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Old 24-06-2005, 02:52 PM
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asimov (John)
Planet photographer

asimov is offline
 
Join Date: May 2005
Location: Bundaberg
Posts: 8,819
Question Mods to el-cheapo 4.5" reflector

Hi guys.

I'm in process of doing a few mods to a little reflector I inherited off my dad years ago. I replaced the .965" focuser with a 1.25". After fitting it, I pretty well knew I wouldn't be able to come to focus because of the extra height of the new focuser. I needed the primary closer to the EP 25mm.

I very nearly just cut an inch off the primary end of the tube, but decided to move focuser/diag/finder towards the primary instead. {I couldn't just move the primary up the tube cos' the cell is built into the tube reinforcement ring}

After I did all that, I collimated, took it out for a test. The trouble I'm having is kinda hard to explain. When I de-focus heavily, {outside of focus} on a star, It looks like I'm not receiving the full light from the primary, I see like a cresent....like a 3/4 full moon.

It's probably crappy collimation causing it, but I'm just wondering if it was the right thing to do by adding the bigger diameter focuser without adding a slightly bigger diagonal mirror?....The diagonal I'm using is 25mm diameter.

TY in advance.
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