Vixen telescope repair

Hi all,
About a year ago, I purchased a Vixen VMC110L Maksutov-Cassegrain OTA, to move up a small notch from my Skylux.

I have since managed to knock a big chip off the edge of the primary mirror (it's too embarrassing to tell the rest of the story... )and I'm having great difficulty finding either a replacement mirror or a repair shop. Does anybody here know any vixen dealers/repairers. I've also emailed the Vixen website, but have received no reply yet.

Or would any other Mak mirror of the same size do the job?

Thanks in advance.

Stephen

Hi Stephen, I don't know myself, but is the lump large or small? if it does not affect your observing that much would you be happy to leave it like that?

Also orionoptics in the uk are vixen dealers, maybe you could give them a bell.

www.orionoptics.co.uk/VIXEN/vixentelescopes.html

Best of luck,

Keith..

Hi Stephen,

Commiserations! As Keith has already said, unless the chip is actually affecting the image you are as well to leave it be, and just black out the chip with some matt black paint to cut down light scatter. The quickest way to evaluate the effect of the chip is to do a star test - point your scope at a bright star and centre it in the field of view. Then examine the slightly defocussed diffraction pattern using a high-power eyepiece. If the image is generally round, then you've been lucky and the chip hasn't released any internal stresses. If the image is clearly non-circular at the orientation of the chip (stick your finger or hand into the light path and move it around the circumfrence of the aperture until it lines up with the chip) then you might look for a replacement mirror.

The primary mirror in a Mac-Cas is spherical, and so relatively cheap to manufacture. The original manufacturer should be able to provide a replacement optic at a reasonable price. Replacing it with an optic from another source could be a problem if the mirror is tapered out towards the edge as in most SCTs.

Phil.

Thanks for the valuable feedback. I have attached a diagram showing the approximate size and position of the chip.
I think for the moment I will black out the chip as recommended, re-collimate and see how I go from there.
The next hurdle will be collimating it

Thanks again

Pic should work this time

How did you do it?