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Aug 98 to Jul 2000

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During the spring of 1997 the Wide Field Camera was commissioned in the prime focus of the 2.5-meter Isaac Newton Telescope on La Palma. This new instrument offers unique opportunities for the UK/NL communities to execute high resolution, deep, wide field optical imaging surveys.

At its meeting in October 1997 the Joint Steering Committee considered ways to stimulate the use of the INT Wide Field Camera for survey programmes. The committee reflected on the changing role of the INT in the era of the 8-meter class telescopes. It considered the INT ideally suited for programmes of target selection for later follow-up study with large telescopes, and for larger scale survey programmes with a clear scientific goal in their own right.

In view of the shift in emphasis of the role of the INT, and given that Gemini-North/South and ESO VLT will come on-line in the near future, the Joint Steering Committee wishes to promote the use of the INT Wide Field Camera for large scale survey work. It will make available substantial amounts of observing time (three or more weeks per semester) for high quality survey programmes, and therefore releases this Announcement of Opportunity to apply for observing time with the INT Wide Field Camera. This observing time will be allocated independently from the existing time allocation committees such as PATT, the NL TAG, and the CCI International Time Projects.

Ground rules for applications

This Announcement of Opportunity makes available substantial amounts of observing time with the prime focus Wide Field Camera on the Isaac Newton Telescope. The announcement is intended for a small number of large scale survey programmes which would normally be beyond the scope of the bi-annual time allocation system. Observing time may be spread over more than one semester, starting during semester 98B, and spanning a period up to three years.
Review of progress is foreseen after the first year. No specific limit is set to the amount of observing time that may be requested, but it is expected that of order three to four weeks per semester will be available.

Applicants may wish to set up collaborations between research groups in order to generate the widest possible interest in the proposed survey, or combine various science objectives within the survey programme definition. Equally welcome are proposals that have a well focussed single scientific objective.

Final selection will be based on scientific merit, timeliness, and technical feasibility of the proposed observations. Proposals must fall outside the remit of the bi-annual time allocation process. The planning and scheduling of the observations will be carried out in conjunction with ING project staff, in order to best maximise the efficiency of the survey.

The data will immediately be made available to the UK and Dutch research community in semi-processed form, and later fully processed (i.e. astrometrically and photometrically calibrated), through the ING archive. Hence the usual one year proprietary period will not apply to data obtained through this Announcement of Opportunity.

An international team of experts will advise the Joint Steering Committee on the scientific merit and relative priorities of the submitted proposals. The Joint Steering Committee is not bound by this announcement to allocate any time in case it receives no suitable proposals. Likewise it may merge proposals where a strong scientific benefit will result.
A decision by the Committee is anticipated following its meeting in May 1998.

This announcement is open to PIs currently working in the United Kingdom and the Netherlands only.

Further details on how to submit proposals, and technical details are presented below.

How to apply for time

The following details have to be supplied in the application, which should be laid out on 5 pages as described below:

Page 1:
Title of proposal
Name of PI and affiliation
Names of CoIs with affiliation
Postal and email address of PI
Summary of proposal (max 200 words)
List of targets with filter passbands & exposure times

Page 2:
Detailed science case

Page 3:
Figures & references

Page 4:
Technical description which must include

(i) feasibility,
(ii) specification of target magnitude limits, and justification of

required number of (dark, grey, bright) nights.

Page 5:
Plan for data analysis and description of how the data will subsequently be used. This should include a list of individuals on the project and their role.

Proposals should be sent by electronic mail to Dr. N.A. Walton:, in ASCII text, LaTeX, or PostScript format. Accompanying figures should be supplied in PostScript format.

Deadline for submission is 15 March 1998.

A confirmation of receipt shall be provided to the PI.

Technical background

The INT Wide Field Camera holds four thinned 4096x2048 pixel EEV CCDs with a pixel size 13.5 micron which projects to 0.33 arcsec on the sky.
The chip layout in the focal            111112222233333
plane covers an L-shaped part           111112222233333
of the sky, where the outer             111112222233333
perimeter has a length of               111112222233333
34 arcmin. The diagram to               111112222233333
the right indicates how the             111112222233333
four chips are oriented.                4444444444
The total area covered is               4444444444
0.27 square degree.                     4444444444

[NB: the availability of CCD #3 is not presently known, in which case the imaging area will be 0.21 square degree with only CCDs 1, 2, and 4]

The chips are thinned and have excellent QE performance. [For details on QE see Spectrum No. 15 Sep 1997 page 20] Limiting magnitude estimates for a 10-15 min exposure are given in the following table, assuming a dark sky and a median seeing of 0.7 arcsec. [For 1 arcsec seeing subtract 0.4 mag, or for 1.5 arcsec seeing subtract 0.8 mag.]

WFC broad-band detection limits

      Bands    5 sigma limit    1 sigma SB limits  Exposure Time
                   (mag)          (mag/sq arcsec) 

        U          24.75             26.6             700s
        B          25.75             27.6             600s
        V          25.25             27.1             600s
        R          25.00             26.8             775s
        I          24.25             26.1             850s
        Z          22.50             24.3             600s

Maximum practical exposure times assuming gain of unity and taking into account the sky brightness in the different bands are:

WFC broad-band sky 30k counts/pixel times (seconds)

Moon phase: dark grey bright

        U         ----    6300      400
        B         ----    8300     1200
        V         ----    6900     1900
        R         4300    3300     1700
        I         2700    2300     1400
        Z          700     600      500

The readout time of the mosaic (after soon to be implemented controller upgrades) will be some 120 seconds. During this time the telescope can be slewed and autoguiding started, hence the readout time determines the deadtime.

A UBVRIZ broad band glass filter set is available for the WFC plus a KPNO-type B-band filter. Available narrow band filters are OIII and H-alpha, plus Stromgen u,b,v,y. Full details on filter lambda, FWHM, peak transmission can be found on the ING WWW site at

further details may be obtained from the WFC instrument specialist, Dr. N.A. Walton (

This page last updated: 20 January 1998

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