Find any reasonably bright star and send to the nominal ESI pointing 
origin for ESI.

(a) Determine the TVFLIP.

The following assumes that the guider orientation (TVFLIP) has been
checked.

Image a field on the guider, then with ESI.  Compare the handedness
of the two images.  If they differ, change the sense of INSTFLIP.
(Type "show -s dcs instflip" to determine the current setting.)

Kill the instrument tkrose and restart it.  Confirm that it now has
the correct handedness.

(b) Determine INSTANGL.

With the rotator at ROTPPOSN = 0 in STATIONARY mode,
place the star near the middle of the imaging field.  Save a frame,
move the telescope -10 arcsec in elevation, and save another 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.

Place a star near the center of the imaging field and take an image.
Move the telescope nearly half the field with South, and take another
image.  Measure the (x,y) positions of the star in both images and 
calculate the angle from "up" on the detector.

(d) Check operation of INSTXOFF and INSTYOFF.

Take an image with ESI.
Type "modify -s dcs instxoff=120 rel2curr=t" and take another image.
The star should have moved -120 arcsec in the x direction.
Type "modify -s dcs instyoff=120 rel2curr=t" and take another image.
The star should have moved -120 arcsec in the y direction.

(e) Measure the imaging scale.

A quick estimate: take an image, move the telescope 100 arcsec, then
take another image.  Measure the (x,y) coordinates and calculate the
arcsec/pixel from that.

A more sophisticated measurement may use astrometric doubles, an astrometric
field, or may calculate the full distortion map (where the scale is only
the first order term in the distortion).