Celestron C6 SCT

[MortonH]

I'm looking for a good C6 OTA for a bit more aperture than my excellent C5.

I've seen some SCT's that have an annoying flaring effect when a bright object is just outside the FOV. Obviously I want a scope that doesn't suffer from this (or the effect is minimal).

Please PM me if you have one to sell.

Note: If anyone is interested in my C5 I will probably sell it once I find a good C6. It's a black tube model with Starbright coatings. I believe it was originally sold with a mount as the G5 in the '90s. Optically it's very good and condition is excellent.

[MortonH]

Still looking. May consider a trade for my C5 plus cash if anyone is interested.

[linkpng]

Hi Morton and other star diagonal users,
About the 'flare' problem: as an old lunar occultation observer I found the same problem with other scopes where a star diagonal is used. The flares may not be caused by your main SCT optics; your C6 may be better than you think. Note that if an object is just outside the field of view of an eyepiece, it can still be within the field of view of the telescope. Then consider the light path through the diagonal.

By viewing the optics - with the eyepiece removed - I found that in many cases the 'flares' were reflections off the tube and sides of the diagonal. Solved this by adding a simple baffle just ahead of the diagonal as described in this technical note:
https://tufi2.files.wordpress.com/2018/03/contrast-improvement-by-baffling.pdf
That example is specifically aimed at occultation observers. Of course most observers do not need such a severe restriction but the same principle applies. Do some light tracing and experiment with different baffle apertures.
Hope this helps, Alfred

[MortonH]

Thanks Alfred. There are also plenty of cases on Cloudy Nights of SCT's & Maks with an inadequately painted/blackened baffle tube that can cause these arcs. Seems to be more of a problem with the ones made by Synta but it doesn't affect all of them (I previously owned a C6 that had no problem). Just trying to make sure I get a good one. :)

[MortonH]

Still looking for a good C6.

PM if interested in selling.

[MortonH]

Would love to find one before the nights start getting short!

[AusS2000]

My Evolution 6 will be available for sale soon. Just the OTA as I've upgraded mine but it should work well with your existing mount.