README Template 73.1 (please do not delete the README Template Version line!) ESO Programme ID: 073.D-0652(B) Principal Investigator Name: Guido De Marchi Principal Investigator E-mail Address: gdemarchi@rssd.esa.int Principal Investigator Telephone Number: +31 71 565-8332 Principal Investigator Postal Address: European Space Agency / Science Communications Service / Keplerlaan 1, SCI-CC / 2200 AG Noordwijk / The Netherlands Instrument: NACO OPC Priority Class: A OPC Approved Total Execution Time: 9.0 Estimated Total Execution Time (including overheads): 1.0 README File Submission Date: 10.03.2004 Programme Description ===================== General Overview ---------------- This is a programme aimed at detecting the white dwarf cooling sequence in the globular cluster M4. Part A of the programme will use NACO to look for these cooling objects in a field identified on the basis of available HST data. Part B of the programme, described here below, is a test run lasting one hour to verify that the appropriate reference star has been selected the for adaptive optics. This test run is needed in light of the relatively crowded region in which observations are to be executed. N.B. Using available high resolution HST images of M4, taken in the near-IR, we have selected a region of the cluster where the dithering pattern that we propose is sufficient to efficiently subtract the effect of the sky. We, therefore, do not need to take sky comparison fields at large offsets. VERY IMPORTANT NOTE ------------------- We understand that in the course of Period 73 the ALADDIN detector of Conica could be replaced with a new one. Since the test run described here (part B of the programme) is meant to verify that the proposed observing strategy is adequate for the deeper observations which form part A of our programme, it is essential that they are both taken with the same instrumental setup, including the detector. If this is not the case, then we may be forced to devote more time to a second test run with the new detector, which could eventually prevent us from reaching the stated science goals. We do not have a specific requirement as to when, in the course of Period 73, this proposal should be executed, although visibility might favour an early stage (possibly May and June) for the test run. However, from the time when part B of the programme is executed and the data are made available to us, we need at least two weeks to properly process them and validate the observing strategy. Only then will we be able to proceed with the deeper observations of part A. If it is expected that the new detector will be fully operational and calibrated by the end of May, then it might be advisable to wait until then to execute the test run (part B), with part A following in due course. If, on the other hand, the detector's installation could slip into July or later, then it would be wiser to begin with the test run (part B) at a very early phase of Period 73, possible as soon as seeing conditions and scheduling allow, so that also part A could be possibly concluded before the detector is replaced. Since we do not presently know whether and when the NACO detector will be replaced, we cannot presently provide effective timing constraints for this programme. Therefore, we must leave it to the best judgment of ESO's User Support Group and Scheduling Team to guarantee the necessary continuity needed for a successful execution of this programme. Approved Waiver Request Summary ------------------------------- Not applicable Critical Observing Condition Constraints ---------------------------------------- Excellent seeing (<0.6") and photometric conditions are needed, as requested and approved in Phase I. Time Critical Aspects --------------------- Please see "VERY IMPORTANT NOTE" above. Special Calibration Information ------------------------------- None ToO Information --------------- Not applicable Pre-Imaging Requirements ------------------------ Not applicable, as this part of the programme is, in practice, pre-imaging. Source of preimaging: Not applicable. OB Information ============== List of Science OBs ------------------- (for ISAAC imaging, please indicate the magnitude of the brightest star in the field for each OB) Total Number of Submitted Science OBs:1 M4_test_H_J Brightest target: H=14.5 Brightest target: J=15.2 Reference Star : V=13.3 Please note that the brightest object is always the reference star (R1), which will normally be placed about 5" off the edge of the NACO S13 FOV. The observing strategy will unfold as follows: The target field, located 12" N of the reference star R1, is acquired and a series of eleven images are taken in the H band, each of duration DIT=115 s, using a suitable dithering pattern. The telescope is then slewed 12" S, to the reference star R1, which is imaged 26 times in the H band, with an exposure time of DIT=0.6 s, and twenty times in the J band, with an exposure time of DIT=1 s. A suitable dithering pattern is applied between exposures and use is made of the neutral density filter. Subsequently, the telescope is slewed back to the main target, located 12" N of the reference star R1, and a series of four dithered images is taken in the J band, each of duration DIT=300 s. Although the availability of previous HST/NICMOS of the target field will make it easier to obtain an accurate photometric calibration without the use of spectro-photometric standard stars, experience shows that imaging periodically the reference star will provide a better characterisation of the PSF, eventually resulting in a more reliable reduction of the NACO data. List of Calibration OBs with Associated Science OBs --------------------------------------------------- Total Number of Submitted Calibration OBs: 0 None OB Compliance Checks ==================== (Y = Yes, N = No, NA = Not Applicable) Do all your OBs comply with the instrument specific requirements listed on the instrument specific Phase 2 Web pages ? [Y] Do all your Finding Charts comply with the both the general and instrument-specific finding chart requirements? [Y] If you submitted OBs for standard stars, did you specify the magnitude and spectral type of all standard stars ? [NA] Have you included OBs for any calibrations that you need but which are not a part of the Calibration Plan? [NA] [UVES only] Do all your UVES OBs use only the allowed templates listed on the UVES Phase 2 Web pages ? [NA] [ISAAC only] Did you indicate the magnitude of the brightest star in the field for ISAAC imaging observations? [NA] [ISAAC only] If you submitted OBs for standard stars, did you use the provided StandardStar templates? [NA] [FLAMES only] Did you specify the hour angle range for which your Target Setup files are valid ? [NA] [VIMOS only] Did you specify suitable guide stars for all your OBs using Guidecam? [NA] [VIMOS only] Did you check that the chosen guide stars are suitable for all the offset positions and that they do not produce unacceptable vignetting of the field of view? [NA] [MIDI only] Did you indicate for each science star OB the corresponding calibrator star OB name in the ReadMe file as well as in the comments of the OB ? [NA] [MIDI only] If you use calibrator stars which are not in the CalVin database, did you specify their characteristics in the ReadMe file and in the OBs ? [NA] If you answered "NO" to any of these questions, please revise your OBs *before* submission.