Pst tube being a swine

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Sol seeker uk
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Pst tube being a swine

Post by Sol seeker uk »

hi all, I'm starting to get the confidence up to mod my PST, still not 100% understanding it but I'm going to give it a go.. first hurdle is the gold tube.. take it's a normal thread on it, it's not left handed is it? I'm trying it with the box on the left of me tube on the right and with a boa strap and some duct tape for grip I still can't get it apart... I've read about heating it up but I feel I'd melt the plastic where it meets the tube...don't really want to cut the tube if I can help it
While I'm here, when using it natively as a PST all the tuning is over to the left, to the right it just whites out, even looking for proms it's still over to the left, is that normal?
I'm going to mod a Tal 100rs, do I need a D-ERF, or could I get away with just a 35nm ha filter? If I need the D-ERF, should I mount it on the tube or on the dew shield?
Brace yourselves for 3 million questions :bow2


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Re: Pst tube being a swine

Post by marktownley »

Hi there 😊

Pst tube is normal thread so unscrew like a bottle top. If you're struggling use a boa constrictor strap to undo it.

Tal is a great scope for a Pst mod, mount the sub erf on one of the scope baffles internally, it will be fine.

Mark


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Re: Pst tube being a swine

Post by Sol seeker uk »

Thanks mark, that was trying with the boa and the PST in a vice.. I give it another try, just incase I was turning the wrong way
ERF on a baffle... That sounds like it could save me money .. do you mean the 2 inch baader 35nm on the baffle or a D-ERF?
Any ideas on the tuning?


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Re: Pst tube being a swine

Post by Rusted »

Like you, I struggled to dismantle my PST.
Once committed to dismantling I could not give up.

I used G-cramps [C-clamps] to hold the black body to the workbench. [Prism removed]
Then used a pipe as a lever to help the Boa.
I came very close to breaking the Boa strap.
There was a loud crack as the thread locker finally broke free.
Even then I had to keep working hard to unscrew the gold tube little by little.
This is one of several blog posts at the time of my struggles:

https://fullerscopes.blogspot.com/2018 ... strap.html

Click on Newer Posts and Older posts to reach the whole series.
My own experiences might be useful.


http://fullerscopes.blogspot.dk/

H-alpha: Baader 160mm D-ERF, iStar 150/10 H-alpha objective, 2" Baader 35nm H-a, 2" Beloptik KG3,
Lunt 60MT etalon, Lunt B1200S2 BF, Assorted T-S GPCs or 2x "Shorty" Barlow, ZWO ASI174.
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Re: Pst tube being a swine

Post by Sol seeker uk »

Thanks, this is the removal of the gold tube, does that mean I'm in for more fun with the removal of the ep holder.... Oh great... Hopefully they run out of loctite on the tube, certainly feels like it welded on


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Re: Pst tube being a swine

Post by MalVeauX »

Hi,

Heat is your friend. Use a hair dryer or similar. It won't melt anything. But it will heat it up to the point of expanding just enough to wax and wane any adhesive/glue to make it easier to unthread. Heat it up real good, then give it a good wrench strap turn (wear gloves, its hot). Then let it cool down and try to use the wrench strap again. Keep up this process, hot and cold. It will come undone without any markings.

If you don't care about marking the tube, just use channel locks and it will come undone no problem if you're ok with teeth marks.

Very best,


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Re: Pst tube being a swine

Post by Sol seeker uk »

Quick update, I've managed to unscrew it but it's unscrewed from the black box end, don't suppose it's a bad thing but it was the tube I was looking to get off first


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Re: Pst tube being a swine

Post by marktownley »

Sol seeker uk wrote: Mon Apr 18, 2022 2:54 pm Quick update, I've managed to unscrew it but it's unscrewed from the black box end, don't suppose it's a bad thing but it was the tube I was looking to get off first
Hi Derek

You need to take the rubber knurled ring off the etalon and the metal tuning sleeve to remove etalon from the tube else you will pop the etalon if you use a boa on the rubber ring.

Mark


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Re: Pst tube being a swine

Post by Sol seeker uk »

Is this the part where under the knurled ring theres a sticker saying do not remove, under this is the screw to remove first?
This is what I've read, not done it yet


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Re: Pst tube being a swine

Post by marktownley »

Sol seeker uk wrote: Tue Apr 19, 2022 6:02 pm Is this the part where under the knurled ring theres a sticker saying do not remove, under this is the screw to remove first?
This is what I've read, not done it yet
You got it! :)


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Re: Pst tube being a swine

Post by FRAZ »

I don't know if you got this done or not but my first PST mod, I just cut the gold tube and used it as a nosepiece.


Stage 2 mod completed @ 100, 127.
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Re: Pst tube being a swine

Post by Sol seeker uk »

FRAZ wrote: Sat May 07, 2022 5:50 pm I don't know if you got this done or not but my first PST mod, I just cut the gold tube and used it as a nosepiece.
Thanks FRAZ, I'm going to try not to cut the tube, I want to test the etalon first before I do anything.. I've held off ordering the blocking filter and the D-ERF until I'm confident on the etalon otherwise its the biggest weak link.... Tomorrow looks like a decent test day then I know if I'm wasting my time with it or not.. fairly hopeful thou


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