[Doomsayer]

Thought I'd round off this post by showing some installation photos at Magellan Observatory. I took the other near identical 12" f6.7 Ritchey Chretien CF truss OTA down there last thing in January. It now rides on a Losmandy GM200 mount in the Sirius dome.

For first light we balanced up the scope with a Canon 5D DSLR (thanks to Col) and took a few test runs of images at f6.7. This OTA also has an integrated field flattener. There was no vignetting visible but there appeared to be a slightly tilted imaging plane. I also put a 31mm nagler in the back for a quick visual check anyway - we were all blown away by the beautiful contrasty and sharp views - we did not expect this with such an imaging-biased telescope.

Next day we rechecked optical alignment with a 2" laser and a 2" autocollimator. The OTA optical axis & secondary mirror were slightly out - easily fixed. At nightfall we reinstalled the Canon 5D - the stars were now even right to the corners. We also installed the A-P 0.75x focal reducer with the 5D. Again, no vignetting, excellent contrast, and even stars across the field of the 5D. The FR did eat up more backfocus however.

I admit to being relieved, as the much smaller chip on my own 12"RC with an ST8XME is hardly a test of these RC's imaging performance.

Still a bit more opto-mechanical refinement to come perhaps, plus plenty more road testing. At least it has been proved worth the effort so far.

A couple more pics of the other new scope at Magellan Observatory are attached.

guy