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#1 Adrian F

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Posted 07 December 2022 - 09:05 AM

Hello all,

I am a long time deep sky astrophotographer, first time poster here. I recently attempted to take a run at solar imaging. My setup as follows:
* Explore Scientific ED102 triplet APO. Focal length 714mm. f7
* 2” Filter (Astronomik L-3 UV-IR block)
* Daystar quark chrominance (includes 4.3 Barlow)
* QHY174mm camera
The regular back focus for this scope is 111mm for deep sky.

My question is there anyone that uses a similar setup? If so what is the backfocus being used? I have been experimenting with backfocus and have not been able to even get close to a focused image of the sun. I have gone from 80mm to 450mm in extension tubes, plus an additional 40mm draw using the focuser.

Any suggestions or assistance would be greatly appreciated.

#2 Tapio

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Posted 07 December 2022 - 09:33 AM

Does the image get better or worse if you add extensions ?

Can you provide some images what you get now using different extensions.

Anyway, I believe you can't get full disk with that focal length.



#3 Adrian F

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Posted 07 December 2022 - 09:46 AM

No real change as I add extensions.
I will try to add pictures here the next time I setup.
Yes, you are correct, full disk is not possible at that focal length.

#4 doole

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Posted 07 December 2022 - 12:25 PM

Where are you putting the extensions?



#5 LarryAlvarez

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Posted 07 December 2022 - 12:34 PM

I don't have a Quark but a lot of the images out there show it on top of a 2" diagonal.  Are you using one or just going at it straight?  Here's a link showing it 2 different ways:  Link



#6 Adrian F

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Posted 07 December 2022 - 12:37 PM

Doole-Sorry. Cannot figure out how to upload a picture on the mobile site but the order is telescope, focuser, extension tubes, in one of the extension tubes I place the energy reducing filter (as close to the quark as possible) and then quark, finally camera


Edited by Adrian F, 07 December 2022 - 01:19 PM.


#7 Adrian F

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Posted 07 December 2022 - 12:38 PM

Thank you Larry, I have tried both setups with and without the diagonal


Edited by Adrian F, 07 December 2022 - 01:19 PM.


#8 MVoltae

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Posted 07 December 2022 - 02:59 PM

A 174 based camera is a poor match for your setup and you are way over-sampling.  You need to add a 0.5x reducer to bring your focal ratio nearer to f22 to better match that camera which critically images at f22.  Also, to avoid vignetting, I suggest you purchase a 2”focal reducer.  This will require that you modify the nose of your camera as well as your quark to accept the 2” reducer.  



#9 Adrian F

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Posted 07 December 2022 - 03:11 PM

Thanks for the response, MVoltae. Is there a different camera that would work better?

I think you are suggesting that I introduce a reducer between the quark and camera? Or am I adding the reducer anyway in the image train? Not sure I have the technical skills to modify both the nose of quark and camera…will have to explore this further.

#10 MVoltae

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Posted 07 December 2022 - 05:14 PM

Although I have no experience with the QHY174M camera, like my ZWO174M, it has the advantage of a very fast FPS which is of great advantage for lucking seeing imaging. The adaptations that you may decide to make are not complicated and the components readily available from many vendors. 

Here is my setup for ZWO1744/Quark chromosphere.  The original 1.25” nose of the camera is removed and replaced with a 2” ZWO nose.  I then attach a 6mm extension, followed by a 2” 0.5X focal reducer (Antares in my case, but any inexpensive reducer will work fine).  The spacer is required to provide the correct distance between the camera sensor and the focal reducer to as to yield a 0.5X reduction. That spacing might be different in your case. I have found Agena’s Guide to Focal Reducers very helpful.    
The Quark is adapted to accept the Camera-spacer-reducer by simply unscrewing the 1.25” adapter off the top of the Quark and replacing it with a 2” Quark adapter which is available from Daystar and some vendors.  The entire unit (Camera, spacer, reducer, Quark is then inserted into the diagonal with an IR/UV blocking on the nose of the diagonal. If you decide to image straight-in by not using the diagonal, you will need to add additional spacers in front of the Quark to replace the train length of the diagonal and place the IR/UV filter someplace within your spacers. 
The important thing is to not get frustrated. Many of us on this forum have been exactly at your stage of putting together a functional system.  Keep asking questions and look forward to satisfying observing and imaging.



#11 MVoltae

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Posted 07 December 2022 - 05:19 PM

These should help

Attached Thumbnails

  • ZWO reducer.jpg
  • Quark  (1).jpg


#12 droe

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Posted 07 December 2022 - 05:29 PM

When I got my Quark, I thought I had a problem also. It is just that the quark is very difficult to focus at first. It took me awhile to get the thing focused my first time. I might have used a 50mm extension. I just added a moonlite focuser to my scope, so I am not sure I need the extension tube anymore. Definitely try to focus on the edge of the sun and make sure your Quark is warmed-up. Also try focusing with just an eyepiece (with the Quark that is), that might help. good luck - post some pics when you get them.

 

I am using:

* Explore Scientific ED 80 triplet cf APO.
* 2” Filter (Astronomik L-3 UV-IR block)
* Daystar quark chrominance
* QHY178mm camera


Edited by droe, 07 December 2022 - 05:31 PM.


#13 wxcloud

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Posted 07 December 2022 - 06:46 PM

Keep in mind at this high magnification, the focal plane is very thin, with my 80mm I find it very easy to over shoot focus racking in and out, also if you are over exposed, the sun could be pretty bloated and not have anything to focus on.

I use a straight through set up for imaging and have a 3" extension tube.
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#14 Adrian F

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Posted 07 December 2022 - 07:17 PM

Although I have no experience with the QHY174M camera, like my ZWO174M, it has the advantage of a very fast FPS which is of great advantage for lucking seeing imaging. The adaptations that you may decide to make are not complicated and the components readily available from many vendors. 

Here is my setup for ZWO1744/Quark chromosphere.  The original 1.25” nose of the camera is removed and replaced with a 2” ZWO nose.  I then attach a 6mm extension, followed by a 2” 0.5X focal reducer (Antares in my case, but any inexpensive reducer will work fine).  The spacer is required to provide the correct distance between the camera sensor and the focal reducer to as to yield a 0.5X reduction. That spacing might be different in your case. I have found Agena’s Guide to Focal Reducers very helpful.    
The Quark is adapted to accept the Camera-spacer-reducer by simply unscrewing the 1.25” adapter off the top of the Quark and replacing it with a 2” Quark adapter which is available from Daystar and some vendors.  The entire unit (Camera, spacer, reducer, Quark is then inserted into the diagonal with an IR/UV blocking on the nose of the diagonal. If you decide to image straight-in by not using the diagonal, you will need to add additional spacers in front of the Quark to replace the train length of the diagonal and place the IR/UV filter someplace within your spacers. 
The important thing is to not get frustrated. Many of us on this forum have been exactly at your stage of putting together a functional system.  Keep asking questions and look forward to satisfying observing and imaging.

ThNk you for this information, I will look into a focal reducer.  Appreciate the advice



#15 Adrian F

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Posted 07 December 2022 - 07:24 PM

When I got my Quark, I thought I had a problem also. It is just that the quark is very difficult to focus at first. It took me awhile to get the thing focused my first time. I might have used a 50mm extension. I just added a moonlite focuser to my scope, so I am not sure I need the extension tube anymore. Definitely try to focus on the edge of the sun and make sure your Quark is warmed-up. Also try focusing with just an eyepiece (with the Quark that is), that might help. good luck - post some pics when you get them.

 

I am using:

* Explore Scientific ED 80 triplet cf APO.
* 2” Filter (Astronomik L-3 UV-IR block)
* Daystar quark chrominance
* QHY178mm camera

Thanks for these words of advice.  I have been trying to focus by hand but think I may have not been able to get to the fine adjustments.  I have a focuscube on another scope for deepsky.  I may will switch it over to this rig and run through focus runs again starting at one extension and going through the different back focus extensions.  It would make sense if I blew through the narrow focus point at this magnification.  
 

Once I achieve focus with the eyepiece do I simply replace with the camera and I do not have to re-focus?



#16 Adrian F

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Posted 07 December 2022 - 07:30 PM

Keep in mind at this high magnification, the focal plane is very thin, with my 80mm I find it very easy to over shoot focus racking in and out, also if you are over exposed, the sun could be pretty bloated and not have anything to focus on.

I use a straight through set up for imaging and have a 3" extension tube.

I think I will transfer my focuscube onto this scope and restart from scratch.  I suspect my challenge has been hand focusing and not being able to gain fine enough adjustments.

 

with image settings, I have been between 4ms to 20ms for exposure length, and then adjusting gain to no bloat/white out the sun itself.  Does that sound like I am on track?  Or am I over/under exposing?



#17 mogur

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Posted 10 December 2022 - 07:33 PM

The OP states that a 102mm scope is being used. Quark recommends the use of a FRONT mounted ERF on any scope over 80mm. What would be the effect of having two ERF's in the optical train, other than a slight dimming of the view?


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#18 hopskipson

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Posted 11 December 2022 - 05:45 PM

The OP states that a 102mm scope is being used. Quark recommends the use of a FRONT mounted ERF on any scope over 80mm. What would be the effect of having two ERF's in the optical train, other than a slight dimming of the view?


Daystar recommends a ERF in front of the Quark for telescopes 80-150 mm and an objective mounted ERF for greater than 150 mm. So a UV/IR blocking in front of the Quark is all that is needed for a 102mm scope. I would recommend a Baader red imaging filter for this.

#19 wxcloud

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Posted 12 December 2022 - 12:46 AM

I think I will transfer my focuscube onto this scope and restart from scratch. I suspect my challenge has been hand focusing and not being able to gain fine enough adjustments.

with image settings, I have been between 4ms to 20ms for exposure length, and then adjusting gain to no bloat/white out the sun itself. Does that sound like I am on track? Or am I over/under exposing?


Exposure time is something you'll have to experiment with along with gain. First order of business is to actually locate the disc of the sun which can be a challenge. Once located, use the edge of the disc to try and focus, to get a sharp edge, it might be a little weird depending on how magnified your view is, how your exposure is and so on. One thing to note if you're magnified enough you might actually see both the edge of the sun (limb) and then a fuzzy outer part which are spicules.

It's been a while since I've imaged and can't quite remember the settings on my 174... Perhaps a gain of 101 (could be wrong) and 5ms exposure through fire capture. You can adjust to taste.

Hope this is helpful :)

#20 Adrian F

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Posted 12 December 2022 - 11:11 PM

Exposure time is something you'll have to experiment with along with gain. First order of business is to actually locate the disc of the sun which can be a challenge. Once located, use the edge of the disc to try and focus, to get a sharp edge, it might be a little weird depending on how magnified your view is, how your exposure is and so on. One thing to note if you're magnified enough you might actually see both the edge of the sun (limb) and then a fuzzy outer part which are spicules.

It's been a while since I've imaged and can't quite remember the settings on my 174... Perhaps a gain of 101 (could be wrong) and 5ms exposure through fire capture. You can adjust to taste.

Hope this is helpful smile.gif

Thanks for the tips.  Just waiting for clear sky’s…haha



#21 Adrian F

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Posted 12 December 2022 - 11:15 PM

The OP states that a 102mm scope is being used. Quark recommends the use of a FRONT mounted ERF on any scope over 80mm. What would be the effect of having two ERF's in the optical train, other than a slight dimming of the view?

 

Daystar recommends a ERF in front of the Quark for telescopes 80-150 mm and an objective mounted ERF for greater than 150 mm. So a UV/IR blocking in front of the Quark is all that is needed for a 102mm scope. I would recommend a Baader red imaging filter for this.

Sorry about the delay in responding.  I only have one filter in front of the quark (Astronomik L-3 UV-IR block).  And just received confirmation from Daystar that I do not need a filter in front of the scope at this aperture.


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#22 mogur

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Posted 13 December 2022 - 12:43 PM

Sorry. I guess I misread the copy sent with the Quark unit. Still wondering what effect having two ERF's in the optical train is for anyone who has tried it. When I use one in my 72mm it seems to actually improve the view, even though it's not really needed at that aperture. The Quark has filter threads on the front of the unit so that's where I put the UV/IR cut filter. My setup has the Quark in front of the diagonal in this case. In my other two scopes I can use a 2" diagonal so it would be possible to have one on the front of that plus one on the Quark. I guess I should just try it and see what effect it has, if any, instead of asking stupid questions.



#23 Adrian F

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Posted 14 December 2022 - 06:22 PM

Well I just wanted to thank everyone for the help tips and advice.  I was able to get a "focused" view of the sun today.  Obviously, seeing was an issue as the sun was setting behind a roof when we were finally able to see the edge.  Back focus was the issue for sure.  For anyone else who has a ES ED102 triplet, I needed to use the following extensions

  • 3.5 inch (or 90 mm) extension tube
  • 3 inch (80 mm) extension tube

The ERF was placed as close to the quark as possible (end of 80mm extension tube).

 

The focuser was racked out to approximately 27-28mm.

 

I can not say enough about David of David's astro online store.  He sold me the ES scope and turns out he is a solar imager too.  He and I were able to get onto a zoom call and he was able to assist with the challenges I was experiencing.  He confirmed that I was close to the sun, showed me how to work the settings in sharpcap to start to dial in the focus.  He spent alot of time with me trying different backfocus ranges until we finally saw the edge.  What amazed me was he was willing to take the time to assist me, even though he only sold me the scope (the quark was purchased elsewhere).


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#24 Tapio

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Posted 14 December 2022 - 09:39 PM

Quite long extension you needed but glad you got it sorted.
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