Lunt 40mm module help

[Radon86]

Hi All,

Maybe Mark Townley can help me ?
I saw this wonderful Double stack setup by Oak - see the details here:

viewtopic.php?t=37582

He stacked the Lunt 40mm after the Quark, and he posted a photo of it in the post.

Please, how do we obtain this Lunt 40mm unit ? How much would it cost ?

Thanks

Magnus

[EricF]

Hi Magnus,

So far, it seems only the scope is available. Least expensive version would be with the basic focuser and the 5mm blocking filter. US $675. Nothing is available from Lunt at the moment, although they seem to mention a DS module from time to time.

I've seen both an LS35 and an LS40 doubelstacked. Do a search of the forums. Both were accomplished by sacrificing a second telescope.

Keep your eyes open on the used market. One of us is bound to get aperture fever and buy something bigger.

Eric.

[marktownley]

Hi magnus.

I guess you would have to buy a ls40 scope and cannibalise the etalon from it. The same can be achieved with a pst etalon.

Mark

[Oak]

Hi Magnus,
The etalon just unscrews from the front of the Lunt 40mm. I bought the 40mm scope with the intent of using it this way and still having a quick conversion back to a grab and go full disk setup. It takes less than a minute to switch the configurations once you have all the parts. I think the full 40mm scope with blocker only end up costing something like 300 us dollars more than the blocker alone if you buy from Lunt.

-Derek

[Oak]

*Of course there is also a custom enclosure for the Lunt etalon. The WHITE 50mm offered by Lunt does not require this but is considerably more expensive.

[Radon86]

Hi Magnus,
The etalon just unscrews from the front of the Lunt 40mm. I bought the 40mm scope with the intent of using it this way and still having a quick conversion back to a grab and go full disk setup. It takes less than a minute to switch the configurations once you have all the parts. I think the full 40mm scope with blocker only end up costing something like 300 us dollars more than the blocker alone if you buy from Lunt.

-Derek

Hello Derek,
So I can just a basic LS40 with a B500 blocking filter like this:

https://www.harrisontelescopes.co.uk/ac ... wREALw_wcB

Then how do you fit the Lunt etalon to the Quark? Do you need a special adaptor. What about adapting the Lunt to the camera. I see you have an adaptor to fit the camera ? Is this a special item as well ?

Many thanks.

Magnus

[Oak]

Hi Magnus,

Here are the components in the system. I also described the system in this post with a few more photos: viewtopic.php?t=35857

1. Sol
2. Telescope objective/tube/focuser (I have used an ST80, AT102ED, and Bresser AR127L all with success)
3. 2-inch Baader H-Alpha 35nm filter as ERF
4. 2 inch extensions (x2)
5. Quark Chromosphere (Standard with built-in 4.2x telecentric and blocker)
6. Quark to T2 adapter
   (FLO:https://www.firstlightoptics.com/adapte ... to-t2.html)
7. Custom Etalon Enclosure for Lunt 40mm etalon (RAF Camera)
   
   Insides of enclosure blackened with aluminum black (would recommend adonizing though):
   https://www.brownells.com/gunsmith-tool ... d4941.aspx
8. Lunt 40mm Etalon from 40 mm dedicated telescope
   https://luntsolarsystems.com/product/lu ... telescope/
9. Tilt adapter
   https://agenaastro.com/zwo-t2-tilter-adapter-ii.html
10. Eyepiece holder
    https://agenaastro.com/blue-fireball-1- ... -e-10.html

Quark with T2 adapter, Lunt 40mm etalon in enclosure, tilt adapter, and eyepiece holder.


The whole setup:


Make sense?

Best,
Derek

[Radon86]

Hello Derek,

That is brilliant ! I will print this out and work out all the details now.

Thank you so much.

Magnus

[Oak]

You're welcome! Getting the etalon enclosure designed and machined and waiting to see if my measurements were correct was the most tenuous part.

[Oak]

FYI: The etalon adapter/enclosure is now listed on the RAF camera website.

https://rafcamera.com/adapter-lunt-40mm

[pupak]

Combining these two types of etalons seems like a very good idea to me. I'm also thinking about that, but I want to use the Quark combo and build the etalons the other way around. As the first LS40 and Quark behind it. I would place the blocking filter at the end of the optical path in front of the camera. To change the aperture on the F30, I would use the TZ4 or TZ3 depending on the focal length of the lens. The TZ3 has a clean aperture of 46mm, which seems ideal to me for the LS40.
Does this solution have any visible weakness? Thanks for every response.

[Oak]

Doesn't the combo have the blocking filter built in? Aside from that, I don't think it matters which order they are in if they are both in the telecentric beam. That does widen the fwhm on the air-spaced Lunt etalon though.

[pupak]

I am a man of action, so the work is done.
It seems to work well, but the conditions are downright terrible.

[Oak]

Awesome. Beautiful looking setup. The spacing after the quark is for the telecentric? Did you try it visually?

[pupak]

The set is: TZ3x, LS40, Quark, blocking filter, camera. I haven't tried it visually. There was very little time.

[Oak]

I bet you could use a Lunt blocking filter instead of the quark blocker if you had a bigger one.

[pupak]

The Lunt has a narrower band but I only have a 12mm filter. He vignettes in the telecentric volume. I have cameras with a larger angle than 12mm. The Quark filter is perfectly fine.

[Oak]

Aren't blocking filters usually before the etalon in mica systems? Any idea why that is? Does the blocker serve as a secondary ERF for the polarizers in the mica stack? It would be nice to get a 3x telecentric to use with my standard quark but I've worried about then needing to use a (Lunt) blocker after the etalon.

[pupak]

The classic Quark is designed as an eyepiece, so it has a blocking and DERF filter before the telecentric element.
Nothing prevents you from replacing the telecentric element with another and using a blocking filter from LUNT with an eyepiece or camera.
Before Quark I put 2" UV/IR cut, or H-a 35nm.

[marktownley]

The set is: TZ3x, LS40, Quark, blocking filter, camera. I haven't tried it visually. There was very little time.

You don't need to use the Lunt blocking filter at all, the blocker in the Quark alone will be fine.

[pupak]

In order to prevent misalignment due to deflection, I created a rigid lattice coupling. The telecentric member is located in a 2.5" elevator, so the elevator load is minimal.

[Oak]

So nice!

[Rusted]

Your metal fabrication is always truly excellent.

I was going to build a similar skeletal [?] extension for my own set-up.
Mounted on an enlarged backplate but using much longer rods or tubes than yours.
To support the components nearer the camera to combat the usual sagging.

There is some complication with my method due to linear focusing movement.
It would require a smoothly sliding linear bearing for the tail end and camera support.
There is also the matter of easy accessibility for the Lunt pressure tuning and focusing knobs.

[Oak]

Hi All,

I made a 3D-printed version of the Lunt 40mm etalon adapter with the .stl files available for free here:

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

-Derek

[Radon86]

Brilliant,
Thanks Derek !!
I will prepare my workup for this adaptor and double stacking my Quark.

Magnus