Second shot at Homeyer TPoint

Went down and adjusted the polar alignment again as per last night’s TPoint model.

Started another 300 point run. Problem: about 30 points in, the system stopped with the message “Mount hit something or is unbalanced”. Drove down and checked – nothing was hitting the mount. Two possibilities:

1) The slight imbalance in the DEC axis is causing a problem.

2) It got cold – maybe the thing where the mount switches speed based on the temperature. Maybe I need to set the temperature limit a bit higher.

Restarted the big run. Did 311 points, with a raw measure of 72.7 arcsec.

Raw results for 311 points

Supermodel gives 6.1 arcseconds:

Supermodel results

Polar alignment now says: off by 67.4 arcseconds in Az (good enough), 75.0 arcseconds in Alt (excellent)

Re-run VCurves, since now I think I need more flux for the Canon. This avoids irregular stars, capturing seeing issues. Looks like 1 second exposures on a Mag 6 star gives 600K flux, reasonably consistent exposures in the log. Run 4 curves, 3 exposures per point, 50 steps per point. Best HFD is around 9. Sweet spot looks like it is 350 steps? Good Near HFD around 15.

Sample VCurve for Canon, Mag 6 star

OK, now that I have the big Supermodel, I tried several 2 minute and 5 minute exposures without guiding – using the ProTrack capability. PEC is running.

Some of the 2 minute ones work fine, but some show distinct elongation in the RA direction. 5 minutes always seem to show the elongation. Don’t see why it would sometimes be bad.

Installed Homeyer Cradle

Got the Andy Homeyer cradle installed. Oddly, the straps he sent were not quite long enough – short by a few millimeters. He sent out replacement ones, and I got everything installed. Had to make two mounting rails to hold the refractors – none of the existing rings and dovetails would fit. Balancing was tricky, since you have to get the cradle positioned right to get close to balance. You can’t really use all the holes in the Paramount Versa Plate, since the mount is in the way so you can’t get an allen wrench in to loosen/tighten the cradle adjustment screws. In the end, the scope is slightly off in DEC balance, since the two refractors are different weights. Maybe I will need to get some small weights for that balance adjustment. We will see how it goes. I tried running the scope a bit, and it doesn’t seem to be complaining.

I tried to get everything aligned; kind of tricky, since the Telrad doesn’t fit for now. When the Tak is mounted on the cradle, the Telrad would be in a bad position where it would hit the pier. I played for awhile, thought I had things aligned, then tried to do a TPoint run. Didn’t work, the Pinpoint solutions were all failing.

Tonight, I found that things seem to be completely incorrectly aligned. Worked some more on it; Regulus seemed to be a good star to use, I can tell if I have the star (Reggie has a small buddy next to it). Finally got things aligned correctly. Guide scope focused, C11 focused, ready to go. Finally got AAG to pinpoint solve, started a big run for TPoint.

I assume PEC doesn’t change as a result of the cradle.

Also – established a new Park position. The refractors have switched sides, so now I have Park so the scope is fairly close to the Home position.

Ran a big (305 point) TPoint run, raw results are 220 arcseconds.

Supermodel results:

Hmmm, I notice it now thinks the polar alignment is a bit off. Maybe tomorrow I will play with that. I suppose it could have shifted a bit with remounting the telescopes.

Tried a 2 minute exposure, no guiding, with ProTrack on. Looks pretty good. Try 5 minute – looks pretty good!