Quote:
Originally Posted by mbaddah
I have the Orion Chessire Sightube purchased from Bintel ($70). I sometimes find it bit difficult to look through due to the small peephole and cross in centre, or is that just me  |
The hole is fine for me but the crosshairs drive me crazy - never in focus for me. But crosshairs are there for a good reason - for final alignment. But you can use them as a guide on the secondary mirror position. But I suggest that you ignore them and concentrate initially on the edge of the secondary mirror. Perhaps put a piece of white paper on the opposite wall of the OTA so the mirror and mirror holder stand out distinctly. Objective is to get that secondary nicely centred in the view you have of the end of the sight tube, and looking completely round. Relevant adjustments are the central screw, the three collimating screws (though they are primarily for another purpose) and the nuts positioning the spider (hopefully the spider is well centred from the factory, but you never know.)