Telescope mod ?

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Robin
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Telescope mod ?

Post by Robin »

I have had the offer of a SW Traverstar 80mm scope, is this any good for a PST mod 1, what parts would I need to complete the job
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Re: Telescope mod ?

Post by swisswalter »

Hi Robin

any datas like FL, optics and so ?


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

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Re: Telescope mod ?

Post by Robin »

Hi

80mm - 400mm - F5

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Re: Telescope mod ?

Post by swisswalter »

Hi robin

Ah very short. You need to change the front and back lenses of the PST etalon set up as it is :unsure:


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
peter drew

Re: Telescope mod ?

Post by peter drew »

Robin. You have to use a donor of at least F10 for a standard PST mod, a modded 80mm F5 would result in an effective 40mm aperture, the same as the original PST. As Swisswalter says, you would have to modify the optics of the PST etalon to gain any benefit. :)


colmic

Re: Telescope mod ?

Post by colmic »

Hi,

i don't completely agree.

I made many PST mods since 2005 :
- Tak Sky90 (F/5) + 70 ERF (so a little diaphragm) + Extender 1.6x + PST Etalon + BF5 => worked very well
- Tak FS60 (F/6) + 70 ERF + Glasspath Baader 1,7x + PST Etalon + BF10 + Bino Baader => works perfectly
- Tak TOA130 (F/7.7) + 135 ERF + Glasspath Baader 1.25x + PST Etalon + BF10 => see my photos on Solarchat
- some refractor for friends like Televue Genesis F/5 + TV 2x Barlow and other short tubes.

In fact, we have the choice :
- stay at F/10 with best results
- use a Barlow just in front of PST Etalon (with it's original lenses of course), and calculate the Barlow to approach F/10. The placement of the Barlow in front of Etalon is important so.

Results between natural F/10 or Barlow'ed F/10 are very comparable.

Of course, it's just my opinion and it is discutable, but in my experience i prefer to use a short tube + Barlow, it's more versatile, transportable...

Adding : i tested on my TOA130 with and without 1.25x Glasspath and i clearly saw the difference in resolution. Without the Barlow the refractor is diaphragmed by the 20mm diameter of the PST Etalon, so it works at 100mm diameter (1000mm focal). With the Barlow i see the difference between 100mm and 130mm in resolution. So the same results with my Tak FS60, i clearly see the difference between 60mm and 40mm in resolution.

So you can test with a 2x Barlow just in front of PST Etalon on your 80/400 and see results.


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Re: Telescope mod ?

Post by swisswalter »

Hi Michel

Thank you very much, that is a very interesting comment. I have to try that with the glasspath adapter


Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)
peter drew

Re: Telescope mod ?

Post by peter drew »

Hello Michel, I was careful to qualify my comment by saying "standard" PST mod, the F10 requirement for this is still taking time to be common knowledge amongst those new to the process. My first mod was a Sky90 and although it worked very well I didn't realise at the time that it was being vignetted to a smaller aperture. Your experience with Barlow lenses prior to the internal etalon is most interesting as it would be much more convenient to use faster systems, my 150 F10 mod is as much as I would wish to operate. A diagram of your layout would be much appreciated. :bow:


colmic

Re: Telescope mod ?

Post by colmic »

Here is a photo of my TOA130 PST setup :



You can see :
Baader D-ERF135 in front
2 inch adapter in prime focus with Glasspath 1.25 inside
PST Etalon with an adapter T2
T2 tube
BF10
Grasshopper3 camera

Here is some of my best images taken with this setup :












I will make another photo of my FS60 PST setup with bino tomorrow...


Bill E.

Re: Telescope mod ?

Post by Bill E. »

Michel, your mod looks easy to make and install .I want to do something similar. Could you show us a close up of your mod? also Do you have a disassembled picture of mod?
Thanks, Bill


colmic

Re: Telescope mod ?

Post by colmic »

Hi Bill,

here are 2 photos, i hope all is clearly visible.

First, my other PST mod, with the Tak FS60 on the Vixen Porta:



The Baader C-ERF 70 is inside the dewcap, in front of the objective.
You can see all the pieces with the Bino

Other photo with all disassembled :



You can see, in order of the optical way:
- M43-T2 adaptor for the Tak
- the Baader 1.7x Glasspath (Glasspath are made for bino but works very well with PST mod). Note that i use a 1.7x for the FS60 and a 1.25x for the TOA130 to have about F/10 just in front of the PST Etalon.
- the PST etalon with 2 adaptors T2, T2-M50 for the entrance, and i don't remember for the other side !
- an extension tube T2
- the Baader clic-lock eyepiece clamp for the BF10
- the Coronado BF10 filter
- an adpator for the bino Baader
- a 2.6x Baader Glasspath to fill the eyepiece field ! (all the sun with proms is visible)
- the Baader Mark V bino with 2 TV 32mm Plössl

For imaging i use the same setup but i put a 1.8x TV Barlow just after the BF10

Is all clear ?


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Re: Telescope mod ?

Post by Merlin66 »

Michel,
Using a standard PST etalon assembly, I find the issue with using a barlow to increase the f ratio is still being able to achieve the majic 200mm spacing inside the prime focus....


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Re: Telescope mod ?

Post by Robin »

Hey up Guys, my post has got far too technical for me. All I want to know is what I need or a simple mod to my PST using the black bit and just replacing the OTA , I have learned, I think that I need a f10 scope, ok but what else, and where to buy the parts. I am a dummy when it comes to solar , DSO imaging is easy compared with this.


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Re: Telescope mod ?

Post by solarchat »

please keep all this stuff in the mod section of this forum.


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Re: Telescope mod ?

Post by Allcart »

For the stage 1 mod, all you need is a donor scope, ERF, and a nosepiece for the etalon.
Merlin66 has a pdf with all the info and more. He may send it to you if he can.


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Re: Telescope mod ?

Post by Merlin66 »

Robin, et al,
If you want a copy of the PST mod document, just drop me an email...
kenm(dot)harrison(at)gmail(dot)com


"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.io/g/astronomicalspectroscopy  
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
colmic

Re: Telescope mod ?

Post by colmic »

Robin,

many methods here (sorry in french but images are simple to understand) :

http://www.astrosurf.com/jiaifer/modificationpst.htm
http://www.webastro.net/forum/showthread.php?t=64545


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Re: Telescope mod ?

Post by Robin »

Thanks chaps, Email sent Ken
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Re: Telescope mod ?

Post by rbotero »

Great stuff Michel! I have most parts already from using a MKIV for WL with my AP152 at f/7.5. I only need to get an ERF and a PST etalon....;)

Thanks for sharing.

Roberto


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Re: Telescope mod ?

Post by SolarJohn »

quote
If you want a copy of the PST mod document, just drop me an email...
kenm(dot)harrison(at)gmail(dot)com

Why is this document not in the Solar Reference library online?

SolarJohn


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Re: Telescope mod ?

Post by Merlin66 »

SolarJohn,
When I started to do PST mods back in 2007 I was put under a lot of "pressure" to stop advocating such a mod to a critical sophisticated safety related optical assembly.
I therefore elected to control the distribution of the document and issued it freely upon request. That way I knew who was likely to be doing the mod and could offer 24/7 support to ensure success.
Times change, and now the PST mod is well accepted and almost "main-stream".
I'm working on an update to the document and will reconsider issuing to a wider audience.


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"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: Telescope mod ?

Post by solarchat »

Im assuming that this is sort of the mainstream headquarters for PST modding now. I had no intention of it being this way but it just kind of came together. I dont understand the big deal in sharing this knowledge. I would never attempt any of this mod stuff because thats just not my thing, outreach is what I do first and foremost. Im also a big advocate of supporting the existing professional solar scope modders...ie Lunt Solar Systems and other vendors- in any way possible to keep the advancement coming.
ANyway, although I have no interest in it, I am glad to provide a home for it as long as the finances last.


Stephen W. Ramsden
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Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org
colinsk

Re: Telescope mod ?

Post by colinsk »

SolarJohn,
When I started to do PST mods back in 2007 I was put under a lot of "pressure" to stop advocating such a mod to a critical sophisticated safety related optical assembly.
I therefore elected to control the distribution of the document and issued it freely upon request. That way I knew who was likely to be doing the mod and could offer 24/7 support to ensure success.
Times change, and now the PST mod is well accepted and almost "main-stream".
I'm working on an update to the document and will reconsider issuing to a wider audience.

If you would like to bounce it off another person I would love to edit and provide comments for you. Your safety document and the PST document are a great resource that have helped me immeasurably.

colink at designerinlight dot com


colinsk

Re: Telescope mod ?

Post by colinsk »

Im assuming that this is sort of the mainstream headquarters for PST modding now. I had no intention of it being this way but it just kind of came together. I dont understand the big deal in sharing this knowledge. I would never attempt any of this mod stuff because thats just not my thing, outreach is what I do first and foremost. Im also a big advocate of supporting the existing professional solar scope modders...ie Lunt Solar Systems and other vendors- in any way possible to keep the advancement coming.
ANyway, although I have no interest in it, I am glad to provide a home for it as long as the finances last.

My only solar interest is in telescope design even though I do like to look. This has been the haven. Thank you. :rockon:


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