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lunt 50 mod

Posted: Sun Apr 09, 2017 2:52 pm
by DSobserver
After many years dealing with inconsistent Ha area with my PST mod, I decide to move to a lunt 50 mod.

Luckily my152/900 scope is close to lunt 50 f/d ration, so no barlow is needed!

I was also looking for a fully screw system.

here is the result :
Image

As you can see I also take the opportunity to connect a jmi focus system far better than original one!

Re: lunt 50 mod

Posted: Sun Apr 09, 2017 3:39 pm
by marktownley
Nice mod there!

Re: lunt 50 mod

Posted: Wed Apr 12, 2017 8:20 pm
by Valery
The sweet spot size should be about the same as with a PST Mod-2. Both etalons are air-spaced and both have the same working diameter - 20mm. The only advantage is the possibility to move the CWL of the etalon to blue and red wings.


Valery

Re: lunt 50 mod

Posted: Sat Apr 15, 2017 6:08 pm
by zorgdotnl
That's cool!!! :bow :bow :bow Do you have some images taken with it?

Re: lunt 50 mod

Posted: Sun Apr 16, 2017 1:52 pm
by DSobserver
yes here : http://www.webastro.net/forum/showthread.php?t=147279

valery,
you're probably right but it is less detectable and scope is f6 working vs f10 for pst mod!

Re: lunt 50 mod

Posted: Wed Apr 19, 2017 6:56 pm
by DSobserver
just measured : 24mm!

Re: lunt 50 mod

Posted: Wed Apr 19, 2017 7:00 pm
by marktownley
DSobserver wrote: Wed Apr 19, 2017 6:56 pm just measured : 24mm!
Always very useful to know, thanks! :)

Re: lunt 50 mod

Posted: Mon Oct 23, 2017 7:44 pm
by aboy
DSobserver wrote: Sun Apr 09, 2017 2:52 pm After many years dealing with inconsistent Ha area with my PST mod, I decide to move to a lunt 50 mod.

Luckily my152/900 scope is close to lunt 50 f/d ration, so no barlow is needed!

I was also looking for a fully screw system.

here is the result :
Image

As you can see I also take the opportunity to connect a jmi focus system far better than original one!
Hello DSobserver I have a question:

Do you think the specs of your 152 are the same from the TS152 telescope? https://www.teleskop-express.de/shop/pr ... uszug.html

I have years trying to do a PST modification but I fail in my first one and got disappointed of myself and stop trying that. But, I like the ide ato make a 152 telescope and lunt modification.

If is possible can you share some more pictures and specs of your modification?

I'm sorry if I bother you with my request.

Thank you :bow

Re: lunt 50 mod

Posted: Fri Oct 27, 2017 7:22 pm
by DSobserver
hello

TS scope is same as tecnosky one

lunt 50 mod is really easy it is a M68 screw same as the focuser from the scope! You'll immediatly get 95% of the mod.

Next if you want to change lunt focuser and get perfectly same distance between focus point and filter, you'll need some specific adapter.

I could comare visually this mod with 8" HAT : my "cheap" mod was impressive!

Re: lunt 50 mod

Posted: Fri Oct 27, 2017 7:23 pm
by DSobserver
of course I also add an internal 75mm erf!!!

Re: lunt 50 mod

Posted: Fri Oct 27, 2017 8:46 pm
by marktownley
Hmmm. M68 on the lunt 50. That does make things interesting in the mod department...

Re: lunt 50 mod

Posted: Sun Oct 29, 2017 5:55 pm
by aboy
DSobserver wrote: Fri Oct 27, 2017 7:23 pm of course I also add an internal 75mm erf!!!

DSobserver wrote: Fri Oct 27, 2017 7:22 pm hello

TS scope is same as tecnosky one

lunt 50 mod is really easy it is a M68 screw same as the focuser from the scope! You'll immediatly get 95% of the mod.

Next if you want to change lunt focuser and get perfectly same distance between focus point and filter, you'll need some specific adapter.

I could comare visually this mod with 8" HAT : my "cheap" mod was impressive!
Cool. I have save for a TS telescope I do need to buy it.

About the focuser for the Lunt. Which focuser are you using?
Can you post more pictures from your mod?

I'm really interested because my last PST mod was a disaster and I ended mess up the etalon.

I don't have a internal ERF but I have a 100mm ERF.

Also I notice that in your picture you using a Coronado blocking filter.

Please let me know if you can post more pictures and if you can add more specs on the focuser and the mod. I'm drying to do a mod that actually woks for me.

Thank you

Re: lunt 50 mod

Posted: Sun Oct 29, 2017 5:56 pm
by aboy
marktownley wrote: Fri Oct 27, 2017 8:46 pm Hmmm. M68 on the lunt 50. That does make things interesting in the mod department...
I'm sorry.

What do you mean with that?

Re: lunt 50 mod

Posted: Sun Oct 29, 2017 6:06 pm
by marktownley
There are lots of M68 adapters available...

https://www.teleskop-express.de/shop/ad ... /OK/page/1

Re: lunt 50 mod

Posted: Sun Oct 29, 2017 6:30 pm
by aboy
marktownley wrote: Sun Oct 29, 2017 6:06 pm There are lots of M68 adapters available...

https://www.teleskop-express.de/shop/ad ... /OK/page/1
Thanks

Re: lunt 50 mod

Posted: Thu Nov 02, 2017 8:44 am
by DSobserver
Hello

For me bf10 or 15 are clearly the best ones on the market : brightness and contrast

Regarding Focuser for me Lunt hélicoïdal Focuser is a real Che..

I had a Jim motor Focuser at home and asked for an adapter

In your case I wouldn’t focus to much on this part of my mod otherwise you can go for this one :
https://luntsolarsystems.com/product/1- ... h-focuser/

Again it’s the most important easiest mod : unscrew ref Lunt filter and screw it on ts scope at minimum focus point = done!

Regarding erf I fix it in the Focuser tube
You’ll easily find on solarchat how to fix yours!

I ve no access to my scope for the moment....

Re: lunt 50 mod

Posted: Sun Nov 12, 2017 4:52 am
by marktownley
I've just got a Lunt50 myself - no plans to mod it at this stage, just full disks, but to add to the discussion, the thread size at the focuser side of the Lunt etalon is the same as that on the back of the Daystar Quark, so there are plenty of off the shelf adapters (eg this one http://astrograph.net/epages/www_astrog ... ts/AGRAQT2 ) to get a T2 fitting for various connection options...

Re: lunt 50 mod

Posted: Sun Nov 12, 2017 6:56 pm
by DSobserver
good info!!!

Re: lunt 50 mod

Posted: Wed Nov 22, 2017 5:50 pm
by aboy
Thank you guys.

I will start to buying the refractor maybe my next month and the other stuff I need and for last the 50mm Lunt.

I will let you know guys.

Re: lunt 50 mod

Posted: Thu Jun 21, 2018 8:48 pm
by paulf
Hi, new to the forum and solar imaging! I’ve got Lunt LS50THA with B600. Just checking I understand this thread, if I had a 152mm refractor then it is possible to remove the objective and tube from LS50, screw directly into the refractor focuser, install an ERF, and then I’m good to go? Or would there be other upgrades needed, like moving to B1200.

Re: lunt 50 mod

Posted: Thu Jun 21, 2018 9:47 pm
by marktownley
Valery wrote: Wed Apr 12, 2017 8:20 pm The sweet spot size should be about the same as with a PST Mod-2. Both etalons are air-spaced and both have the same working diameter - 20mm. The only advantage is the possibility to move the CWL of the etalon to blue and red wings.


Valery
Very true Valery. I think I will give my lunt50 etalon unit on the back of the HaT, it should just screw on with the correct adaptor.

Re: lunt 50 mod

Posted: Fri Jun 22, 2018 3:01 am
by Valery
marktownley wrote: Thu Jun 21, 2018 9:47 pm
Valery wrote: Wed Apr 12, 2017 8:20 pm The sweet spot size should be about the same as with a PST Mod-2. Both etalons are air-spaced and both have the same working diameter - 20mm. The only advantage is the possibility to move the CWL of the etalon to blue and red wings.


Valery
Very true Valery. I think I will give my lunt50 etalon unit on the back of the HaT, it should just screw on with the correct adaptor.
Which etalon did you mean? LS50FHa? or from the LS50THa ?

Re: lunt 50 mod

Posted: Fri Jun 22, 2018 5:35 am
by marktownley
The pressure tuned module from the lunt50 telescope - use it in a collimated beam.

Re: lunt 50 mod

Posted: Fri Jun 29, 2018 3:09 pm
by DSobserver
paulf wrote: Thu Jun 21, 2018 8:48 pm Hi, new to the forum and solar imaging! I’ve got Lunt LS50THA with B600. Just checking I understand this thread, if I had a 152mm refractor then it is possible to remove the objective and tube from LS50, screw directly into the refractor focuser, install an ERF, and then I’m good to go? Or would there be other upgrades needed, like moving to B1200.
Basically yes but all depends on what scope you are talking about!
Larger bf would be better
Prefer coronado 10 or 15

Re: lunt 50 mod

Posted: Sun Jul 01, 2018 9:47 pm
by paulf
DSobserver wrote: Fri Jun 29, 2018 3:09 pm
paulf wrote: Thu Jun 21, 2018 8:48 pm Hi, new to the forum and solar imaging! I’ve got Lunt LS50THA with B600. Just checking I understand this thread, if I had a 152mm refractor then it is possible to remove the objective and tube from LS50, screw directly into the refractor focuser, install an ERF, and then I’m good to go? Or would there be other upgrades needed, like moving to B1200.
Basically yes but all depends on what scope you are talking about!
Larger bf would be better
Prefer coronado 10 or 15
Thanks for reply, don’t have a refractor as yet, but just thinking ahead.

Re: lunt 50 mod

Posted: Thu Jul 05, 2018 7:20 pm
by krakatoa1883
A very interesting discussion as I am also considering a LS50 mod. I have few questions if someone would be so kind to answer:

1. I assume the mod is fully reversible that is I can have back the original LS50, am I correct ?
2. Is the red cylinder with the PT knob simply screwed to the LS 50 white tube ? can they be separated easily ?
3. Which M68 adapter would I need for attaching the LS50 rear part to the telescope ? has this part a male or a female thread ?
4. I have seen in the above image a Coronado BF replacing the Lunt diagonal, is this replacement necessary ?

Thanks in advance

Re: lunt 50 mod

Posted: Tue Sep 04, 2018 10:35 am
by antonello
After a long time, during which no one knew if the Lunt 50 had a lens with a single lens or an achromatic lens, I discovered from this image
lunt 50.jpg
lunt 50.jpg (236.86 KiB) Viewed 5497 times

that even the Lunt 50, like the Lunt 60., seems to have a objective with single lens, and therefore the use of the Etalon of the Lunt 50, together with the two lenses of its collimator, used on a new telescope with an big achromatic objective, will not allow to obtain, in h-alpha, all the quality of the new big achromatic lens ... :(

Re: lunt 50 mod

Posted: Thu Feb 07, 2019 2:17 pm
by solarchatted
Hi
What an interesting discussion.
I am newbie on Solar and still deciding if to get a PST new [second hand is rare to find they go like cakes - obviously affordable!]
But I have been thinking to jump forward and get a Lunt 50 and then 'in the future - not now' possibly modify it to use on my AR152 988mm F/6.5.
What do you think - experts?

I am getting older and Solar would be an 'easy' addition for later years.

For now I am going to play a bit with White light only - just to get the hang of it again.

Thanks for your time

Re: lunt 50 mod

Posted: Fri Mar 01, 2019 5:58 pm
by GreatAttractor
antonello wrote: Tue Sep 04, 2018 10:35 am even the Lunt 50, like the Lunt 60., seems to have a objective with single lens
Hmm, interesting. Where does the image come from? I just double-checked my specimen (purchased in 2015) and it seems to have a doublet. I mean I didn't disassemble it, but it shows two upright minified reflections of my phone's LED when I hold it close, the same as my 90 mm achromat's objective.
But I have been thinking to jump forward and get a Lunt 50 and then 'in the future - not now' possibly modify it
Definitely! You will find some successful mods here on the forum. Mine are here and here.

Re: lunt 50 mod

Posted: Sat Mar 02, 2019 7:29 am
by antonello
Hello GreatAttractor
I found this image on internet...
It is not a photograph, is a drawing that can not solve the mystery.
It seems that only Lunt knows if the objective is single or achromatic :-)
The number of reflexes is not significant, even a single lens produces two reflections, like a glued doublet.
I still would like to know if the 60 lunt and the Lunt 50 have a single or achromatic lens.
You can easily solve the mystery without disassembling the lens by looking at a tree far away with your Lunt 50 without the etalon mounted. Can you do this? Thank

Re: lunt 50 mod

Posted: Sat Mar 02, 2019 8:46 am
by marktownley
Lunt50 is a doublet.

Re: lunt 50 mod

Posted: Sat Mar 02, 2019 10:35 am
by krakatoa1883
I disassembled my own for cleaning, it is a cemented doublet (front is positive, rear is negative).

Re: lunt 50 mod

Posted: Mon Mar 04, 2019 7:44 am
by antonello
Hello,
many thanks for the information.
Therefore the Lunt 50 Ha has an achromatic objective, and the image I posted was misleading. On the contrary, the lunt 60 Ha has a single lens
lens, as it is clearly written in this image
lunt_60.jpg
lunt_60.jpg (207.79 KiB) Viewed 5146 times
Some time ago I wanted to buy a Lunt 60 Ha to use it to see whole sun in Ha, and cannibalize it, using only the etalon group, on a large diameter achromatic. I did not buy it because I saw an image in which it seemed to have a objective with a single lens. I have then thought of buying a
Lunt 50 Ha, but I did not do it for the same reason.
I still wanted to get the same result and bought a Lunt 35 secondhand. I checked that this tool was little more than a toy and I worked to get something better.
With the Lunt 35 etalon I obtained a "Lunt-Zeiss 50", using a Zeiss achromatic lens 50 mm, f: 540 mm (teleminor) and two simple lenses from catalog for the collimator (-300 mm and +300 mm).
This is the result
lunt-zeiss_50.jpg
lunt-zeiss_50.jpg (117.73 KiB) Viewed 5146 times
The etalon group thus obtained can be placed on any telescope f: 10 approximately. I use it often on a Tal 100, when I want to see the protuberances in detail.
This is the instrument
lunt-tal_100.jpg
lunt-tal_100.jpg (265.21 KiB) Viewed 5146 times
I am very happy with the result.

Re: lunt 50 mod

Posted: Mon Mar 04, 2019 12:03 pm
by marktownley
That's a sweet setup!

Re: lunt 50 mod

Posted: Tue Mar 05, 2019 12:27 pm
by antonello
If it can interest someone ...
Here are the individual lens of 42 mm diameter f: -300 and f: +300 in my etalon Lunt 35.
lunt_35_mod.jpg
lunt_35_mod.jpg (284.28 KiB) Viewed 5125 times
Here is the simulation of the quality of this collimator with three different objectives.
Perfect lens 50/540
1_perfect_lens_50_540.jpg
1_perfect_lens_50_540.jpg (152.9 KiB) Viewed 5125 times
edmund50/500 achromatic lens
2_edmund_achromatic_50_500.jpg
2_edmund_achromatic_50_500.jpg (185.03 KiB) Viewed 5125 times
Single lens 50/500
3_single_lens_50_500.jpg
3_single_lens_50_500.jpg (167.53 KiB) Viewed 5125 times
We can do a reverse test.
Let's take the "telescope-optics.net" single lens Ha solar telescope, diameter 100 mm f:850 mm, with collimator for etalon,
https://www.telescope-optics.net/specia ... scopes.htm

This is the quality of this single lens telescope
4_lens_sistem_telescope_optics.jpg
4_lens_sistem_telescope_optics.jpg (161.42 KiB) Viewed 5125 times
If we now remove the single lens and put a perfect lens (apo or achro is similar), 100 mm f:1000 mm, we get a very bad quality
5_perfect_lens_100_1000_with_collimator_for_simgle_lens.jpg
5_perfect_lens_100_1000_with_collimator_for_simgle_lens.jpg (158.12 KiB) Viewed 5125 times

Re: lunt 50 mod

Posted: Tue Mar 05, 2019 10:11 pm
by marktownley
Interesting spot diagrams, thanks.