PST mod Telescope question.

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aboy
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PST mod Telescope question.

Post by aboy »

I there.

I just have a silly question here.

For a PST mod I know it's better a F/10 refractor scope. But, I was reading about the lunt 100 specifications and I find out that is like the Explorer Scientific 102.

My question here is:

It is possible to use the ES 102 on the PST modification as well?

Here are the specifications on both scopes:

Code: Select all

LS100THa scope Specifications (Single Stack)

Optical Aperture: 102 mm
Etalon: Internal <0.7 Angstrom
Tuning: Internal Pressure Tune (Doppler True Tuning)
Focal Length: 714 mm
F Ratio: F/7
Focuser: 2″ Feather-Touch focuser with 10:1 reduction
Tube diameter: 121 mm
Tube length with blocking filter: 634 mm
Storage: Aluminum finished hard case with fitted foam
Weight: 12.2 lb

Code: Select all

ES-ED102mm Essential Series Aluminum Air-Spaced Triplet Refractor
Item Number	ES-ED10207-01
Optical Aperture: 102 mm
Focal Length	714mm
Focal Ratio	f/7
Limiting
Magnitude	12.5
Resolution	1.14 arcsec
Tube Length
w/ Dew Shield	30.5"; 774mm
Tube Length
w/out Dew Shield	23.75"; 603mm
Diameter	119mm
Weight	9.6 lb; 4.4 kg
Thanks for all your time guys.


"I'm enough of an artist to draw freely on my imagination. Imagination is more important than knowledge. Knowledge is limited; imagination encircles the world."

--Albert Einstein, October 26, 1929
------------------------------------------------------------

EQ:

Double stack 60mm Coronado ( pre-meade ) H-alpha filters with a 15 blocking filter.

DMK 51AU02 the imaging source Mono CCD camera.

Orion Short 2x Barlow.

Explore Scientific 102mm f/7 Air-Spaced Triplet ED Apochromatic Refractor Telescope.

Astrotelescope ( Planet Killer ) 102mm f/11 hand corrected doublet. Refractor Telescope.

Losmandy - G11 ( Gemini 1 )

FireCapture, AutoStakkert 2, PixInsight, Registack 6 and Photoshop CS 6.
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Re: PST mod Telescope question.

Post by Merlin66 »

You could use the 102/714 with the PST Mod, but it would be restricted to an effective aperture of 71mm (714/10).
Alternatively you could replace the front barlow element of the PST assembly with a -140mm barlow to give the full 102mm.


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aboy
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Re: PST mod Telescope question.

Post by aboy »

Merlin66 wrote:You could use the 102/714 with the PST Mod, but it would be restricted to an effective aperture of 71mm (714/10).
Alternatively you could replace the front barlow element of the PST assembly with a -140mm barlow to give the full 102mm.

How I can replace the Barlow ?


"I'm enough of an artist to draw freely on my imagination. Imagination is more important than knowledge. Knowledge is limited; imagination encircles the world."

--Albert Einstein, October 26, 1929
------------------------------------------------------------

EQ:

Double stack 60mm Coronado ( pre-meade ) H-alpha filters with a 15 blocking filter.

DMK 51AU02 the imaging source Mono CCD camera.

Orion Short 2x Barlow.

Explore Scientific 102mm f/7 Air-Spaced Triplet ED Apochromatic Refractor Telescope.

Astrotelescope ( Planet Killer ) 102mm f/11 hand corrected doublet. Refractor Telescope.

Losmandy - G11 ( Gemini 1 )

FireCapture, AutoStakkert 2, PixInsight, Registack 6 and Photoshop CS 6.
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Re: PST mod Telescope question.

Post by Merlin66 »

The front barlow lens of the PST assembly can be easily removed and replaced with a 25mm -140mm barlow - if you can find one from Thorlabs/ Edmund Optics.


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https://groups.io/g/astronomicalspectroscopy  
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: PST mod Telescope question.

Post by Valery »

Merlin66 wrote:The front barlow lens of the PST assembly can be easily removed and replaced with a 25mm -140mm barlow - if you can find one from Thorlabs/ Edmund Optics.

It can't work as designed in the PST or close. Two lenses - barlow negative and a second positive (refocusing objective) works as a whole system and they
have no spherical aberration, no coma and astigmatism. If one change one lens with unknown radii, then absolutely no warranty that these aberrations will be fixed in a new system. More so, we can state, that they will not be fixed.

Better to change F/7 cone to F/10 with regular Barlow lens or with a special barlow lens. The PST etalon block better be work with it's native lens system.


Valery.


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Re: PST mod Telescope question.

Post by Merlin66 »

Valery,
I hear you, but many amateurs have already successfully changed the front barlow element in PST mods.


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https://groups.io/g/astronomicalspectroscopy  
http://astronomicalspectroscopy.com
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer
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Re: PST mod Telescope question.

Post by Valery »

Merlin66 wrote:Valery,
I hear you, but many amateurs have already successfully changed the front barlow element in PST mods.
But I never saw crystal clear razor sharp images taken with PST etalon with randomly chosen lenses.
So, the "success", I suspect, is limited.


Valery.


"Solar H alpha activity is the most dynamic and compelling thing you can see in a telescope, so spend accordingly." (c) Bob Yoesle.

Largest full size 185 - 356mm Dielectric Energy Rejection Filters (D-ERF) by ARIES Instruments.
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Re: PST mod Telescope question.

Post by aboy »

Well. Thank you guys for all the answers.


"I'm enough of an artist to draw freely on my imagination. Imagination is more important than knowledge. Knowledge is limited; imagination encircles the world."

--Albert Einstein, October 26, 1929
------------------------------------------------------------

EQ:

Double stack 60mm Coronado ( pre-meade ) H-alpha filters with a 15 blocking filter.

DMK 51AU02 the imaging source Mono CCD camera.

Orion Short 2x Barlow.

Explore Scientific 102mm f/7 Air-Spaced Triplet ED Apochromatic Refractor Telescope.

Astrotelescope ( Planet Killer ) 102mm f/11 hand corrected doublet. Refractor Telescope.

Losmandy - G11 ( Gemini 1 )

FireCapture, AutoStakkert 2, PixInsight, Registack 6 and Photoshop CS 6.
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Re: PST mod Telescope question.

Post by marktownley »

It's all about compromises this modding; unless you're using bespoke designed optics for a project there will always be a price to pay in terms of image quality. I modded a 70mm f6 refractor to use with a PST mod, I was pleased with the results. At the end of the day it's a way of getting a result without spending big bucks.


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Re: PST mod Telescope question.

Post by aboy »

marktownley wrote:It's all about compromises this modding; unless you're using bespoke designed optics for a project there will always be a price to pay in terms of image quality. I modded a 70mm f6 refractor to use with a PST mod, I was pleased with the results. At the end of the day it's a way of getting a result without spending big bucks.
Well, Like you say.

I do want the mod for HD pictures, and I hear you guys that my Astrotelescope 102 f/11 will do the job. But, I always was wonder if I can get the ES102ED Working for this mod as well.

Thanks you guys for your the answers.


"I'm enough of an artist to draw freely on my imagination. Imagination is more important than knowledge. Knowledge is limited; imagination encircles the world."

--Albert Einstein, October 26, 1929
------------------------------------------------------------

EQ:

Double stack 60mm Coronado ( pre-meade ) H-alpha filters with a 15 blocking filter.

DMK 51AU02 the imaging source Mono CCD camera.

Orion Short 2x Barlow.

Explore Scientific 102mm f/7 Air-Spaced Triplet ED Apochromatic Refractor Telescope.

Astrotelescope ( Planet Killer ) 102mm f/11 hand corrected doublet. Refractor Telescope.

Losmandy - G11 ( Gemini 1 )

FireCapture, AutoStakkert 2, PixInsight, Registack 6 and Photoshop CS 6.
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