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Optimizing the "As Delivered" Telescope I was very happy with the telescope as delivered from Obsession. I have only done a couple things that I would consider as basic changes to the telescope, one of them was smart. :-) Opening up the Tube BlocksBecause I live in a pretty harsh desert environment (very low humidity), I had to open up the tube block holes just a bit with sand paper so that the tubes would go in. They still fit very snugly after this modification, and I'm hesitant to sand the holes further as I know I'll have this telescope a long, long time and with wear, the holes will enlarge themselves. This modification helps a lot when my fingers are cold, and I'm trying to twist the truss tubes out of the blocks for pack up. Shortening the Truss TubesWhen I got my telescope, I found that I couldn't quite reach focus with my 22 mm Nagler. (Read all of this section BEFORE attempting to cut your truss tubes!) After searching the Yahoo Obsession Users group, I came to the conclusion that I would need to shrink the optical path length by a small amount. I trimmed the height of by truss poles by 0.25" with the best pipe cutter that I could find at the local home improvement store. I took my time, measuring each pole twice and then notching the poles carefully before really cutting them. The ends came out smooth, but the insides of the tube were a bit sharp. I used a medium grit sandpaper and they are now completely smooth on the inside so even my son can stick his finger in them and not get cut. After all of this 'measure four times, cut once' work, I could indeed reach focus. I was happy, life was good. THEN I found out that I had been hasty in my assessment of options. I found that the mirror collimation bolts were nearly all the way out, and that I could have easily reduced the optical path length by 0.25" by just turning these inward by the right amount. I could have been observing with the Nagler in 5 minutes and not risked Dave Kriege's careful measurements. I feel that I got lucky that I didn't really screw something up on this mod. Really think through whether or not you have to do this before starting. |
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