Massive improvements to the PST

[Poita (Peter)]

Originally Posted by brian nordstrom

Peter If you can get me the dimentions and drawings for both I will have a go at machining up an adaptor , it will have to be after mid june before I get a go at this , as we , up here in Darwin are full on doing a major shut down at the local DLNG plant , yours wil be the first free adaptor .
Just need measurements .
Jpeg is alright .
Brian.

That is very kind. Would it be better if I sent you the unused parts that have the thread on them? I don't want to mess it up!

[h0ughy (David)]

Originally Posted by Poita

If someone would make a simple PST thread to SCT thread adapter, they would have a real winner on their hands.

All thanks for these experiments really have to go to Merlin and his wonderful PST help over the years.

More pics attached:

I can see what you mean - there would have to be some talented soles that could make the adapter, man it would give a whole lease of new life to the poor old pst. I had two over the years, and gave them up because i couldnt image with them or get a clear view without ghosting - this virtually eliminates that

[Poita (Peter)]

Originally Posted by h0ughy

I can see what you mean - there would have to be some talented soles that could make the adapter, man it would give a whole lease of new life to the poor old pst. I had two over the years, and gave them up because i couldnt image with them or get a clear view without ghosting - this virtually eliminates that

Absolutely zero ghosting, and very sharp. I'm really happy with it, now to find some rings...

[Wodnas (Robert)]

This is my amateur attempt to mount my PST. I used a cheap scope that has GOTO and made an adaptor to hold the PST. Set the tracking for solar and away you go. Complete scope including mount was $135 plus freight. Not high tech like some here but works for me.





Cheers Bob

[Poita (Peter)]

I've had a few more questions, some quick answers:

Q: What pieces did you use on the camera/eyepiece end to hold the BF?

The easiest way to do this is to use a celestron 1.25" diagonal. The blocking filter unscrews from the 'black box' and is the same thread as the Celestron eyepiece holder part of the diagonal. Unscrew the celestron eyepiece holder and screw the Blocking Filter/Eyepiece holder from the PST onto the Celestron diagonal.

Q: Any quick tips on imaging with a QHY5 or similar mono camera? e.g. will I need a barlow?

With the standard PST (the model I had anyway) the eyepiece holder was in two pieces, one piece was an empty (small) extension tube the same size as the eyepiece holder that included the BF.
For images I had to unscrew the eyepiece holder and extension tube, remove the empty extension tube and screw the eyepiece holder straight into the PST black box.

For the modified PST with the GSO focuser, I had to add an extension tube to bring it to focus. I used a barlow with the lens removed from and it just got me there.

[Marke (Mark)]

If you need an adapters or fittings rty these guys , they can make up just about anything and have great service.
http://www.preciseparts.com/ppmain/adapterf.html

[Merlin66 (Ken)]

There's a couple of good suppliers in Europe who now supply adaptors for the front and rear threads (M50 x 1) of the PST etalon.
http://www.aokswiss.ch/index_sonne.html
http://www.teleskop-austria.at/shop/...dap-pst-508-hu
The pentaprism/ focus arrangement in the original PST is marginal. An out of alignment pentaprism can cause real headaches with astigmatism. Dump it as soon as you can!
As Peter mentioned: the eyepiece holder on the Black Box comes in two versions, both use two sections....
The section nearest the Black box can be empty (just a spacer) on the original "gold" objective models - this can easily be removed to increase the available back focus.
On the later "blue" objective PST's Coronado added a small "mini-erf" to the front of this tube to reduce the energy loading on the more sensitive blocking filter.
For imaging, this can be safely removed.....
The tube section, where the eyepiece goes, contains the small (5mm diameter) blocking filter. This is a CRITICAL component in the Ha filter system.
Hope this helps.

[trent_julie]

Hey all,
I started my Nervous PST Mod tonight, I should be able to post comparison photos tomorrow weather permitting.