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2004.12.28 Went over to Bob's tonight and fiddled around with the Series IV some more. We were going to try to get the focus as close as possible with the Ronchi grating and then switch out to the knife-edge accessory and see if we could find focus that way. However, before we got to that point, Bob had the idea to take the back end of the Series IV off and just look through the back end of the modular mount. There was some mention in the manual that this was possible. When we did this, I was able to see down to a region around 1-bar on both sides and then it got dancy again. Focusing to the center of this region was reasonably easy since it was so thin, and the image results showed round stars that were as big as the seeing was bad. So I think we can actually use this thing now and take proper prime focus shots! We also did a series of Hartmann mask exposures with the 100mm lens to figure out where the focus point was, but after doing the series and trying to replicate the proper focus point, the image came out blurry. Not sure what the problem is with that yet, but I need to get it working because it is the lens I want to use for the Pleiades/Machholz conjunction on January 7th. |