BORG M75 Helical Focuser & 1.08x Flattener

M75 helical focuser is a very fine pitch focuser. Finest among BORG focuser family. But my “excuse” out-of-focus problem last weekend was that the focuser was too far to reach while viewing camera’s rear screen. The focuser was set behind the objective, a flattener moves a camera back and a cooled camera’s screen is further back. All 3 factors gave me struggling.  Actually very hard to see LCD screen while reaching to the focuser. So I re-set the focuser at rear side as follows

0504cNow It looks better. Still further than normal though. Anyway, much more comfortable now. My fundamental problem is my eyes are getting older and more astigmatism though. Next time, I will try to use SS-one Complete, which allows to focus on its controller. So I don’t have to hassle to view camera screen.

BTW, I wanted to mention the focuser’s secret functions.

  1. Both ends’ threaded rings are removable, which gives the freedom of focuser’s attachment. You may decide the direction based on your favorite. 0504a2. 2nd is it has a taper ring inside which was originally intended to adjust the focuser’s orientation. Same time, it works as camera rotator too. I added 5 thumbscrews. It’s M4. You can replace by yourself. But probably the curved smooth tip should be more suitable. I have a lot of such thumbscrews. It’s a bit too long though. If you specify the request in future shipment, I’m happy to enclose them to your box. New 107FL reducer which is expected to release this fall will be large size. So the focuser’s camera rotator should be default like this. Maybe BORG will provide thumbscrews as option that time.

About 7108 with 107FL, the flattener has no 600mm index mark. So set a lens barrel as shown below.

0504bThe optical distance for 7108 is not super sensitive. So you don’t have to be too careful.

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~ by tedishikawa on May 4, 2017.

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