Quark + Lunt 40mm double stack at 102mm aperture

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
Post Reply
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Hi All,

Since this forum is the major source of information for this mod, I wanted to share the details here. I recently acquired a Lunt 40mm scope for quick full disk views to complement my Quark. It’s great. That aside, one of the secondary goals of getting the 40mm was to try to put the air-spaced etalon in the telecentric beam after the Quark for a double stack – similar to the Quark+PST mods here. The mod also needed to be quickly reversible so I can still use the 40mm as a grab-and-go scope. I had a custom etalon enclosure machined to hold the Lunt40 after the Quark and I am pretty happy with the end result. Details and a few images below.

The etalon enclosure:
The Lunt 40mm etalon screws on to the 40 mm scope with M60x1 thread. I had an adapter machined to accept the etalon between standard T2 threads. This was based on some of the adapter designs already on this board and those sold by Beloptik.

Adapter design:
Image

Images below (aluminum black used for internal parts).

Image

Image

The adapter was then placed between a T2-to-Quark adapter from FLO and a blue fireball T2-1.25 inch eyepiece holder and attached to the quark.

Assembled and in place in Astrotech AT102ED:
Image
(AT102ED, Badder 35nm H-alpha, extension tubes, Quark, Lunt 40mm, diagonal, Arcturus binoviewers with 25mm Plossls and bino bandits)

Image

Visually, I am quite pleased with the results, although I have only had this contraption out for a few sessions. Much improved contrast at the cost of some brightness, particularly on proms. The double limb is greatly diminished though.

The images below are from 2 brief imaging attempts. Exposure times ~5ms with low gain settings on my non-standard camera (HIKVISION machine vision camera) and ~30 second captures taken at 60-100fps. Aligned in Autostakkert, best 5%, deconvolved and unsharp masked in IMPPG. No flats or flat field correction. All the histograms are linear stretched except the one noted. You can see some vignetting at the edge of the images – they are essentially the maximum field of view for this configuration.

AR2995_2994_2993:
Image

Image

Image

Just a little lift on the histogram for the proms on this one:
Image

Thoughts? I haven’t tried clocking the etalons yet so that is probably next on the list.

Best,
Derek


User avatar
marktownley
Librarian
Librarian
Posts: 43349
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 21946 times
Been thanked: 11183 times
Contact:

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by marktownley »

Very promising results Derek. Clocking etalons always finds a best (and worst!) spot for them...


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
MalVeauX
Way More Fun to Share It!!
Way More Fun to Share It!!
Posts: 1870
Joined: Tue May 09, 2017 7:58 pm
Location: Florida
Has thanked: 1261 times
Been thanked: 1474 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by MalVeauX »

That chamber is awesome! Mind sharing where you had it machined? 40mm front mounted etalons that fit in a chamber like that have lots of potential and are inexpensive relative to their quality for rear-mounted options with a clear 40mm aperture. The air spaced etalon will improve with longer and longer focal-ratio, it doesn't fall off until closer to F100. Mica spaced etalons start to flatten out on gains after F50~F60 in telecentric cone. So if you want to tighten things up, longer focal ratio and use a reducer at the camera for sampling. Other than that it's a dance of tuning. Getting the Quark on band first would be ideal, so you can then real time adjust the Lunt 40 etalon and just watch the limb. If the double limb goes away, you're on band with both. I'm not sure clocking will matter much on this arrangement.

Very best,


User avatar
Radon86
Almost There...
Almost There...
Posts: 788
Joined: Sat Mar 23, 2019 10:05 pm
Has thanked: 763 times
Been thanked: 665 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Radon86 »

Hi Derek,
I also have a Quark, and am thinking of getting a Lunt 40mm scope. Which scope version did you have ? blocking filter size. How is the helical focuser ?
Also how much does the adaptor cost to fit the Quark ?

Thanks
Magnus


Solar: H-alpha": Quark Chromosphere filter; Baader white light filters
Scopes: Altair Astro Travel ED70mm (F 420mm, D=70mm);; Skywatcher 90mm (F 910mm D=90mm); GSO focuser;;Altair Astro 60mm guidescope (D=60mm,F=225mm)
Cameras: ASI120mm-S,ASI174mm
Mount: SW HEQ5 Pro, SW EQ3 Pro Synscan (SW = Skywatcher),Vixen Polarie tracker (portable setup)
Accessory: SW Auto-focuser
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Thanks! Down the road, I will probably try to use the enclosure to place the etalon between digerging and converging lenses as opposed to within a telecentric - The T2 threads should make this possible with off-the-shelf parts. That's a more involved project for a differnet time though...

@ Marty: I just tuned the quark to the usual setting and then added the 40mm etalon after it, then looked for the brightest image. Probably the double limb is a more reliable measure of on-band performance, but it was very diffucult to see in general. When I stop the scope down to 80mm (f8.9 vs f7) it definitely gets more contrasty at the expense of some brightness. I'm already using a 0.5x reducer at the camera for better sampling. Really bad newton rings otherwise anyway.

I had the adapter machined at Raf Camera. They have a custom adapter link that I stumbled upon. I roughed something out and over a few emails the finished product emerged. Raf was very responsive and the adapter was made within about 2 days of finalizing the design. Shipping then took >1 month due to all the things that started happening in that part of the world just after my order.

@ Magnus: I have the B1200. It is overkill, but I had planned to mod the scope when I bought it so got a bigger blocking filter for future compatibility. There is a discount on the blockers when you buy with a scope. The helical focuser is ok. There is definitely some sag when I put binoviewers or the quark on the scope, but it still works just fine. It's really nice to double stack with the quark (replace blocker with quark) - still passes a full disk. The adapter/enclosure was 150USD+shipping.

-Derek


torsinadoc
Almost There...
Almost There...
Posts: 843
Joined: Sat Apr 08, 2017 2:53 pm
Has thanked: 1640 times
Been thanked: 878 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by torsinadoc »

Excellent mod. I am considering something similar for my daystar. I’m not completely happy with my pst daystar double stack. How did it effect your camera exposure and gain? Did you remove the Lunt ERF since it’s behind the quark?


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Thanks. I don't have my prior exposure times handy, but will do a comparison next time I image. The photos above were taken at 5ms exposure with a low gain setting. I did not remove the ERF from the lunt etalon as I wanted to keep the mod quickly reversible. It's plenty bright for visual, but that may be dependent on how bright my quark is. Will update then I have some concrete numbers.


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Hi All,

Just wanted to update this thread with a few things:

I have used this double stack filter system up to 127mm now with good results:

Image

Image

The aluminum etalon adapter is now available commercially from RAF camera:
https://rafcamera.com/adapter-lunt-40mm

I have also now made a 3D-printed version of the adapter with the .stl files available for free here:

https://www.printables.com/model/348580 ... -enclosure

The 3D-printed adapter is basically identical to the aluminum one, but the walls have been beefed up to ~5mm for added strength given the weaker material used. The assembled enclosure has T2 (M42x0.75) threads on both ends. I made two versions of the etalon holder that bolts into the enclosure: one with a female T2 thread (clear aperture 42mm) and one with a male T2 thread (clear aperture 34mm). The Lunt 40mm etalon attaches via M60x1 thread. There are 6 M5x0.8 screws to hold the two parts together, although just using three is probably adequate. The example below was printed in nylon by a commercial service.

Top of etalon holder (male and female T2 versions):

Image

Bottom/inside of etalon holder without etalon:

Image

Bottom/inside of etalon holder with etalon attached via M60x1 thread:

Image

Enclosure with 6 M5x0.8 screws:

Image

Full enclosure assembled with etalon:

Image

3D printed enclosure attached to Quark and size comparison with aluminum version. The etalon enclosure modules screw together so could be used as a double (or triple?) stack.

Image

-Derek


User avatar
marktownley
Librarian
Librarian
Posts: 43349
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 21946 times
Been thanked: 11183 times
Contact:

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by marktownley »

Great stuff!


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!
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Thanks. I should mention that the 3d printed version is a result of seeing Averton's success with a similar approach.


User avatar
minhlead
Almost There...
Almost There...
Posts: 704
Joined: Sun Apr 25, 2021 9:36 pm
Location: Ha Noi, Vietnam
Has thanked: 759 times
Been thanked: 1136 times
Contact:

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by minhlead »

Oh this is great!
I find this guy online doing exactly what you did and he got terrific result: excellent double limb supression, extremely even fov.
And he claims that after mounting the Lunt behind the Quark, he no longer tune the Lunt since tuning the Lunt "make no difference". I am baffled. In your experience, is it true?
Attachments
Screenshot_20230705_134629_Facebook.jpg
Screenshot_20230705_134629_Facebook.jpg (697.14 KiB) Viewed 5933 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
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Tuning/tilting does make a difference to me, but less than with single stack. (You are just trying to maximize brightness and evenness to match the two etalons) . Putting the air spaced Lunt etalon in the telecentric beam behind the quark does blue shift the etalon slightly, which takes the place of some tilt.


User avatar
AndreaGirones
Oh, I get it now!
Oh, I get it now!
Posts: 28
Joined: Sat Jun 10, 2023 11:54 am
Has thanked: 50 times
Been thanked: 113 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by AndreaGirones »

Hello
Just letting you know I apreciated this thread very much and was able to order the adapter and set up my Lunt 40 etalon with my quark. Still waiting for some nice seeing but here are some of my images so far. :bow :bow

Image
Image :hamster:
Attachments
sunspot 3363 copy.jpg
sunspot 3363 copy.jpg (762.62 KiB) Viewed 5784 times
setup.jpg
setup.jpg (787.09 KiB) Viewed 5784 times


Andrea
Lunt40 mm
Starfield Optics 102 scope
Daystar Quark Chromosphere
Lunt 1200 Clacim K blocking filter
ASI174MM ASI290MM
instagram https://www.instagram.com/andrea_girones/
Flickr: https://flic.kr/ps/429jub
Astrobin : [url]https://www.astrobin.com/users/Agirones/[url]
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Thanks. Glad it's working for you. Also very gratifying to see others trying this approach. That's a nice looking setup and image!


DavidP
Almost There...
Almost There...
Posts: 518
Joined: Sun Mar 08, 2020 9:25 pm
Location: Austin Texas
Has thanked: 169 times
Been thanked: 389 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by DavidP »

Very nicely done. Thanks for sharing the details.
Does adding the Lunt change the focus?


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

Thanks. It does change focus, but very little. Less than 1cm. I have had two Lunt 40s behind the quark as a triple stack and there was still minimal focus shift.


vineyard
Almost There...
Almost There...
Posts: 599
Joined: Wed Feb 02, 2022 11:08 am
Has thanked: 932 times
Been thanked: 895 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by vineyard »

Gosh I'm very late to this mod - thanks for sharing. The etalon needs parallel light doesn't it - how the does the quark generate that (I thought the light that comes out of the quark is a converging beam) or am I missing something? Thank you!


User avatar
marktownley
Librarian
Librarian
Posts: 43349
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 21946 times
Been thanked: 11183 times
Contact:

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by marktownley »

vineyard wrote: Sat Sep 02, 2023 9:40 am Gosh I'm very late to this mod - thanks for sharing. The etalon needs parallel light doesn't it - how the does the quark generate that (I thought the light that comes out of the quark is a converging beam) or am I missing something? Thank you!
The light coming out of the back of the Quark is telecentric, so, it works with an air spaced etalon for this purpose.


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!
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

This quark has the built in telecentric. Also works with Lunt40+TZ4+blocker and no quark better than I thought would. I've been trying just the Lunt 40 mm etalons with a negative meniscus lens and refocusing doublet lately and this also works as it should, but you get a sweet spot.


vineyard
Almost There...
Almost There...
Posts: 599
Joined: Wed Feb 02, 2022 11:08 am
Has thanked: 932 times
Been thanked: 895 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by vineyard »

Thanks both. Ah I see - I have the combo quark which doesn't have the built in telecentric. I guess this mod won't work for my kit then - ah well. Cheers!


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

vineyard wrote: Sat Sep 02, 2023 2:46 pm Thanks both. Ah I see - I have the combo quark which doesn't have the built in telecentric. I guess this mod won't work for my kit then - ah well. Cheers!
It will work well with the quark combo. A telecentric amplifier is required before the combo anyway. How else are you getting to F30+?


vineyard
Almost There...
Almost There...
Posts: 599
Joined: Wed Feb 02, 2022 11:08 am
Has thanked: 932 times
Been thanked: 895 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by vineyard »

Oak wrote: Sat Sep 02, 2023 8:34 pm It will work well with the quark combo. A telecentric amplifier is required before the combo anyway. How else are you getting to F30+?
That's interesting, thanks. I've been using a 2.5x powermate on an f8.6 frac or an f6.5 frac to get to f21 and f16.

Here fwiw is what I get running it at f16:

Image

Image

I do have an SF50 etalon which I've always wanted to try and run at the back of a 4" frankenscope (even just single stack) but I would need to somehow thread a telecentric in front of it, and then the focusing doublet after it and I just can't mount something that long. So I think maybe a LS50+quark may be a more feasible direction for my kit.

But on my to do list is to put the powermate and quark at the back of the SF50 on a 3" scope. I tried it briefly but I have to take the back blocking filter out I think b/c the image came out very very dark.

Cheers,

Vin


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

A 4x telecentric (baaderTZ4) would give you tighter bandpass with the quark combo. Definitely worth the decrease in overall intensity. Ideally, you want to be around f40 for the mica etalons.

The quark+telecentric should also work on the back of another H-Alpha scope. The quark replaces the blocking filter in this configuration.


vineyard
Almost There...
Almost There...
Posts: 599
Joined: Wed Feb 02, 2022 11:08 am
Has thanked: 932 times
Been thanked: 895 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by vineyard »

Thanks - I will look into the TZ4 b/c that would be very interesting to see the tighter bandpass. The difference in resolution between the 4" with a quark and the SF50 is palpable. The SF50 has much better contrast though, so anything that can lead to a better combination of the two, resolution + contrast, can only be a good thing. Cheers, tips much appreciated!


EboO
Ohhhhhh My!
Ohhhhhh My!
Posts: 64
Joined: Mon Feb 20, 2023 7:25 pm
Has thanked: 6 times
Been thanked: 18 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by EboO »

Very interesting mod, i'm near to try it too.
Just a question about etalon, do all etalons from Lunt 40 are equals or is there some (lot ?) of dispersion ?
Last question is there a backfocus to respect ?

And please do you know why rafcamera adapter isn't adapted to Lunt 40 DS module (a little cheaper...) ?


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

There is certainly variability in the Lunt etalons, particularly with respect to how much tilt they require to come on band (CWL). Backfocus is not a big issue here because the etalon is in the telecentric output of the quark.

There is a Lunt40 DS (and Lunt 35mm) version of the raf camera adapter. Just search the site for "Lunt". The non DS Lunt 40 is about 5mm shorter than the DS version because of the addition of the thread adapter in the later module.


EboO
Ohhhhhh My!
Ohhhhhh My!
Posts: 64
Joined: Mon Feb 20, 2023 7:25 pm
Has thanked: 6 times
Been thanked: 18 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by EboO »

Thanks Oak.
So no matter for backfocus with quark and same with a TZ ?
Is there a difference of quality between etalon of Lunt 40 SS and DS ?


Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

There is a very small change in focus plane and I have had two Lunt 40s in series after the quark (triple stack) with no problem focusing.

I don't think there is a quality difference between the ss and ds etalons. They appear to be the same thing.


KrisJot
The Sun?
The Sun?
Posts: 2
Joined: Thu May 30, 2024 7:58 pm
Has thanked: 1 time
Been thanked: 1 time

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by KrisJot »

Hi All,

I'm new here:-).
Lately I bought Lunt 40mm SS, magnificent scope, but inspired by @Oak posts I felt aperture's hunger:-).

I would like to try to combine the etalon from my Lunt 40 one of those scopes: WO80ED F7/TS102ED F7/ Bresser 102mm F10 Achro.
I don't have a quark, I would like to use a telecentric barlow instead to make beam parallel (ES, TV or 2" Siebert Optics OCA).
The optical path would initially look like this.
Refractor -> Baader HAlpha 2" ERF filter -> telecentric barlow -> etalon with enclosure -> blocking filter

Does this make sense?

Kris


User avatar
marktownley
Librarian
Librarian
Posts: 43349
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Has thanked: 21946 times
Been thanked: 11183 times
Contact:

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by marktownley »

KrisJot wrote: Thu May 30, 2024 10:08 pm Hi All,

I'm new here:-).
Lately I bought Lunt 40mm SS, magnificent scope, but inspired by @Oak posts I felt aperture's hunger:-).

I would like to try to combine the etalon from my Lunt 40 one of those scopes: WO80ED F7/TS102ED F7/ Bresser 102mm F10 Achro.
I don't have a quark, I would like to use a telecentric barlow instead to make beam parallel (ES, TV or 2" Siebert Optics OCA).
The optical path would initially look like this.
Refractor -> Baader HAlpha 2" ERF filter -> telecentric barlow -> etalon with enclosure -> blocking filter

Does this make sense?

Kris
Hi Kris

Welcome to the forum. Start a new thread please.

Mark


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!
Oak
Ohhhhhh My!
Ohhhhhh My!
Posts: 160
Joined: Mon Feb 07, 2022 6:16 pm
Has thanked: 307 times
Been thanked: 268 times

Re: Quark + Lunt 40mm double stack at 102mm aperture

Post by Oak »

This approach will work, but most would suggest a full aperture ERF for safety. You will want to be at f40+. The baader TZ4 works well. You will be at about 0.9 angstroms fwhm.


Post Reply