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First Light with my new William Optics ZenithStar 71mm ED


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So, this is the product of my first light with my William Optics ZenithStar 71 APO Doublet from Tues night (I didn't get this done till today due to work yesterday, etc). 


William Optics ZenithStar 71mm APO Doublet (418mm)

Sony a6000 camera

Celestron AVX mount

Unguided, but tracked (part of my guidance came in...unfortunately, it's not the camera part...it'll be here next week)

45 x 30 sec exposures, ISO 640

I think that this scope takes very nice, crisp images. The only issue I have with it is that there's some chromatic aberration around the bright stars that I haven't been able to solve with either PixInsight or Photoshop. I'm not sure if it was my exposure, my ISO, or what. the actual focus was dead on, and I can provide the Bahtinov mask image to prove it!

Anyone have any suggestions? Thoughts? Comments?




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I have not seen the exact effect that you describe but suspect it could be as a result of processing and would be interested if the halo`s where as pronounced on your subs.

I have found that focus with my own scope is rather critical and a bat mask gets you a result that leaves the blue channel a little bit off and so I prefer to use liveview x10 on the faintest object in the FOV but thats me.


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I'd be delighted with an image as good as that and I aspire to replicate it as I'm new to AP.

I was lucky as Santa brought me a 130mm triplet for Xmas with a focal reducer so now f5.7. Hopefully I'll manage to produce something as good as yours.

Is a Sony a6000 a DSLR?

I have a unmodified EOS550 and a ZWO ASI120MC - which would be best to produce a similar image and how would I do it?

ps  - I don't have any imaging software at the moment

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They are like that in the subs and I wonder if the focus is tooooo focused with the mask

I know what you mean I have come to the same conclusion that perfect focus isnt the same as best focus with any 2 element design, you could split the channels into RGB with photoshop and have a peek to see which one is causing the biggest problem.

The image itself though is a very good 1st attempt and shows a lot of potential.


Edited by Alien 13
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So, after spending some time this evening with photoshop and on the phone with my good friend Bradley Kalpin, we came up with a way to correct the aberrations that were in the previous version of this. I used the healing tool in Photoshop to repair the aberrations, which then allowed me to resaturate the shot and get the right color balance back so that it wasn't so pale and anemic looking.

I just wish I had some more time to spend with the scope outside so I can see if I can do something with in-camera tricks or whatnot to avoid the aberrations in the future. I love how sharp the scope is, all the way down through the shot. I can live with the aberrations if that's what I'll be left with because I really think it's a sharp instrument to work with!

Let me know what you think of this version over the other!




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