July 26, 2006
ALMA Pointing
6
Optical Pointing Telescope
±NRAO Design
±4-inch Refractor
±IR (l > 700nm) and clear focus correction filters
±Rolled-Invar Tube
±COTS CCD/Frame Grabber
±EPS = 1.1 arcsec per pixel
±FOV = 12x9 arcmin
±Sensitivity > 7th mag in 5 second exposure
¥Designed and built by Antenna Group in Tucson.
¥Based on OPT used on NRAO 12m.
¥Minor problems were:
¥Focus shift with temperature change.  Likely from lens cell.
¥CCD nonuniformities.  Confused peak finding algorithm.
¥Analog CCD output.  Digital less complicated.