Conversion kit PST40 mod 2

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Conversion kit PST40 mod 2

Post by Bastelhannes »

Hi folks,

before i am going to make a big mistake in this lovely board: is ist allowed to present our new conversion kit for PST40 mod2? I have developed a long time and we started production...

If anyone could let me know, please...

Karsten


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Re: Conversion kit PST40 mod 2

Post by Montana »

Sure thing, there are only a few rules here NO POLITICS // NO RELIGION // NO ARGUMENTS // NO OVERINFLATED EGOS

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If you aren't breaking these then you are good to go :)

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Re: Conversion kit PST40 mod 2

Post by Sol seeker uk »

Bastelhannes wrote: Mon May 09, 2022 11:53 am Hi folks,

before i am going to make a big mistake in this lovely board: is ist allowed to present our new conversion kit for PST40 mod2? I have developed a long time and we started production...

If anyone could let me know, please...

Karsten
Hi Karsten, what's in the kit please as I'm about to do mine


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Re: Conversion kit PST40 mod 2

Post by Bastelhannes »

Okay, here we go... (this posting has only one religion included: the sun cult...)


Conversion kit MEADE CORONADO PST40 Mod2 with DERF110

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An important remark in advance:

For legal reasons, we cannot accept any liability for the conversion kit offered here.

This is because we have no influence on the basic components like DERF and the PST40. Both manufacturers guarantee safe handling. However, the PST40 is disassembled, so the liability at that moment is not applicable.

Logically, we also have no influence on the fact that you really set up the whole thing correctly. It's easy, but we still can't assume liability.

Solar observation is dangerous, so please approach it with due respect.

For the conversion you need patience for one step: the etalon has to be detached from the black base body of the PST40. This is a bit tricky, but doable. We include instructions for this.







How does the conversion kit work?

An existing or new telescope is used as the new main optic. We recommend refractors, a Fraunhofer refractor is completely sufficient, because we observe only in one wavelength.

Before buying a refractor with 200 mm aperture: the air turbulence during the day due to the sun allows high resolutions for a short time, but based on our own experience we do not like to go beyond 120 mm aperture. 

The refractors usually have to be shortened by about 80 mm, because the etalon 200 mm has to be in front of the primary focus of the telescope on the objective side. This can be done easily with patience and a hacksaw. But we can also offer this. Lovingly, the tube is then shortened using a chop saw.

The Coronado PST is disassembled: Etalon and ITF/block filter are needed for the conversion kit. 





The conversion kit contains the following components


  • DERF low-energy filter from Baader-Planetarium, diameter 110 mm
    3D printed DERF holder (we need the diameter of the exchange cap when ordering)
    Adapter 2" to Etalon
    Adapter Etalon to TS-Optics Heli2 OAZ
    Focuser TS Heli2
    Adapter TS Heli2 to ITF & block filter of PST40
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The backfocus was defined with 55 mm to be able to use DSLR as well.




Here the setup on the eyepiece side in detail.



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Link to the product (different sets are available, just drop me a note...):

https://www.teleskop-spezialisten.de/sh ... anguage=en


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Re: Conversion kit PST40 mod 2

Post by Sol seeker uk »

Thanks Karsten, so this is still a stage 1 mod as you keep the 5mm blocking filter that's in the original PST? I think I've read that 5mm is good up to 500mm focal length, 10mm up to 1080mm and 15mm up to 1500mm.. I'm sure that the new tube in the donar scope has a longer focal length than 500mm in the picture?
The 110mm D-ERF looks to be reduced because of the housing, if so how much by?
So from the camera sensor to the etalon, that's 200mm inside the focus point of the scope?


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Re: Conversion kit PST40 mod 2

Post by Bastelhannes »

Hi Sol Seeker,
Thank you for your questions.

As far as i understood, a Mod2 conversion means to get rid of the black box. Of course you can replace the BF5 by a BF10, but then we talk about 1000€ plus. Also I am not sure, if it is really an advantage to use a BF10 or BF15, because the sweet spot would stay the same.

The DERF110 is reduced by 4 mm in diameter. If you have any idea how to mount to DERF without reducing the optical diameter I am very curious. This would give me new opportunities. I found no safe way to keep the whole 110 mm available for the optical path.

I do not understand the last question, but maybe I can give you some details: The etalon is 200 in front of the primary focus of the telescope. The rest of the optical h-alpha Mod2 train is designed to get the focus of the rear lens of the etalon at sensor plane. This approximately 200 mm.
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Re: Conversion kit PST40 mod 2

Post by Sol seeker uk »

Sorry to ask questions, I'm really new to solar, some parts I understand but other parts I find confusing and don't want to make a costly mistake
So you don't think the pst needs more that a bf5 even if the donar scope has more than a 500mm focal length?
Lots of people do stage 2 mods where they change the blocking filter for a larger one, sure you can then do away with the black box( penta prism) but there must be a reason for a bf10-bf15.. I understand the sweet-spot is to do with the tuning of the etalon and as Marty has said the sweet-spot gets smaller when using a bigger focal length donar scope
The reason I asked about the D-ERF is that in the image it doesn't look like there's 100mm of clear aperture , so thought you had reduced the aperture for a reason( again I've read some do this quite intentionally especially in calcium K)
So do you have stock of the components or do you order them as and when you get a sale?


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Re: Conversion kit PST40 mod 2

Post by Bastelhannes »

Please ask questions. You are not the first one thinking about these problems.

BF5: I only chose it, because it is in the PST40 already. Of course I would like to use a BF10. If you have 1000€ more to spend: go ahead, buy it. I do not have this money. So i got stuck to the BF5 and its limiting field of view.

D-ERF: Her wwe ahave another problem: there is not 120 mm aperture DERF available. Only 90 mm, 115 mm and 135 (180 and 75 as well). So i choose the DERF 110, because the price difference to DERF135 is huge (110 mm = EUR 525, 135 mm = €845).

My conversion is a balance of price and effort...


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Re: Conversion kit PST40 mod 2

Post by Bastelhannes »

Ah, I forgot the answer:

The adapters are all on stock, the DERF holder will be printed on demand, because it's dimensions depend on the scope and DERF. The DERF will be ordered on demand.

We do have a bunch of scopes on stock, only PST40 need to be ordered, if you do not have any.


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