For initial collimations, use a globular cluster from the starlist 
/kroot/starlists/ESI/globulars.  These have accurate centers determined
from the DSS, and are easier to tweak up pointing on than bright stars
or other types of fields.  You hopefully can distinguish a gradient in
the star density.  Follow this gradient to the cluster center and set
the collimations at that point.

Find any reasonably bright star and send to the nominal REF pointing 
origin for ESI. If necessary, center using the hand paddle.

(a) Determine the TVFLIP.

Note the orientation of the tkrose for the guider.  If the azimuth arrow
points 90 degrees CLOCKWISE from the elevation arrow, this will be called 
left-handed.  If it is 90 degrees COUNTERCLOCKWISE this will be called
righthanded.

Move the telescope in elevation by -10 arcsec.  The star will move along
the positive elevation direction.
Move the telescope in azimuth by -10 arcsec.  The star will move along the
positive azimuth direction.

Compare the observed handedness with the tkrose handedness.  If they
differ, use "show -s dcs tvflip" to check the current handedness, and
change it.  If you have to do this step, you must reselect the instrument,
kill and restart the tkrose.

(b) Determine TVANGL.

With the rotator at ROTPPOSN = 0 in STATIONARY mode,
place the star near the middle of the guider.  Save a 1x1 guider frame,
move the telescope -10 arcsec in elevation, and save another 1x1 guider frame.
Measure the positions on the guider frames and calculate the rotation.

Need the math in here, and a check on whether these are being done in the right order.

(c) Determine ROTZERO.

ROTZERO for ESI is defined such that North is up on the detector when
ROTPOSN = 0.

(d) Determine the guider pointing origin.

(e) Measure the guider scale.

(f) Check guiding and centering in PA mode, vertical angle mode, and
    stationary mode.