3 replies to this topic

[rwoodin3]

I recently bought a 1990's vintage Celestron C14. After getting such great help and advice on adapter issues with it, I'm posting another question.

The C14 has Starbright coatings. This is the early version of Starbright, not the later XLT.

Could anyone recommend what they think is the best coma corrector is to use on a vintage C14, either with a 1.0x or reducing optic.

Thanks in advance.

 

Ralph

[ccwemyss]

Visually, I haven't found the coma in the C14 to be bothersome. But with 14" aperture and the long FL, I tend toward objects like planets, planetaries, globulars, and smaller galaxies, rather than wide fields.

 

For large sensor photography, it's an issue (which is why they made the HD version), and you'd probably want it to be a reducer as well, to enlarge the field and shorten integration times. Starizona sells one specifically for this, and their optics get good reviews:

 

https://starizona.co...-coma-corrector

 

Chip W. 

[rwoodin3]

Visually, I haven't found the coma in the C14 to be bothersome. But with 14" aperture and the long FL, I tend toward objects like planets, planetaries, globulars, and smaller galaxies, rather than wide fields.

 

For large sensor photography, it's an issue (which is why they made the HD version), and you'd probably want it to be a reducer as well, to enlarge the field and shorten integration times. Starizona sells one specifically for this, and their optics get good reviews:

 

https://starizona.co...-coma-corrector

 

Chip W. 

Well, now that you have me sorted out on the baffle lock nut, we are mostly cloudy for the next week.

That will slow down any testing, centering, shimming and collimation that I need to do before I see how the images look at native focal length, but that's all good, I'm not in a big hurry.

Part of why I bought this C14 is to zoom in on smaller objects like you listed off.
There will be times that I'll want a wider field for nebula and medium sized galaxies.
For wider field I have a 10" f4 reflector, of course I want to keep equipment swapping to a few times a year.
I'm looking at the Starizona corrector now. Thanks for the info.

[ccwemyss]

There are a few things that don't fit well in a 41mm Panoptic, which gives the widest field available in a C14: M31 (core only, but very bright), M42 (main nebula only, without the bigger context), Pleiades, Beehive, Double Cluster (need to move a little to see all the stars), M81&82 together (but easy to move between and really see the difference in shape), probably a few I'm forgetting. 

 

But it's amazing how many "big" deep sky objects do fit. I love looking at M33, finding the spiral arms and the smaller NGCs within it. The open clusters in Auriga are rich with stars. For multiple galaxies in one view, the Virgo cluster delivers. And the smaller objects are a different experience -- globulars resolving to the core, planetaries that look solid, and building up a sense of detail on the planets by watching for those moments of seeing that reveal it, not to mention the number of moons visible around Saturn. It also delivers enough light that using filters, like an OIII on planetaries, doesn't feel like you're losing as much in brightness as is gained in contrast.

 

Chip W.