celestron c5

I obtained a used celestron c5. It has a loose corrector plate. Is there a given protocol for correctly centering the plate (say, some home-built spacers at the perimeter) or must this be sent to celestron. Is believe I read about this being a somewhat common problem with a certain generation of c5's.

Also, the focus knob on this C5 moves VERY freely. It moves the mirror and focusing works fine, but I was surprised at the ease of movement. Is this normal?

Thanks for any insights,

David B

David Bacheller said:

I obtained a used celestron c5. It has a loose corrector plate. Is there a given protocol for correctly centering the plate (say, some home-built spacers at the perimeter) or must this be sent to celestron. Is believe I read about this being a somewhat common problem with a certain generation of c5's.

Also, the focus knob on this C5 moves VERY freely. It moves the mirror and focusing works fine, but I was surprised at the ease of movement. Is this normal?

Thanks for any insights,

David B

HI:

Older Celestrons had considerably easier focus action than the old ones. The way to center a corrector is via little paper shims. Were there none in place?

A newbie follow-up for my C5:

I removed the retaining ring and the corrector plate. I tried to fabricate paper shims for the perimeter but found no satisfaction there, so I used some appropriate diameter rubber O rings. These 0 ring sections (about 1 cm in length) were placed at four positions at the perimeter of the corrector plate. The retaining ring was then installed.


I found the use of cotton surgical glove liners to be nice hand covers for handling the corrector and, in fact, performing all of the above. I viewed Jupiter last night with the reconstituted scope and so far so good. Must get a new battery for the dot finder.

David B