Telescope Reviews: Re: Objective lock-ring collimation

The correct tool for this job is pictured...a spanner wrench. I got mine from Edmund Optics. It comes with three tip pairs and two spanner bars, the long one will span 7 inches. I have found it an invaluable tool for working on my refractors.

As far as binoculars, my BT100 has an eccentric lens cell that could be rotated to correct for a centering misalignment, but I have never attempted this. I loosened the outer retaining ring that was overtightened to correct some astigmatism apparent in the left barrel at high power...43x.

BTW, I corrected for conditional collimation by using a illuminated reticle eyepiece, focusing and centering the crosshairs on a distant light in the valley below (6 miles away) and switching back and forth between barrels adjusting the non dominate eye barrel (in my case the left) against the dominate barrel, using the prism adjustments. This is quite precise and easy to do.

Checking against star images with one barrel defocused and the other focused shows the star superimposed and centered on the extrafocal image. This is IMO a good "quick and dirty" check for collimation and is more precise than Oberwerk's collimation procedure.

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10x50 Fujinon FMT-SX binos
15x70 AP binos + Paragon p-mount
Oberwerk 100BT 45 degree + Hercules fork mount
120mm f/5 Orion achromat + Moonlite focuser
140mm f/5.7 Vixen NeoAchro Petzvel refractor
150mm f/6.5 Antares achromat
150mm f/8 homemade achromat....EE Barnard MW Sweeper
8 inch newt with f/5 Swayze mirror
10 inch f/4.7 Orion newt + Paracorr
15 inch f/5 Discovery split tube
35mm Pan, 26mm Nagler, 17mm Nagler, 13mm Ethos, 8mm Ethos

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Edited by Mr. Bill (05/28/08 05:33 PM)

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