Starting spring re-assembly

After a hard winter, we have finally had some clear nights with reasonable temperatures, and on evenings that I’m free, so I’m finally getting back outside. I have a bunch of work to do putting things back together and back on the air.

Re-assembling the optics, I have an AT8RC 8″ Ritchey-Chretien mounted on the G11. The AT reducer/flattener was not working well – bad distortions – and I read multiple reviews online about this device having some design problems (and apparently being recalled), so I removed it and am working direct for now. The camera is a QSI583WSG.

Saturday night was about connection and focusing, and generating the “to-do” list.

There are two cameras (main and guide) both connected via USB, and two USB-to-serial convertors for the focuser and mount, and I couldn’t get the connections to work. Maxim/DL was hanging badly any time I tried to do a Connect for the cameras. Hunting online, I found reports that the QSI camera is incompatible with certain drivers for USB-to-serial convertors, and that the fix is to re-install the convertor driver AFTER the camera driver is installed. I don’t know why that should work but I tried it and it did.

Next, focus. Taking the focal reducer out of the train meant the focus spacing was different so I had to spend a couple of hours experimenting with different spacers until I was able to get the focus in range of the Feather Touch focuser. Then I needed a couple of hours to gather new V-Curves for the focusing software and, finally, got things into focus.

2011-04-02-M13-110x1024To end the evening I took a test image of M13, which is starting to rise in the East in the late evening. I have no flat frames yet, so the image shows some vignetting.

Some notes on things to tackle in future evenings:

  • Collimation is off
  • Guide camera isn’t focused very well
  • Guider calibration not working well (I suspect cables and connectors since it was able to calibrate with pulse guiding but not with camera guide relays)
  • Periodic error needs attention – I’m getting elongated stars at the high focal length of the AT8RC even with guiding, and the oVision worm in the G11 should be able to do better than this. Some adjustment needed; I’ll re-check polar alignment, then adjust the worm, then program a new PEC curve.

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