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First Light Edge 8" - .7 Reducer, Celestron OAG, ZWO EFW, ASI1600MM

astrophotography Celestron collimation dso equipment imaging SCT
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#1 NuclearRoy

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Posted 16 September 2019 - 08:08 PM

Finally got first light on the Edge HD 8". Didn't get much time on the target after reacquainting myself with collimation (the Edge was very close already) and getting all the equipment to play nice together, but I'm happy with the result for starters.

Full moon and my usual light polluted driveway left me with NB only option.

Several random locations always gave a few good guide stars for PHD2, even without rotating the OAG.

The optical train is tight with the 105mm backfocus, but it seems to be working just fine.

Attached Thumbnails

  • IC1396small.jpg

Edited by NuclearRoy, 17 September 2019 - 03:55 PM.

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#2 stargazer60

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Posted 16 September 2019 - 08:19 PM

Beautiful image, thank you for sharing the image.  Wow this is what you can achieve with the right camera and Edge HD 8".  I have a Edge HD 8" myself, can't wait to try imaging.waytogo.gif 


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#3 NuclearRoy

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Posted 16 September 2019 - 08:19 PM

Setup for the optical train is

Edge 8"

.7x Reducer

12.5mm SCT Spacer (0.5") from Agena

Celestron SCT to OAG

Celestron OAG

Celestron OAG to M42

ZWO 7x36mm EFW

ZWO ASI1600MM-Pro

ZWO290MM-Mini in the OAG (It's about half inserted with the focuser in mid position)

 

I also got the longer SCT spacer (1.5") for use without the .7x reducer. The stock one from Agena is 3mm short, so I also got a 3mm M42 spacer. We'll see if I need it or not.

 

I know several are using the thinner ZWO OAG but I liked the idea of the double rotation ability of the Celestron and the larger prism, although I guess the 290 doesn't really need it.

 

Thanks to everyone that offered advice and suggestions from their setup to get me going!! bow.gif

Attached Thumbnails

  • .7x Edge with SCT spacer and Celestron OAG.jpg

Edited by NuclearRoy, 16 September 2019 - 08:21 PM.

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#4 rkinnett

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Posted 16 September 2019 - 08:25 PM

Cool.  Looks sharp and detailed.  Thanks for the backfocus diagram, that's really helpful.

 

Is this Ha only, assigned to red channel?



#5 NuclearRoy

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Posted 16 September 2019 - 08:38 PM

Beautiful image, thank you for sharing the image.  Wow this is what you can achieve with the right camera and Edge HD 8".  I have a Edge HD 8" myself, can't wait to try imaging.waytogo.gif

Thank you Stargazer60.

I only got 90 minutes in H-alpha and at f/7.5 I don't think that is too much.

I'm used to f/4 and getting an hour or two on each filter with my Nikon lenses. This image has a lot of noise. The two stops of light loss really hurts.

 

The ZWO 1600MM is impressive. Even I can get good images with it.

 

I did notice that the plate solve was giving me ~1500mm for the focal length, vs. the expected 1400mm for the .7x reducer. Don't know what is up with that, or if using plate solve is even that accurate for determining focal length from the 'not very many significant digits', and probably not super accurate either, pixel size or chip size.

Please feel free to contact me with any imaging setup questions on the Edge. I'll be glad to pay it forward snoopy2.gif (What little I know anyway)



#6 stargazer60

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Posted 16 September 2019 - 08:42 PM

Thanks Roy for posting your hardware setup, that gives me the set up that I will get.  Clear skies.


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#7 NuclearRoy

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Posted 16 September 2019 - 08:48 PM

Cool.  Looks sharp and detailed.  Thanks for the backfocus diagram, that's really helpful.

 

Is this Ha only, assigned to red channel?

THanks rkinnett.

Yes, H-alpha only. 15x360sec. Stacked in APP. Exported as 32bit .tif to PS.

Converted to 16 bit. Levels to the edge of the histogram. 4 passes with curves.

Convert to RGB. Add red filter (656nm = 255,0,0 RGB)

Saved as .tif and run through StarNet++ to remove all the stars.

StarNet output added as top layer in PS, Blend = Normal, Opacity set to 45% (That just reduces the stars as opposed to totally eliminating them)

There, now everyone know all my secrets. lol

 

Version without StarNet++

Attached Thumbnails

  • IC1396small_no Starnet.jpg

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#8 NuclearRoy

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Posted 16 September 2019 - 08:58 PM

StarNet++ output

(I really love Nikita's program!!)

 

It generally gets all of the stars, but I guess this was a tough one. The noise probably didn't help either.

Attached Thumbnails

  • IC1396-StarNet.jpg

Edited by NuclearRoy, 16 September 2019 - 09:00 PM.

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#9 cuivienor

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Posted 17 September 2019 - 12:47 AM

I think there is one thing that's misunderstood about the back focus distance for the reducer. It is not measured from the shoulder of the reducer (as you would expect), but from the top of the threads. So you are actually too close to the reducer :)


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#10 44maurer

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Posted 17 September 2019 - 01:37 AM

I’m not sure why you are converting an Ha image to RGB. I bet it looks better before the conversion.



#11 NuclearRoy

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Posted 17 September 2019 - 08:29 AM

I think there is one thing that's misunderstood about the back focus distance for the reducer. It is not measured from the shoulder of the reducer (as you would expect), but from the top of the threads. So you are actually too close to the reducer smile.gif

Cuivienor, You are correct in that it is measured from the back of the threads, go figure.

The Agena spacer is physically longer than 12.5mm (1/2" is how they list it). Their measurement for 'length of space added' is from the shoulder inside of the female SCT threads.

Actual physical measurement of the entire optical train with a dial caliper, from the back of the reducer threads, is just a hair short of 105mm. It is hard to get it exactly because the caliper tips are not long enough to reach past all the components to the body of the reducer and still be parallel to the light path.



#12 NuclearRoy

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Posted 17 September 2019 - 08:40 AM

I’m not sure why you are converting an Ha image to RGB. I bet it looks better before the conversion.

44maurer,

Can you enlighten me on how to make the image red without converting it to RGB?

 

What really looked a lot better was the full size/resolution image before I converted it to <500k so I could upload it to the thread :)

 

Thanks,

Roy



#13 starbuckin

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Posted 17 September 2019 - 03:11 PM

What's the Agena SCT spacer? Can you post a link?



#14 NuclearRoy

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Posted 17 September 2019 - 03:59 PM

What's the Agena SCT spacer? Can you post a link?

Here you go.

From Agena Astro, it's actually a 'Blue Fireball' part. Sorry for the confusion.

https://agenaastro.c...nsion-s-sd.html

https://agenaastro.c...nsion-s-sf.html

 

For $20 the quality is not bad. Smooth threads etc.


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#15 Noobulosity

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Posted 28 September 2019 - 06:25 PM

Thanks for posting the imaging train components.  Sometimes that stuff can be challenging to figure out, with all the spacers and OAG back-focus stuff.  You certainly haven't helped me decide on my next purchase, though.  An imaging reflector (C8 Edge HD or MN190 Mak-Newt) vs a cooled camera.  Really cool image, though.

 

What's the target name/designation?


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#16 NuclearRoy

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Posted 10 October 2019 - 09:28 AM

Noobulosity, I'm with you on what to buy.

I'm liking the Edge 8. I think the 9.25 would be easier but the extra $1k can go a long way toward covering an ASI071MC-Pro or completely pay for an ASI294MC-Pro.

Decisions, decisions...

If it helps, I got the ASI1600MM-Pro and used that with my Nikon lenses for six months before adding the Edge. My thought was it would be one less thing to try to learn at the same time.

 

It's a close-up of the 'Elephant's Trunk' region of IC 1396.


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#17 Stelios

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Posted 10 October 2019 - 07:43 PM

Noobulosity, I'm with you on what to buy.

I'm liking the Edge 8. I think the 9.25 would be easier but the extra $1k can go a long way toward covering an ASI071MC-Pro or completely pay for an ASI294MC-Pro.

Decisions, decisions...

If it helps, I got the ASI1600MM-Pro and used that with my Nikon lenses for six months before adding the Edge. My thought was it would be one less thing to try to learn at the same time.

 

It's a close-up of the 'Elephant's Trunk' region of IC 1396.

The 9.25" may be doable on your CEM60, but I wouldn't want any lesser mount for it. G11 or CEM60 or premium or one of the heavyweights (EQ8, CEM120, Titan, etc.). And it would probably not track as well. The 9.25" is *much* heavier than the 8".

 

IMO, it's better to have the 8" and be overmounted. Nobody ever got hurt by that :)



#18 nofxrx

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Posted 10 October 2019 - 07:45 PM

Awesome image. 

 

I think what 44mauer is talking about is most leave the image black and white. After all, it is a mono camera.

I don't think it looks bad by any means in color, but just for a comparison why not try it in B&W? You might like it

 

Again, really awesome image, mate. You should be proud of that data. 




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