Un-pin the pod, take screws out by 3/4 inch
Find star near zenith, not too bright. Put in center of TV.
Change the /Realtime/lib/set.dat file to have 5000 for the first 4 items (leave the other two alone).
Start up "go4col" instead of go4.
First find the rough correction for Coma by using the tilt command, move the star on the sky in the opposite direction of the narrow or bright part. Change the focus occasionally to check that the secondary obstruction is centered on the pupil. Because there is backlash, always come to the final position from the same direction.
Now we need to refine the coma, and correct for astigmatism by bringing the secondary axis on the same axis as the primary by tilting about the neutral point, using the "neutral tilt" command. This is done using Brian McLeod's program "aberfit", itself based on a commercial software by Roddier.
Move the telescope to a star at about Dec=+65, HA=-1 hour. This is so that you do the final alignment in a part of the sky where you can get to the pod to pin it. If it takes too long, you may have to move the telescope to a new star at some point.
Add the following to your path: /home/bmcleod/bin /home/bmcleod/starbase/bin
Add the following to loginuser.cl (or login.cl)
reset collimate = /home/bmcleod/Fit/ task $collimate.pkg = collimate$collimate.cl
Start up iraf as usual, and cd to the data directory. Load "collimate". Take a focus frame, in the V fitler say, and determine the best focus, F. Now take two ~20sec exposures with focus settings F-200 and F+200. Call these m200 and p200 respectively.
Make sure you have an imtool running (e.g., saoimage). Then to run,
cl> collimate co> aberfit 00xx.m200.fits 00yy.p200.fits 200
This program will display the 4 extensions in the imtool in the order 1,2,3,4 (bottom right, bottom left, upper left, upper right). Remember where the center of the focal plane is for each of these extensions (upper left, upper right, lower right, lower left, respectively). In each of these mark two stars with a space bar which are about the same distance from the focal plane center, and which are fairly far away from that center and far away from each other. These two stars should be well-exposed. After each pair, type "n" to move on to the next extension. After the second star in the 4th extension, type "q".
The program will churn a little now, and give out the corrections to be applied, in a format that can be cut and pasted into the rtshell window.
You should do this at least 3 times, until the corrections are small. Now it's time to pin the pod.
Find a star in the TV, set up the TV in the dome so that you can see it from the ladder. Now pin the pod, screwing opposite pins until you see the star move. Try to keep the star in the same place.