ING Wide Field Imaging Survey


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Observations beginning Semester 2001A (February 2001)

During the spring of 1997 the Wide Field Camera (WFC) was commissioned in the prime focus of the 2.5-meter Isaac Newton Telescope on La Palma. The WFC 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 ING Board (formerly 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.

The first call for proposals resulted in five programmes being awarded time under the umbrella of the ING's Wide Field Survey (WFS) programme. These ran for the period August 1998 to January 2001. Details and links to these programmes are available at In view of the success of the initial WFS period, the ING Board has recommended the continuation of this survey programme.

Rules for applications

This 2nd 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 2001A, and spanning a period up to three years. A review of progress is foreseen annually, on the basis of which further observing time will be granted. No specific limit is set to the amount of observing time that may be requested, but the ING Board have stated that approximately five weeks per semester (covering dark, grey or bright time) will be available for the WFS.

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. Applications to continue or modify existing WFS programmes are permitted.

Final selection will be based on scientific merit (including potential additional uses of the data), 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 - see the CASU/ ING WFS pipeline description), through the ING WFS archive. Hence the usual one year proprietary period will not apply to data obtained through this Announcement of Opportunity.

The review of the submitted proposals will be carried out under the auspices of the UK PATT and NL NFRA Programme Committee, by a panel whose composition will be decided by them.

The results of the review process are anticipated following the meetings of the panel in December 2000.

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

How to apply for time

The following details have to be supplied in the application, which should be laid out on no more than six 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

Pages 2 and 3:
Detailed science case. The applicants should note how the proposed work will relate to and improve or enhance existing or proposed surveys with other facilities. Any possible additional uses of the data should be highlighted.

Page 4:
Figures & references

Page 5:
Technical description which must include:

(i) feasibility,
(ii) specification of target magnitude limits, and justification of required number of (dark, grey, bright) nights.

Page 6:
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 the ING PATT Technical Secretary(Dr Ian Skillen: ( . Proposals should be submitted in Postscript, LaTex or ASCII text formats only. Any accompanying figures should be supplied in PostScript format. Figures should be sent by email as individual messages with the PI, Proposal title and Figure number clearly indicated in the email Subject line.

A confirmation of receipt shall be provided to the PI.

Deadline for submission is Midnight (UT+1) 30 September 2000.

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

The chips are thinned and have excellent QE performance. [For details on QE and CCD Characteristics see the CASU/ING WFS pages.]

Full technical information on the INT-WFC is available at the CASU/ING WFS pages

WFC broad-band detection limits

Limiting magnitude estimates for a 600 sec exposure through the sloan-gunn filters are given in the following table, assuming a dark sky and a median seeing of 1.0 arcsec.

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


The current cycle time of the mosaic between exposures is 55 seconds (of which 30 seconds is readout). During this time the telescope can be slewed and autoguiding started, hence the readout time determines the deadtime.

The sloan-gunn and harris broad band glass filter sets are available for the WFC plus a KPNO-type B-band filter. The Stromgen u,b,v,y set plus a number of narrow band filters are also available. Full details on filter lambda, FWHM, peak transmission can be found on the ING WWW site at

The original Semester 1998B Announcement of Opportunity is available for reference.

further details may be obtained from the ING WFS project manager, Dr. N.A. Walton (

This page last updated: 24 July 2000