lunt 50 mod

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...
User avatar
krakatoa1883
Im an EXPERT!
Im an EXPERT!
Posts: 379
Joined: Sat Jun 11, 2016 9:41 am
Location: Mediolanum

Re: lunt 50 mod

Post by krakatoa1883 » Thu Jul 05, 2018 7:20 pm

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
Raf
My solar images and reports with articles on solar equipment

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Tue Mar 24, 2015 12:34 pm

Re: lunt 50 mod

Post by antonello » Tue Sep 04, 2018 10:35 am

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 506 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 ... :(

solarchatted
Oh, I get it now!
Oh, I get it now!
Posts: 21
Joined: Wed Mar 14, 2018 11:33 am
Location: Durham, UK
Contact:

Re: lunt 50 mod

Post by solarchatted » Thu Feb 07, 2019 2:17 pm

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
SolarChatted

User avatar
GreatAttractor
Almost There...
Almost There...
Posts: 592
Joined: Sat Jun 01, 2013 1:04 pm
Location: Poland/Germany

Re: lunt 50 mod

Post by GreatAttractor » Fri Mar 01, 2019 5:58 pm

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.
My software:
Stackistry — an open-source cross-platform image stacker
ImPPG — stack post-processing and animation alignment
My images

SW Mak-Cass 127, ATM Hα scope (D=90 mm, LS50 etalon), Lunt LS50THa, ATM SSM, ATM Newt 300/1500 mm, PGR Chameleon 3 mono (ICX445)

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Tue Mar 24, 2015 12:34 pm

Re: lunt 50 mod

Post by antonello » Sat Mar 02, 2019 7:29 am

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

User avatar
marktownley
Librarian
Librarian
Posts: 25028
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: lunt 50 mod

Post by marktownley » Sat Mar 02, 2019 8:46 am

Lunt50 is a doublet.
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
krakatoa1883
Im an EXPERT!
Im an EXPERT!
Posts: 379
Joined: Sat Jun 11, 2016 9:41 am
Location: Mediolanum

Re: lunt 50 mod

Post by krakatoa1883 » Sat Mar 02, 2019 10:35 am

I disassembled my own for cleaning, it is a cemented doublet (front is positive, rear is negative).
Raf
My solar images and reports with articles on solar equipment

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Tue Mar 24, 2015 12:34 pm

Re: lunt 50 mod

Post by antonello » Mon Mar 04, 2019 7:44 am

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 155 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 155 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 155 times
I am very happy with the result.

User avatar
marktownley
Librarian
Librarian
Posts: 25028
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: lunt 50 mod

Post by marktownley » Mon Mar 04, 2019 12:03 pm

That's a sweet setup!
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!

antonello
Ohhhhhh My!
Ohhhhhh My!
Posts: 71
Joined: Tue Mar 24, 2015 12:34 pm

Re: lunt 50 mod

Post by antonello » Tue Mar 05, 2019 12:27 pm

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 134 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 134 times
edmund50/500 achromatic lens
2_edmund_achromatic_50_500.jpg
2_edmund_achromatic_50_500.jpg (185.03 KiB) Viewed 134 times
Single lens 50/500
3_single_lens_50_500.jpg
3_single_lens_50_500.jpg (167.53 KiB) Viewed 134 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 134 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 134 times

User avatar
marktownley
Librarian
Librarian
Posts: 25028
Joined: Tue Oct 18, 2011 5:27 pm
Location: Brierley Hills, UK
Contact:

Re: lunt 50 mod

Post by marktownley » Tue Mar 05, 2019 10:11 pm

Interesting spot diagrams, thanks.
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!

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests