Saturday, July 25, 2009

Obsession help

Phil showed me his new toy: new Obsession Ultra-Compact Dobsonian telescope. Incredible! Very clever how it all folds up and collapses. Good workmanship.

However, he explained he was having some concerns with the collimation of the telescope as he used it. In particular, the collimation appeared to change when he moved from objects near the horizon to objects overhead. Others were reporting the problem and attributing it to the Kevlar strap suspending the mirror.

But as we started to explore, we found that the problem was elsewhere. It appears to be due to flexing in the upper cage at the focuser or in the focuser mount itself. We think this is fairly good news, actually. It suggests the primary and secondary mirrors aren't moving in relation to one another.

Phil's going to explore it some more once he gets home.

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