CFH12k Queued Observing Programme: Preliminary Description.


2. The Proposal Process.

 Two proposal tiers will be used. First, a near-conventional proposal oriented around the scientific justification to be submitted to the TACs, and second, a description of the accepted observing programme providing all the information required to execute the programme by the observing queue.

2.1. First Tier

The first tier proposal will be based on the current observing proposals used at CFHT, but with refinements required for queued observing. The purpose of the first tier proposal is to establish a scientific priority for each observing programme and to set guidelines for the amount of I-time which should be allocated to the programme. (I-time is defined as time at the telescope under a dark sky with the camera shutter open. This does not include overhead associated with telescope pointing, camera readout time, etc. See Appendix 1)

Investigators will be asked to provide all the usual information required by CFHT proposals, including a general scientific justification for the programme. It is the responsibility of the Technical Assessment and TAC to ensure that the requested I-time is appropriate. The TAC may grant less I-time than requested.

Based on this information, the TAC will then provide:

    1. The maximum total I-time to be expended for each proposal.
    2. The relative rank of each accepted proposal (which will be normalised to unity for each TAC)
    3. The number of nights to be allocated to the queued observing programme from the given TAC's allotment of available time. (Items 1 and 3 are clearly related. The TAC will be provided with an estimate of the observing efficiency, in terms of the fraction of a night which may be put into I-time, which they may use to determine item 3 based on the sum of item 1 across all proposals. We expect this factor to be greater than 70%, see the document "Sample Tier 2 Proposal" for an example.)

      The first tier proposal will require a little more effort on the part of the investigators and the TAC than is currently the case. The investigators must be careful to explicitly describe the total open-shutter-time requirements of their proposals. CFHT will provide some standard methods of estimating this for different field depths and sky conditions. The TAC will also need to assess the amount of I-time required to successfully complete each project, and whether or not this matches the investigator's requested time.

2.2. Second Tier

 The second tier proposal is an explicit statement of each accepted programme's needs. This takes the form of a set of keyword/value pairs assembled by each investigator which completely describes the needs of his or her programme and which defines the use of the I-time as allocated by the TAC. CFHT will provide the mechanism by which the investigator will compile the required information - a set of web forms and/or ASCII templates. CFHT will also develop a database engine which will parse the provided information into a database on the front end and will be capable of identifying, from this database, the small set of optimum observations to be taken at any given time once the observing queue is started. The submission mechanism will allow for the grouping of observations when appropriate.

Following is a list of the information which will be required for each programme in the second tier proposal:

      1. PI & CoI names & contact information
      2. Project ID, title, description
      3. Field description (coordinates of centre, non-sidereal tracking, preferred guide star)
      4. Observational constraints for a field (maximum sky brightness, maximum airmass, requested seeing range, photometric conditions)
      5. Instrument configuration (filter, raster, binning factor)
      6. Photometric calibration requirements (precision, number, preferred fields.)
      7. Instrumental calibration requirements (dome flats, twilight flats, superflats.)
      8. Preferred observation grouping - indicating which observations should be obtained together.
The investigator may specify that some exposures, of the same field, be obtained together. This is to avoid the circumstance by which one programme interrupts another which is already under way when the current programme requires more exposures of the same field. This will aleviate some of the ineffiency due to repointing the telescope (although exposures within a group may be dithered for purposes of generating data for a superflat). For the purposes of establishing the viability of a group, exposures listed within that group will be treated as a single exposure of total integration time equal to the sum of the individual exposure times plus their readout and instrument reconfiguration overhead. Thus a group is not started unless there is sufficient I-time remaining within the night to complete that group. This also encourages investigators to specify groups of minimum length.

The final format will be formalised so that it can be handled automatically and will include considerable detail not described here. We propose to adapt the HET phase II proposal language (Gaffney, 1997, private communication, and http://rhea.as.utexas.edu/~niall/adass97/) to this programme.



Web conversion by: Dr. T. M. C. Abbott, tmca@cfht.hawaii.edu
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