center.pro
This script centers the telescope at the pixel coordinates defined by the procedure zcenter.pro.
usage: center xpix ypix
xpix and ypix are the current pixel location of the object to be centered. Scale is the current scale in arcsec/pix (you need to change this value when switching between cameras in OSIRIS), and rotator is the instrument rotator angle in degrees.

zcenter.pro
Use zcenter to zero point the center.pro parameters, xcen, ycen, scale, and rot. These are the desired object pixel position (e.g. slit center), scale in arcsec/pix, and rotator angle in degrees (default 272 for the 4m and 0 for the 1.5m). These are also used by slitscan.pro. All variables are global, so this script need only be run when changing the observing setup.
usage: zcenter xcen ycen scale rot

do_grid.pro
This script will take an MxN grid of images with arbitrary offset in Ra and Dec. The user is queried for the offset values and grid dimensions. do_grid is available on system startup.
usage: do_grid
Click here to see the Prospero script.

slitscan.pro
This script will take a series of spectra along the OSIRIS slit. The script will use the rotator angle (slit position angle) defined by zcenter.pro so that it can step stars along the slit at arbitrary slit orientations. The procedure begins with the object centered on the slit and returns to the center position. Each object spectrum is typically sky subtracted by a median combination of all the scan spectra. slitscan is available on startup.
usage: slitscan step nimages nscans
where step is the amplitude in arcsec between each spectrum in the scan, nimages is the number of spectra taken along the slit, and nscans is the number of complete scans. Click here for the Prospero script.

abbaper.pro
This script will take a series of spectra in the object-sky-sky-object mode (ABBA). The two sky positions are symmetrically placed on either side of the slit (i.e. off the slit). The procedure begins with the object centered on the slit and returns to the center position. abbaper is available on startup.
usage: abbaper step nscans
where step is the amplitude in arcsec off the slit. nscans is the number of complete abba scans. Click here for the Prospero script.

abbans.pro
This script will take a series of images in the object-sky-sky-object mode (ABBA). The sky position is placed "step" arcseconds north (positive) or south (negative) of the object. The procedure begins with the object centered and returns to the center position. abbans is available on startup.
usage: abbans step npairs
where step is the offset in arcsec and npairs is the number of complete abba sets. Click here for the Prospero script.

please mail questions or comments to: Bob Blum (rblum@noao.edu). rev 03 Feb 2000.