Astronomy and Astrophysics – Astronomy
Scientific paper
Jul 2006
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2006acs..rept....5w&link_type=abstract
Instrument Science Report ACS 2006-05, 13 pages
Astronomy and Astrophysics
Astronomy
Hubble Space Telescope, Hst, Space Telescope Science Institute, Advanced Camera For Surveys, Acs, Apsis, Relative Astrometry
Scientific paper
The log files from APSIS, the ACS science team’s image processing pipeline, have been analyzed to determine the relative astrometric scatter among ACS images observed within a single visit. For a sample including more than 200 visits, approximately 2% of the visits are found to have images with alignment shifts greater than half an ACS WFC pixel (0.025 arcsec); more than 25% of visits include exposures with shifts larger than 0.25 pixels (0.0125 arcsec). Observations taken in 2-gyro mode are slightly more likely to show 0.25 pixel offsets. The typical offset size drops dramatically if only exposures taken using the same filter are compared: only 3.5% of visits include exposures with shifts larger than 0.25 pixels, and 1.1% have shifts larger than 0.5 pixels. Half-pixel or larger shifts result from the failure to acquire two guide stars, from (apparently) bad guide stars, and when the ramp filters are used. These shifts should be corrected to produce the highest-quality combined images, especially if images taken in different filters are to be accurately aligned.
No associations
LandOfFree
Relative Astrometry Within ACS Visits 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 Relative Astrometry Within ACS Visits, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Relative Astrometry Within ACS Visits will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1136298