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Starizona SCT Corrector

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44 replies to this topic

#1 tomo

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Posted 04 May 2011 - 01:30 PM

Has anyone got first light comments on this?
http://starizona.com...r-P3230C91.aspx
I'd really like to see an actual comparison with a generic f/6.3.

Clear skies,
Tommy

#2 tomo

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Posted 04 May 2011 - 01:31 PM

btw, it would be a great way to turn my c-11 into an edgehd-11. Does anyone know of competitive products?

#3 Zoeff

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Posted 04 May 2011 - 02:30 PM

That looks quite interesting. I'd also like to know if anyone here on CN has tried one of these...

#4 tomo

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Posted 04 May 2011 - 03:46 PM

What about this?
http://www.astrosyst...segrain-Red.pdf

#5 bill w

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Posted 04 May 2011 - 11:42 PM

both look very cool, great idea
wish i'd seen these before i bought the LX200R.
interestingly, they look like starizona's answer to the edge
which is not hyperstar compatible.
hope there's not too much conflict there

#6 tomo

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Posted 05 May 2011 - 08:51 AM

If they can do what they say they can then I expect Starizona would commission a study to quantify the advantage (scientifically speaking). Just putting a couple of shots on the website doesn't really mean much I'm afraid. If they did this it would help close the deal for me.

#7 Alph

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Posted 05 May 2011 - 04:41 PM

If they can do what they say they can then I expect Starizona would commission a study to quantify the advantage


Did Celestron commission a study on the HD series?

#8 Richard Scott

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Posted 05 May 2011 - 05:40 PM

This Starizona Corrector/Flattener seems like exactly what I have been looking for. Coma has always been an issue with my C11 and ST8300. I would love to hear from someone about how it performs, but It has gone way up on my "Gota have" list sight unseen.
Richard

#9 tomo

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Posted 06 May 2011 - 08:15 AM

Hi Alph,
When companies (Starizona, Celestron or whoever) make these products they should do internal concept design followed by testing that is based on specs that show it hitting the perceived market need. If they do it right this can be translated into a nice marketing piece.
Tommy

#10 tomo

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Posted 21 May 2011 - 06:22 AM

Just thought I'd raise this question again. Has anyone used one and would like to report back? Perhaps I should then?

#11 Zoeff

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Posted 21 May 2011 - 09:12 AM

Just thought I'd raise this question again. Has anyone used one and would like to report back? Perhaps I should then?


From the looks of it nobody dares to buy an unproven product, which is unfortunate. :(
I don't have any use for one right now but I'm still curious to see how it performs when a customer uses one, I'd definitely read your review of it. :)

#12 PiotrM

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Posted 21 May 2011 - 11:24 AM

There is a lot (?) of reducers/correctors for SCTs. It looks like the slower the reduction is the better field they can give. Check for example also TS 0.8x reducer/corrector. There is also ~f/5.9 Baader Alan Gee II and optec from 0,33 to 0,77. Every one of them has some limitations, and max field it can support.
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#13 BlueGrass

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Posted 10 October 2011 - 09:00 PM

Bumping this thread since it's been dormant for 5 months.... I've been looking at this corrector on and off for the past month, trying to decide if $400 would be a good investment to improve my C8's images.

I may have to be the first? ... :shrug:

#14 PatHolland

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Posted 10 October 2011 - 11:02 PM

Hey George, I have the corrector but have not used it yet. I'll have to get back to you when I get a chance to try it out.

#15 BlueGrass

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Posted 11 October 2011 - 09:11 PM

Pat,
That's great and thanks. I'm sure there are a number of folks who've been looking at this corrector / reducer to improve their SCT's imaging performance. The promise of reduced coma and a flatter image... is very enticing to say the least.... look forward to your report. I see you've got an ACF and the other two are HyperStar setups. Are you planning on putting the standard secondary back in the C8 and using that?

#16 Charles Wright

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Posted 18 January 2012 - 09:06 AM

Add another person to the list of the interested.

Charles

#17 PiotrM

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Posted 18 January 2012 - 09:22 AM

check this out too: http://stargazerslou...ector-test.html

#18 PatHolland

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Posted 18 January 2012 - 10:10 AM

Sorry George, I missed your post. Yes, I am planning on using this on the C8 pretty soon (galaxy season). I will write a full review of the FF/FR when I get a few images with the Canon (26mm) and the H-18 (22mm). I have not been able to get under the stars much in the last year or so be it work or weather related. I know a lot of people are waiting for a review before they make a decision to purchase. Getting the Starizona FR/FF up and running is becoming a top priority for me.

#19 sullij1

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Posted 18 January 2012 - 04:39 PM

check this out too: http://stargazerslou...ector-test.html


Thanks, Very valuable information at this link. Added to favorite threads. Focal reducers cause much ruckus within the SCT world. The test and backfocus data helped.

#20 bigol

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Posted 20 September 2012 - 04:50 AM

Hello!
I have Celestrone C-11 telescope.
In spring 2012 my sister purchased Starizona SCT Corrector (SCTCORR75) for me. At the moment of the order I was unsure which camera I shall use, so we ordered just the corrector. Eventually I started using it with Canon 1000D and the adapter was prepared following the recommendations on the website. Precisely following the instructions, the length of the adapter plus T-ring is 46,3 mm. It is shown in the picture. According to the site's info, the correction of aberations is supposed to be excellent, taking into consideration that the size of the camera matrix is only 26,7 mm, while the corrected field of your corrector is 36 mm. However, during the process I faced strong coma in the corners of an image, as you can see it in all the corners in the foto. In my opinion, that result cannot be judged as the "corrected field". I'm asking you for your advice and help in the finding the cause and the solution for improving the results of the corrector's performance. I wrote this mail to starizona but didn't recieved any answer :(

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  • 5430379-corners_2.jpg


#21 bigol

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Posted 20 September 2012 - 04:53 AM

And adapter's foto

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  • 5430381-sct_2.jpg


#22 freestar8n

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Posted 20 September 2012 - 04:56 AM

I would try changing the spacing from the reducer to the imaging chip. If you measure the image scale in arc-sec per pixel - does it match the intended reduction factor? If the value you get shows the reduction is too much (the image is too small) you should move the camera toward the reducer, and if too big move it away.

The reducer itself should be attached directly to the back of the sct.

I haven't used that reducer, but I would expect it to be similar in this way to the 0.63x reducer.

Frank

#23 freestar8n

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Posted 20 September 2012 - 05:05 AM

From your picture it looks like it would be close to the intended 90mm backfocus - if the camera backfocus is around 42mm. Are you attaching the reducer directly to the back of the sct? It should be - and not attached to an external focuser, for example.

It seems like if it is attached directly to the sct back and the spacing is about 90mm and the image scale shows 0.75 reduction - there might be a problem. Maybe one or more of the lenses inside is backwards.

Frank

#24 bigol

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Posted 20 September 2012 - 05:45 AM

Hello, freestar8n and thank you for ansrwer.
Canon EF(-S) bayonet is exactly 44mm. So, it is 44mm+46.3=90.3mm - as need according starizona.com
I measured my images scale in arc-sec per pixel by pinpoint astrometry - it says smth. about 2020-2040mm. Concerning reduction factor - it depends from position corrector in sct-outback. It may be more or less deeper, because corrector hasn't any mechanical restrictions for place it in sct-outback or sct-focuser. In technical characteristics also there are no requirements about its arrangement in a telescope. We only need right backfocus - 90.3mm from edge of t-thread to matrix.

#25 freestar8n

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Posted 20 September 2012 - 06:08 AM

Hi-

I agree the main thing is to have the distance from the corrector to the image plane as near 90mm as possible, but at the same time there will be some degredation if you move the corrector away from the back of the sct. The manual for the corrector says:

"Ideally, the SCT Corrector will be mounted as close to the back of the telescope as
possible. The performance of the lens does not change significantly if the SCT Corrector is
farther from the telescope, but the focal reduction factor changes, reducing the field of view and increasing the telescope's focal ratio."

Since your f/ratio appears to be 7.25, it seems close to the intended 7.5 and something seems wrong. This *is* a normal c11 - and not EdgeHD - correct? It is not expected to work with EdgeHD.

If you can confirm that it gives nearly the same results when the corrector is attached directly to the back of the sct, then it looks like something is wrong, and one possible cause would be to have a lens inside mounted backwards.

Frank


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