Other
Scientific paper
Jul 2002
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2002hst..prop.9656d&link_type=abstract
HST Proposal ID #9656
Other
Hst Proposal Id #9656
Scientific paper
A moderately crowded stellar field, located 6' West of the centre of the cluster 47 Tuc, is observed repeatedly {every three weeks with the WFC, every other month with the HRC} in various filters, spending 1 orbit per epoch. Different filters will be used every time, so that over the course of the year all filters will have been employed at least twice. The most common filters will be checked more frequently. The same field has been observed in the course of the SMOV phase and the positions and magnitudes of the most prominent stars have been accurately measured. Although the field is neither a proper astrometric nor a proper photometric standard one, the positions and magnitudes of the objects in it can be used to monitor any local and large scale variations in the platescale and sensitivity of the detectors. It should be noted that for the filters which have already been used during the SMOV phase it will be sufficient to take one single image, without CR-SPLIT, since the exposure time is always short {20-30 sec} and there will be so many stars that the few of them which are affected by cosmic rays can be discarded as outliers in the photometry. For narrow and medium band filters not exercised on this target in the SMOV phase, however, a baseline will have to be set. This expenditure of time will apply to the current cycle only. At variance with the approach used in SMOV, there is no need for large telescope slews to place the same objects on opposite sides of the detectors, thence allowing the programme to remain compact and efficient. All exposure level parameters are set to their default values, except for the amplifier gain of the WFC exposures in the F606W band, which will be collected with the gain value of 2 for the WFC for compatibility with the SMOV observations. The exposure time is typically 30 seconds for the WFC, 60 sec for the HRC. No attempt will be made to attain a predefined or the same orientation on the sky amongst different epochs. Typically, for the WFC, five exposures will be accommodated in one orbit. For the HRC, about 10 exposures can be fitted within one orbit.
No associations
LandOfFree
Stability of the ACS CCD: geometry, flat fielding, photometry does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Stability of the ACS CCD: geometry, flat fielding, photometry, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Stability of the ACS CCD: geometry, flat fielding, photometry will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-733763