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Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 12:05 pm
by OlegLviv
Hello friends am not alone=)
Yes yes single lens that I sad collimation lens also works as a Barlow 1.89 x and the objective is F4.2
Can Do It this modification!
After two months of work, such a miracle turned out!
In my mind its very good modification with my 127/9 refractor!
Better PST 2 modification!
Such a larger sweet spot in the 35mm standard than in the PST 20mm
I will show a comparison later

Refractor Achromat 127/F9 + Lunt 60mm + Coronado BF15
Camera:Apollo MAX M 432
Barlow Lens: Televue Powermate 2.5x/Televue Powermate 4X
Baader UV/IR CUT + Astronomik 6nm Ha

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 5:08 pm
by OlegLviv
A few photos my stack modification!

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 5:10 pm
by OlegLviv
Such a larger sweet spot in the 35mm standard than in the PST 20mm

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 5:10 pm
by pupak
Hi Oleg,
many thanks for the samples. The photos are very nice. Am I to take it that you used the LS60THa with that collimating lens for a simple 60/F4.2 objective and got such beautiful results?
Can you share the exact setting of the etalon position in relation to the focal point your 127/F9 ?
This is a very important value and your result is really a small miracle.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 5:19 pm
by MalVeauX
mami813 wrote: Tue Jul 26, 2022 2:07 am Did the double stack version succeed?
Hi,

Yes, the first iteration with a Siebert Optic telecentric worked, however it had a sweet spot so it was determined that it was not a true telecentric. I replaced it with a Baader TZ4 4x telecentric and the sweet spot was gone and it worked very well. I also had to change the location of the ITF and blocking filter, for vignette reducing purposes. It is no longer near the camera and is instead before the telecentric. This system is a collimated system with air spaced etalon followed by a telecentric system with air spaced etalon (I used my pre-meade PST etalon which is excellent contrast). Together when tuned, they do quite well in this configuration on the 150mm refractor with no electronics needed to tune. This also works on my Lunt 60 stock instrument as a double stack as well for full discs.

LuntPST_DS_TZ4_IMX174_Reducer_ImagingTrain_01.jpg
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Here's the real world view in FireCapture, the double limb gone and a nice wide FOV:

FC_LuntPST_DS_BaaderTZ4_IMX174_Reducer_06032022.jpg
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Here's the same imaging train back in the stock Lunt 60 OTA, as it's totally modular and reversible and can be used in either system. It just inserts. The spacing and focus is the same.

FullDisc_Solar_Lunt60DS_07152022.jpg
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Here are my latest double stack results with this system (some of these are mosaics, huge):

Image

Image

Image

Image

Image

Image

Image

Image

Image

Image


And the full discs (mosaics, but only 3~4 slices to make them, easy). Same imaging train, same camera, etc as above. Just in the Lunt 60 OTA as seen in the image above.


Image

Image

Very best,

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 5:53 pm
by OlegLviv
pupak wrote: Tue Jul 26, 2022 5:10 pm Hi Oleg,
many thanks for the samples. The photos are very nice. Am I to take it that you used the LS60THa with that collimating lens for a simple 60/F4.2 objective and got such beautiful results?
Can you share the exact setting of the etalon position in relation to the focal point your 127/F9 ?
This is a very important value and your result is really a small miracle.
Yes I use the LS60THa with that collimating lens for a simple 60/F4.2 .
The collimator lens needs to be at -264mm back focus. Don't use focal ratio to place the colliator, use a measured back focus value.
MalVeauX told me.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 6:21 pm
by pupak
I tried this etalon with -264mm back focus on AR90/F10 and the results were unusable. You are a lucky man. ;)

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 6:42 pm
by OlegLviv
pupak wrote: Tue Jul 26, 2022 6:21 pm I tried this etalon with -264mm back focus on AR90/F10 and the results were unusable. You are a lucky man. ;)
Man wats wrong you have Lunt 80mm Duble stack with 150mm refractor you are lucky =)))) :seesaw

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jul 26, 2022 9:29 pm
by MalVeauX
pupak wrote: Tue Jul 26, 2022 6:21 pm I tried this etalon with -264mm back focus on AR90/F10 and the results were unusable. You are a lucky man. ;)
Hi,

So the collimator in the previous Lunt 60 LS60THA vs the latest modular Lunt 60 LS60MT are different, I've had two people try to use their older Lunt and found the positioning to not work. The focal length of the singlet is different, but also the collimator is also differently positioned.

Finding the correct position for the collimator is the same process. Take the etalon chamber out of the singlet based OTA of the LS60THA and point the lens at the sun. Using a black piece of metal and a measuring instrument, find where the disc is at focus behind the lens. It should be equal the lens's actual focal length. Note that position. Measure from that point back into the light cone to the location where the collimator lens would be if it were reinserted into the OTA. That back focus distance is constant and that's where the collimator needs to be on any other lens and OTA. On the LS60MT it's around -264mm. The LS60THA is probably different, but again, measured the same way.

Very best,

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 3:07 am
by OlegLviv
pupak wrote: Tue Jul 26, 2022 6:21 pm I tried this etalon with -264mm back focus on AR90/F10 and the results were unusable. You are a lucky man. ;)
Sorry for not correct answer my friend told me how we are doing (-264mm back focus without 1.86 lens barlow which is not MalVeauX on his telescope)
You and I have 1.86 lens and the distance will be different than have MalVeauX Lunt 60.
You can see the correct distance on my drawing.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 5:49 am
by pupak
I tried both variants. Back focus -264 and then focus location identical to your image. Neither option yielded a usable result.
Probably 90/F10 is already beyond the limit of usability for collimation at F4.2.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 6:43 am
by OlegLviv
pupak wrote: Wed Jul 27, 2022 5:49 am I tried both variants. Back focus -264 and then focus location identical to your image. Neither option yielded a usable result.
Probably 90/F10 is already beyond the limit of usability for collimation at F4.2.
Ohhh you can see your result us? Your sweet spot!

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 7:48 am
by pupak
The sweet spot didn't happen. I couldn't even focus.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 7:55 am
by OlegLviv
pupak wrote: Wed Jul 27, 2022 7:48 am The sweet spot didn't happen. I couldn't even focus.
Perhaps you need to install a 30mm or 50mm or 80mm extension adapter or shorten the telescope, I cut mine OTA minus 70MM+- :band2

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed Jul 27, 2022 10:24 am
by Alto
Fascinating article and result.

Way beyond my capability but nonetheless impressive!

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Fri Sep 29, 2023 6:24 pm
by lsp1998218
OlegLviv wrote: Wed Jul 27, 2022 3:07 am
pupak wrote: Tue Jul 26, 2022 6:21 pm I tried this etalon with -264mm back focus on AR90/F10 and the results were unusable. You are a lucky man. ;)
Sorry for not correct answer my friend told me how we are doing (-264mm back focus without 1.86 lens barlow which is not MalVeauX on his telescope)
You and I have 1.86 lens and the distance will be different than have MalVeauX Lunt 60.
You can see the correct distance on my drawing.
Hi Oleg, thank you very much for the important information. Can I just simply understand that you only fit the distance from etalon to focus plane(148mm) to the new scope and become successful?

Best

Su

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Mon Jan 29, 2024 11:47 am
by LLichter
Thanks you marty for this post.

i did get this to work with a Meade Messier AR152L/1200.

Still have some tilt problems but it worka great.

haveing a lot of fun with this.

Dominik

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue Jan 30, 2024 1:07 pm
by OlegLviv
Nice hear you!

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Tue May 14, 2024 10:33 am
by DannyElfman
Hi there,
I might hope into the same boat.
I have a 127/1200 achromat refractor (Bresser one) and might get a Lunt LS60ThA.

I was wondering ... do we really have to cut the tube ? Would a 3D printed adapter be a good idea ? The Lunt part should be a lesser diameter than the OTA. That way, one can insert the Lunt part into the tube, reaching the focal point.
Not sure I'm clear but I think you get the gist ?

Another

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Wed May 15, 2024 5:21 am
by LLichter
DannyElfman wrote: Tue May 14, 2024 10:33 am Hi there,
I might hope into the same boat.
I have a 127/1200 achromat refractor (Bresser one) and might get a Lunt LS60ThA.

I was wondering ... do we really have to cut the tube ? Would a 3D printed adapter be a good idea ? The Lunt part should be a lesser diameter than the OTA. That way, one can insert the Lunt part into the tube, reaching the focal point.
Not sure I'm clear but I think you get the gist ?

Another
Hi.

You are correct thay you dont have to cut the tube as long as you find some other way to get the collimating lens at the right back focus.

I am curios to see how you will manage to insert the etalon housing including the pressure tuner into the OTA. :)

You should messure the back focus of your Lunt yourself. The mod by marty uses a Lunt60TM which might have a different back focus to the Lunt60THa.

Best Regards
Dominik

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Sat May 18, 2024 9:32 pm
by MalVeauX
DannyElfman wrote: Tue May 14, 2024 10:33 am Hi there,
I might hope into the same boat.
I have a 127/1200 achromat refractor (Bresser one) and might get a Lunt LS60ThA.

I was wondering ... do we really have to cut the tube ? Would a 3D printed adapter be a good idea ? The Lunt part should be a lesser diameter than the OTA. That way, one can insert the Lunt part into the tube, reaching the focal point.
Not sure I'm clear but I think you get the gist ?

Another
All that matters is that the collimating lens sits at -264mm with the Lunt 60 modular (its different with a different collimator system like the original Lunt 60). How you get it there doesn't matter. You could find a way to insert it without the focuser. You could use a barlow to pull focus out.

Or, don't use the Lunt 60 at all. Instead, use the Lunt 50 LS50Fha etalon, its external, with M90x1 threads and a telecentric and it will work without any special placement or focus limits. Much much easier.

You would do just do Objective -> Focuser -> 2" DERF (2" red filter) -> TZ4 (4x telecentric) -> M90x1 threaded plate adapter -> Lunt LS50FHa -> M90x1 threaded plate adapter -> blocking filter -> eyepeice/camera

20240423_125751.jpg
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20240423_125605.jpg
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HA_Lunt50Solo_102mmF28_IMX432_04232024.jpg
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Very best,

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Sun May 19, 2024 11:33 pm
by DavidP
Marty
Where did you have those aluminum threaded adapters made?
All the machinist in my town want ridiculous prices for this kind of work.

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Mon May 20, 2024 3:07 am
by KMH
DavidP wrote: Sun May 19, 2024 11:33 pm Marty
Where did you have those aluminum threaded adapters made?
All the machinist in my town want ridiculous prices for this kind of work.
Marty mentioned in another thread that the adapters were made by RAF Camera. They have them in stock.

Kevin

Re: Rear Mounted Lunt 60 Modular Mod (HA) | Complete

Posted: Thu May 23, 2024 12:28 pm
by Rob63
MalVeauX wrote: Mon Dec 27, 2021 3:48 pm Summary on focal-ratio to target on a donor scope, F7 to F8 as a range.

Ideal common refractor configurations for this (ED doublet or ideally just an achromatic doublet):

80mm F7 to F7.5 to F8
90mm F6.67 to F8
102mm F7
120mm F8
140mm F7
150mm F8

As a matter of interest, what would the effect of using a higher f/ratio donor scope rather than the f7-f8 suggested ? Sweetspot reduced?

Some examples would be: Skywatcher Evostar 120mm is f8.33 or Altair 102mm f11 with removable section for binoviewers