TRACKING/FLEXURE THROUGH ZENITH

1. Point to a field 45 min. East of meridian, Dec. +17 (within 1 degree). 
The field should have at least two stars relatively close together, but not 
so close as to confuse guiding. One star will be used as a guide star.

2. Start guiding on one star. Set a secondary period of every 10 frames, 
and subframe by typing "winsiz xxx yyy" and "winloc xcen ycen." 
"winsiz xxx yyy" sets the subframe window size in pixels, and "winloc xcen ycen" 
sets the subframes center. The subframe should contain three or more stars, 
and may include the guide star itself.

3. Start taking images with the science detector.

3. Stop guiding and taking ESI images when the star reaches an HA 0:30 W.

4. Record guider frame numbers and ESI frame numbers for further analysis.