Full disk scope for Quark?

this is the main message area for anything solar :)
Post Reply
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Full disk scope for Quark?

Post by minhlead »

I am using a Quark Chromosphere for imaging with a QHY294C (a color camera with M4/3 sensor).
I have 2 scopes: the FRA400 (400mm focallength) and the sharpstar 107ph (700mm focal length)
The thing is even with the FRA400, I still cannot fit the full disk into my sensor although the sensor already cover the whole pupil exits of the Quark with plenty of black border.
I tried an old lens with 200mm focal length and the result was bad. The disk fits nicely but it lacks sharpness (the contrast was okay) and have huge halo on 1 side of the disk (pictured below, stretched to better show the halo) (I use an old manual SMC M42 Takumar 200 F/4 Stopped down to F/7 with the internal aperture)
Screenshot_20210729-215856_TeamViewer.jpg
Screenshot_20210729-215856_TeamViewer.jpg (233.15 KiB) Viewed 568 times
My questions are:
1. What are the source of the halo pictured above? Is it some kind of reflection inside the lens? I use this Quark with my 107 and FRA 400 and see some degree of halo but none close to that bad. Is it possible the halo/reflection comes from the internal aperture of the lens? Would it go away if I use an front aperture mask?
2. Why the lens seems to lack sharpness when use with the Quark? The lens is quite sharp when I use it for DSO/every day imaging.
3. What scope do you use for full disk with your Quark without having to do mosaic? I think a 200mm or so scope /lens with F6-F7 would do fine.
Thanks


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

Here's an image of my setup. With the problem described above.
20210727_104205.jpg
20210727_104205.jpg (3.07 MiB) Viewed 567 times


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
User avatar
cmas
Ohhhhhh My!
Ohhhhhh My!
Posts: 144
Joined: Sat May 06, 2017 5:49 pm
Has thanked: 294 times
Been thanked: 248 times

Re: Full disk scope for Quark?

Post by cmas »

Hey,

A comment on a full disk setup with Quark: I use Sharpstar 61 EDPHii. With that OTA and Quark I can reach a full disk in one shot (no mosaics) with ASI174mm using Daystar reducer and some T2 extensions between the reducer and the sensor. You can look my Flickr for the imaging setup photos and if needed I can take new photos too as I'm currently using a quark-to-t2 adapter, the t2-to-m48, the reducer and some t2 extensions before the camera (earlier I was using a 2" adapter for the Quark and putting the reducer inside it etc). This little Sharpstar has a nice focuser and solid mechanics and this is the reason I'm using it instead of some cheaper achro.

I would like to use e.g. my 80 mm f/6 apo scope for full disk but can't really see it happening easily. The Quark really has not been designed for full disk imaging. Maybe the combo version would be better in this sense, but you'd have to use less magnification which would bite you in the leg when it comes to contrast etc.


H-alpha: Baader D-ERF, Sharpstar 61 EDPH II, Altair Astro 102 f/7, Quark, reducer and ASI174mm.
White light: Baader ASSF 115, Sony SEL 200600G, Sony SEL20TC, Sony A7iii.
Images in AstroBin
Images in Flickr
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

cmas wrote: Thu Jul 29, 2021 3:24 pm Hey,

A comment on a full disk setup with Quark: I use Sharpstar 61 EDPHii. With that OTA and Quark I can reach a full disk in one shot (no mosaics) with ASI174mm using Daystar reducer and some T2 extensions between the reducer and the sensor. You can look my Flickr for the imaging setup photos and if needed I can take new photos too as I'm currently using a quark-to-t2 adapter, the t2-to-m48, the reducer and some t2 extensions before the camera (earlier I was using a 2" adapter for the Quark and putting the reducer inside it etc). This little Sharpstar has a nice focuser and solid mechanics and this is the reason I'm using it instead of some cheaper achro.

I would like to use e.g. my 80 mm f/6 apo scope for full disk but can't really see it happening easily. The Quark really has not been designed for full disk imaging. Maybe the combo version would be better in this sense, but you'd have to use less magnification which would bite you in the leg when it comes to contrast etc.
I can see the focal reducer option too but it's quite expensive and I heard the sharpness is not that good. Looking for a cheaper option. May be a cheaper reducer?
Did you ran into the sharpness problem with the DS Reducer?


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
User avatar
cmas
Ohhhhhh My!
Ohhhhhh My!
Posts: 144
Joined: Sat May 06, 2017 5:49 pm
Has thanked: 294 times
Been thanked: 248 times

Re: Full disk scope for Quark?

Post by cmas »

I haven't got sharpness issues with my reducer. Or at least you can check my images and decide yourself.

Some do use cheap reducers, though, so there's always that option. But they may or may not be working, cannot comment anything on that. When I bought my reducer I found that many had issues with cheap reducers and decided to get the daystar version. But as I said, full disk with Quark leads to compromises always with the FOV and uniformity etc. For it's price it's a really nice component (the Quark that is), but no means perfect nor optimal.

If I'd pack a lot of cash, my full disk setup would most likely be 60 mm or preferably 80 mm DS Lunt or similar. But I'm still waiting to win in lottery ;)


H-alpha: Baader D-ERF, Sharpstar 61 EDPH II, Altair Astro 102 f/7, Quark, reducer and ASI174mm.
White light: Baader ASSF 115, Sony SEL 200600G, Sony SEL20TC, Sony A7iii.
Images in AstroBin
Images in Flickr
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

cmas wrote: Thu Jul 29, 2021 3:54 pm I haven't got sharpness issues with my reducer. Or at least you can check my images and decide yourself.

Some do use cheap reducers, though, so there's always that option. But they may or may not be working, cannot comment anything on that. When I bought my reducer I found that many had issues with cheap reducers and decided to get the daystar version. But as I said, full disk with Quark leads to compromises always with the FOV and uniformity etc. For it's price it's a really nice component (the Quark that is), but no means perfect nor optimal.

If I'd pack a lot of cash, my full disk setup would most likely be 60 mm or preferably 80 mm DS Lunt or similar. But I'm still waiting to win in lottery ;)
Yep. How about flatfield correction? How do you make a flatfield for full disk? I use a diffuser similiar to Daystar flat cap but while it worked very well for close up, it does not seems to work well with full disk, the dust spots still there. Am I missing something here because on DS's flatcap introduction video they said the diffuser method works for fulldisk


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
User avatar
cmas
Ohhhhhh My!
Ohhhhhh My!
Posts: 144
Joined: Sat May 06, 2017 5:49 pm
Has thanked: 294 times
Been thanked: 248 times

Re: Full disk scope for Quark?

Post by cmas »

All my full disk H-alpha images and animations taken during 2021 are without any flatfield correction. You can see some uniformity and flat field related issues e.g. in my animations. So take a look at them and you'll see what level issues I have.

I tested recording flats via unfocusing (which works nicely with higher magnification) but the tracking in my SolarQuest is not good enough for full disk flats so I just don't take them.


H-alpha: Baader D-ERF, Sharpstar 61 EDPH II, Altair Astro 102 f/7, Quark, reducer and ASI174mm.
White light: Baader ASSF 115, Sony SEL 200600G, Sony SEL20TC, Sony A7iii.
Images in AstroBin
Images in Flickr
RodAstro
Im an EXPERT!
Im an EXPERT!
Posts: 385
Joined: Sun Oct 29, 2017 9:51 pm
Has thanked: 286 times
Been thanked: 399 times

Re: Full disk scope for Quark?

Post by RodAstro »

Hi Minh

A 50 mm finder/guider works well.
You can put a reducer before the Quark I do this on my 150mm f15 refractor to bring the image scale down, not for full disk, but it would work on a smaller scope.
I use a Pixco 0.7 camera reducer taken out of the camera fitting and then fitted into a 58mm extension tube to adapt it to my quark front, the beauty of this reducer is, it does not alter the focus point and it is all air spaced so no heat problems.
You could fit one to the back of a camera lens.
I have been using a 50mm finder with a 0.5 cheapo reducer onto an ASI174mm after the quark for full disk it seems to work ok, remember its monochromatic light so you don't need any fancy corrected reducer.
I would recon your reflection will come from the lens, probably not to many coatings inside. have you stopped it down to get a higher f ratio?
On my Solar Scout SS60-DS I have to stop it down to 30mm to get anything like a good image and when you work it out that's about F32 at the etalon so near the Quarks optimum.

Cheers Rod


RodAstro
Im an EXPERT!
Im an EXPERT!
Posts: 385
Joined: Sun Oct 29, 2017 9:51 pm
Has thanked: 286 times
Been thanked: 399 times

Re: Full disk scope for Quark?

Post by RodAstro »

Hi again forgot to say don't spend to much on it as Quarks don't seem to be very good at full disk stuff, maybe better to do mosaics.
I am with you on flats for full disk, I have never been happy with them, they work fine on high res, maybe its the Quark.
I always correct mine in Ps far easier.

Cheers Rod


User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

cmas wrote: Thu Jul 29, 2021 4:25 pm All my full disk H-alpha images and animations taken during 2021 are without any flatfield correction. You can see some uniformity and flat field related issues e.g. in my animations. So take a look at them and you'll see what level issues I have.

I tested recording flats via unfocusing (which works nicely with higher magnification) but the tracking in my SolarQuest is not good enough for full disk flats so I just don't take them.
Thanks Tommi,
I think your full disk look really good. I'd be happy if I got that kind of quality. Also you optics is really clean. Mine is plagued with dust bunnies no matter how I clean the optics I cannot seems to fix all of them so I think I'd need a flat for calibration.
RodAstro wrote: Thu Jul 29, 2021 4:55 pm Hi Minh

A 50 mm finder/guider works well.
You can put a reducer before the Quark I do this on my 150mm f15 refractor to bring the image scale down, not for full disk, but it would work on a smaller scope.
I use a Pixco 0.7 camera reducer taken out of the camera fitting and then fitted into a 58mm extension tube to adapt it to my quark front, the beauty of this reducer is, it does not alter the focus point and it is all air spaced so no heat problems.
You could fit one to the back of a camera lens.
I have been using a 50mm finder with a 0.5 cheapo reducer onto an ASI174mm after the quark for full disk it seems to work ok, remember its monochromatic light so you don't need any fancy corrected reducer.
I would recon your reflection will come from the lens, probably not to many coatings inside. have you stopped it down to get a higher f ratio?
On my Solar Scout SS60-DS I have to stop it down to 30mm to get anything like a good image and when you work it out that's about F32 at the etalon so near the Quarks optimum.

Cheers Rod
Thanks, Rod.
I stopped the lens down to F7 with the internal aperture. Maybe that's the source of the reflection. Figure I would try to mask the lens before objective and see if the problem persists


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

RodAstro wrote: Thu Jul 29, 2021 5:03 pm Hi again forgot to say don't spend to much on it as Quarks don't seem to be very good at full disk stuff, maybe better to do mosaics.
I am with you on flats for full disk, I have never been happy with them, they work fine on high res, maybe its the Quark.
I always correct mine in Ps far easier.

Cheers Rod
I agree that Quark are not designed for full disk. But I have limited budget and if there's a way to use the Quark for full disk instead of buying a new Lunt I'd prefer that. But thank you, I'll heed you advice and wont spend too much on it.


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
RodAstro
Im an EXPERT!
Im an EXPERT!
Posts: 385
Joined: Sun Oct 29, 2017 9:51 pm
Has thanked: 286 times
Been thanked: 399 times

Re: Full disk scope for Quark?

Post by RodAstro »

I have a feeling the reflection may be caused by the close proximity of the rear camera lens to the Quarks first blocking filter.
I had the same thing when trying to make a Ha unit with Bob's filters when putting collimating lenses close to the filter even though they were coated.
The blocker is basically a mirror so reflects everything back at the lens. Probably some tilt issues as well with the camera lens so it goes off to one side, camera lens optics tilt all over the place far worse than a SCT mirror flop.

Cheers Rod


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10248 times
Contact:

Re: Full disk scope for Quark?

Post by marktownley »

I use a 60mm f6 scope as my donor scope for full disks - here's the one I took yesterday...

ImageHa-FD-DS by Mark Townley, on Flickr


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
User avatar
minhlead
Almost There...
Almost There...
Posts: 682
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 738 times
Been thanked: 1104 times
Contact:

Re: Full disk scope for Quark?

Post by minhlead »

RodAstro wrote: Fri Jul 30, 2021 11:34 am I have a feeling the reflection may be caused by the close proximity of the rear camera lens to the Quarks first blocking filter.
I had the same thing when trying to make a Ha unit with Bob's filters when putting collimating lenses close to the filter even though they were coated.
The blocker is basically a mirror so reflects everything back at the lens. Probably some tilt issues as well with the camera lens so it goes off to one side, camera lens optics tilt all over the place far worse than a SCT mirror flop.

Cheers Rod
Now that you put it like this, I think that may very well be the case here. The last element comes extremely close to the Quark's nose blocking filter.
marktownley wrote: Fri Jul 30, 2021 11:37 am I use a 60mm f6 scope as my donor scope for full disks - here's the one I took yesterday...

ImageHa-FD-DS by Mark Townley, on Flickr
The shot is excellent, Mark. I saw your post the other day. I'd be very happy if I can come close to this kind of image quality. I can see that you mentioned that you replaced the expensive telecompressor (the solarspectrum 0.7x telecompressor?) For a cheapo reducer and got good result. Could you please give me a link to where you purchased that reducer? Thanks!


Minh.
Loves from Viet Nam <3
My gear:
Scope: SkyRover (Kunming Optics) 152mm F/6 Doublets
Mount: JTW Tridents GTR
Camera:
PlayerOne Apollo M-Max
Quark Chromosphere Doublestacked with PST etalon
RodAstro
Im an EXPERT!
Im an EXPERT!
Posts: 385
Joined: Sun Oct 29, 2017 9:51 pm
Has thanked: 286 times
Been thanked: 399 times

Re: Full disk scope for Quark?

Post by RodAstro »

That's a excellent full disk from a Quark Mark.
What make of scope was it? My 60mm f3.8 lens on the Solar Scout is awful.

Cheers Rod


User avatar
marktownley
Librarian
Librarian
Posts: 42274
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 20442 times
Been thanked: 10248 times
Contact:

Re: Full disk scope for Quark?

Post by marktownley »

Its a technosky 60mm f6. I use a Lunt 50 etalon on the end and then double stack it with the Quark.


Image
http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!
RodAstro
Im an EXPERT!
Im an EXPERT!
Posts: 385
Joined: Sun Oct 29, 2017 9:51 pm
Has thanked: 286 times
Been thanked: 399 times

Re: Full disk scope for Quark?

Post by RodAstro »

Thanks Mark
Very interesting

Rod


Post Reply