Next: FIBER CABLE SELECTION
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Up: SUGGESTIONS FOR CREATING THE TARGET FIELDS
- At least 2 Field Orientation Probes must be assigned in order
to ``lock" the telescope onto the target field.
We suggest, however, that 3 or more probes be assigned (1 near field
center, two near the edges of the field) to provide
redundancy and to serve as a check on astrometric ``goodness"
and other possible fiber placement errors.
- Since assignment to a field orientation star can impact the
assignment of fibers onto neighboring target objects, select
several times more potential field orientation stars than are
needed and let the assignment routine find the ones that have
the smallest impact on neighboring fiber assignments.
- The stars selected for use by the Field Orientation Probes should
fall in the magnitude range between m=10-15.
(If there are clouds and/or the seeing is larger than 1 arc-second,
stars fainter than 15th may not be visible with the
FOPS TV camera.)
- If possible, keep the range in magnitude of your FOPS sample to
2 magnitudes or less so that the intensity of each star falls
within the dynamic range of the FOPS TV camera.
- Make absolutely certain that the stars selected for use by
the Field Orientation Probes have good astrometric solutions
and were used (or measured) within the same solution as the
target objects (ie. same zero point reference).
Be careful of possible proper motion problems (ie. don't use
old plates or catalogs).
You must account for proper motion effects as our astrometry
routines don't compensate for proper motion.
Reject any stars with large uncertainties in their coordinates.
REMEMBER THAT THESE STARS ARE BEING USED TO LOCK AND GUIDE
ON YOUR TARGET FIELD!
Tue Aug 29 16:45:05 MST 1995