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Author Topic: PST Extension Tube Removal  (Read 20439 times)

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Offline NickH

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Re: PST Extension Tube Removal
« Reply #15 on: 06:35:19, 04 June, 2006 »
Guys...I canot check yet as I am in Japan for the week (looking at the Sun right now out of the hotel window with the PST CaK)

WIll check when I get back. Ian did mail me saying he could not get focus at all with the EOS with the spacer in place, and when removed the EOS only saw a bright yellow disc, indicating a blocking filter.

ho hum. :-(



Celestron C11: DSI-C/Toucam Pro 2 ICX mod and SC1.5 mod/ Meade LPI/EOS300D/ED80/WO80ZS/Shoestring guider. PST/PST CaK/ART285

No time....always bloomin cloudy...need to build the Obsy..

Offline AndyJones

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Re: PST Extension Tube Removal
« Reply #16 on: 17:00:15, 09 June, 2006 »
Afternoon all,

Just thought i'd share some of the pictures i took when i took my PST extension tube off....

If only i could take some decent photo's with it  :( All i seem to do is end up with pictures with loads of macropixels and the odd dark sunspot (using a Canon 350D and 2x barlow) or i can't get my webcam to come to focus (it looks like it needs to go in even further than having the extension tube removed. Does anybody know of any good guides of Solar photgraphy with a PST???

Anyway, enjoy the pics....

Andrew J.




[attachment deleted by admin]

[attachment deleted by admin]
Tal-2M, Skywatcher StarTravel 120, WO ZS66 APO, Coronado PST, EQ3-2, Canon 10D, Phillips ToUCam Pro + MOD.

Offline synner

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Re: PST Extension Tube Removal
« Reply #17 on: 19:16:32, 09 June, 2006 »
Cor! That really was glued in tight weren't it! :shock:

No wonder I couldn't get it out :roll:
Nick
synner.co.uk

My ethical unpredictability is by default proof of its hard won vitalty

Offline chunkster

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Re: PST Extension Tube Removal
« Reply #18 on: 16:13:02, 19 June, 2006 »
LOL !!  just done my PST !!  very similar method to yours ...
Rev Dob 12"
William Optics ZS 80 + binoveiwers
PST (modded)
Toucam 2
Distinct lack of ability ... ?

Offline ChrisLX200

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Re: PST Extension Tube Removal
« Reply #19 on: 16:49:13, 19 June, 2006 »
If it were me, I'd try a bit of heat with a blowtorch first - no, I don't mean get the thing red hot! just heat the extention tube to about 120deg. That won't do any damage to internal components - just be careful to keep the heat played on the outside of the extention tube (don't poke the flame down the hole!). Do it quickly and use a glove or a rag and unscrew it when it's hot... Depends a bit what they used to lock the threads - some hold up to 300deg C which is probably not safely attainable. Gotta be worth a shot rather than brute force approach :)

If that didn't work, and you don't want to keep the extension tube, drill a 5/16" right through it and use a steel dowel rod.

Bl**dy mole grips! - that and a lump hammer was most of my car repair kit when I were a lad :)
Chris Heapy - current: 10-Micron GM2000HPS-II U/P, G11/Gemini, TV NP127is, Altair 8" RC, TV Genesis SDF, TV Pronto, SW Equinox 80ED, 10" LX200, 12" f/5.4 Newt, Vixen 90mm.
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Offline Dogman

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Re: PST Extension Tube Removal
« Reply #20 on: 18:01:35, 19 June, 2006 »
If you use two bits of wood in the jaws of the vice and rubber around the tube it should come off with no damage - I've just done three - two Ha and one CaK - but the CaK has a filter in it :-( and they came out remarkably easily

Cheers
Dunc

Meade LX200 12" Classic, ED80 Pro, PST Ha and PST CaK
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Offline number26

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Re: PST Extension Tube Removal
« Reply #21 on: 19:20:47, 21 June, 2006 »
Managed to take the extension tube off and it has the 'new filter' in it. Has anyone determined what this is yet?  ???

Mark
Mark

LXD75 6N, Revelation 80, a VERY old C8, Coronado PST, NexImage, Canon 20D

Offline Kieron

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Re: PST Extension Tube Removal
« Reply #22 on: 12:37:13, 27 June, 2006 »
Just wondered if anyone had any information yet on this "new filter" thing. I checked Coronado's site but couldn't find anything there. I am hoping to get a PST from the States next month and it would be good to have this clarified beforehand - don't want to buy the wrong model.

Regards, Kieron
Orion Optics OMC200 / Vixen Super Polaris : Takahashi FS-60C / EQ3-2
ToUcam Pro : Nikon Coolpix 4500

Offline DigitalSky

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Re: PST Extension Tube Removal
« Reply #23 on: 12:56:36, 27 June, 2006 »
Hi Kieron,

I believe it's an energy rejection filter (NickH knows more than I on this matter). As such it must be in the optical train to use the PST safely. Whether Coronado have introduced this from a certain serial number I don't know (all PSTs have a serial number along their side). If you do get one with the ERF in place you'll have to find a non invasive method of achieving focus. I believe (but you'd need confirmation as I don't use this method) a shorty barlow will do the trick.

Another thing that's needed is a means of telling which PSTs have the ERF in place without taking the extension tube out. Anyone know whether it's possible to just unscrew the eyepiece holder/blocking filter part of the assembly and look down the tube (not pointed at the Sun!) on the later models?

Offline Kieron

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Re: PST Extension Tube Removal
« Reply #24 on: 14:28:12, 27 June, 2006 »
Pete,

Thanks for the extra information. I can't believe that its not covered on the manufacturer's website. Presumably if one asked the supplier they wouldn't have a clue either. Hopefully you are right, and Nick has the full SP.

Regards, Kieron
Orion Optics OMC200 / Vixen Super Polaris : Takahashi FS-60C / EQ3-2
ToUcam Pro : Nikon Coolpix 4500

Offline NickH

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Re: PST Extension Tube Removal
« Reply #25 on: 16:49:17, 27 June, 2006 »
NOt had a chance yet to see Ian Pass (he has one of the new PST's ) PST with this "erf" (just my guess at the moment) in place.

I hope to see him soon, but our astro club doesn't meet in the summer months, and getting out with a littleun is a bit difficult at the mo :-)

Will keep everyone posted when I see it for myself, and determine what the deal is.

Celestron C11: DSI-C/Toucam Pro 2 ICX mod and SC1.5 mod/ Meade LPI/EOS300D/ED80/WO80ZS/Shoestring guider. PST/PST CaK/ART285

No time....always bloomin cloudy...need to build the Obsy..

Offline Kieron

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Re: PST Extension Tube Removal
« Reply #26 on: 17:04:43, 27 June, 2006 »
Thanks Nick
Orion Optics OMC200 / Vixen Super Polaris : Takahashi FS-60C / EQ3-2
ToUcam Pro : Nikon Coolpix 4500

Offline AndyJones

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Re: PST Extension Tube Removal
« Reply #27 on: 20:51:09, 27 June, 2006 »
Has anybody here come across a PST which won't focus a toucam with the extension tube removed?

I've removed the tube from mine, but i still don't seem able to focus it..... It almost reaches focus, but it seems like the chip needs to get just a few more mm closer...

Ho hum....

Andy J.
Tal-2M, Skywatcher StarTravel 120, WO ZS66 APO, Coronado PST, EQ3-2, Canon 10D, Phillips ToUCam Pro + MOD.

Offline number26

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Re: PST Extension Tube Removal
« Reply #28 on: 20:52:10, 27 June, 2006 »
I have the new model with the new (ERF?) filter in place. I can focus my 20D with the lens of my Shorty barloe attached to a short extension tud and t-mount.

I have not yet managed to get my Celestron Neximage to focus and would like to do that if anyone has any detailed ideas.

Another question would be to ask if it is possible to machine a new extension or shorten the existing one whilst still making use of the new incumbernt filter....


mmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmmm
Mark

LXD75 6N, Revelation 80, a VERY old C8, Coronado PST, NexImage, Canon 20D

Offline swac3

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Re: PST Extension Tube Removal
« Reply #29 on: 17:22:41, 30 June, 2006 »
No26  Ive been trying without success to find details of the thread size/pitch on the PST
BF and extension tube, I had the idea of replacing the extension bit with one of the low profile
Borg helical focuser's,they do a fair range of adaptors but without an actual thread measurement
its all academic
Gary. 
 Megrez 80 II FD : TV60 : PST Ha+CaK
 Vixen gpdx - ss2k Goto : Toucam  Pro2  :Canon 350d :ASTSC1BW
 Clouds: various types, free to uplift.
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