capable of being scheduled, it is placed into this queue. Proposals remain in this category until either they are complete, or are returned to the "active checkout" queue (for those parts of the proposal which were not originally feasible).
     
  • On Hold This category is for proposals which have been checked for feasibility, and cannot currently be scheduled. These will be reviewed periodically, and returned to the "active checkout" queue to be reassessed when the required capabilities are made available.
     
  • Completed Proposals for which all allocated observing time has been scheduled and completed are placed into this list.

All of the queues are reviewed weekly to ascertain which proposals need and can be moved to another list.  The status of a specific proposal may be found in one of the five queues.

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