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Author Topic: pst tuner  (Read 2239 times)

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Offline astroscouse

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pst tuner
« on: 10:00:00, 01 November, 2012 »
After being transported, PST has developed a strange image shift when turning the tuning ring. A second image emerges from the main image and they diverge and converge just like a rangefinder camera, when they are "centered" so to speak the image is fine. I have dismantled the black box, inspected the etalon etc. but can se no faults. This is most puzzling but no - one seems to have ever had this; is it supposed to be like this or can anyone tell me it's a fault and, if so, what is the cause ?

Richard :confused:
Astroscouse

Offline Einari

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Re: pst tuner
« Reply #1 on: 10:10:29, 01 November, 2012 »
I dropped my first PST and showed similar effects - but I couldn't get a decent image at all.
I think you should contact your dealer.
Tapio

Celestron C8, C9.25" & Hyperstar, iOptron CEM60-EC, TS 80 triplet,  Coronado PST, SXV-694,  ASI120MM/ASI174MC Cool

Offline sdc

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Re: pst tuner
« Reply #2 on: 12:43:47, 01 November, 2012 »
Hi Richard,
 It could be that a knock in transit has de-contacted the etalon. I don't think you would pick this up on a visual inspection of the unit, only  when trying to use it. Normally when an etalon is out of alignment you get either a double image or one focused image that shows no detail at all. If the etalon has shifted, I'm not sure there is anything that can be done wth it I'm afraid.

Regards
Steve
There's a very fine line between a hobby and a mental illness.

Offline Nomis Elfactem

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Re: pst tuner
« Reply #3 on: 13:13:22, 01 November, 2012 »
Yeap, as Steve and Tapio says, it sounds like your etalon has come adrift.  The etalon has two sheets of glass that are incredibly close to each other - these sheets are meant to move in parallel with each other but the symptoms you describe would say to me that this is no longer the case and they are moving in a non parallel plane to each other... (more info can be found here that explains how it works ! http://en.wikipedia.org/wiki/Fabry%E2%80%93P%C3%A9rot_interferometer).

Again, as Steve says I too don't think anything can be done about it...

Is it still under warranty, if so contact your supplier or else would it be covered under any home insurance you may (hopefully) have as either way it sounds like you need a new one ?

S.
Simon

Scopes: Astro-Tech AT-111EDT Triplet, TS65ED Quad, Orion ST80, Modded PST-90 Solar Scope, PST Cak (on loan)
Cameras: SXVF H694, Atik 16ic, Canon EOS 600d, DMK41, DMK21, QHY 5L-II (mono & colour)
Accessories: SX USB Filter Wheel, SX OAG, Baader LRGB Ha SI OII Filters, SharpSky Focuser
Mount: EQ6 (EQMOD), SW Star Adventurer, plus a lot (and I mean a lot) of other bits and pieces

Offline sdc

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Re: pst tuner
« Reply #4 on: 09:55:07, 02 November, 2012 »
It wouldn't be a warranty claim :(  but household insurance can be a wonderful thing. Coronado do not cover de-contacted etalon's as the only way it can happen is a knock (and of course the back unit has now been apart). It's not the end of the world though- as I'm sure something can be done via your insurance
There's a very fine line between a hobby and a mental illness.

Offline Nomis Elfactem

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Re: pst tuner
« Reply #5 on: 11:57:37, 02 November, 2012 »
Good point Steve... in which case fingers crossed you have insurance Richard ?!
Simon

Scopes: Astro-Tech AT-111EDT Triplet, TS65ED Quad, Orion ST80, Modded PST-90 Solar Scope, PST Cak (on loan)
Cameras: SXVF H694, Atik 16ic, Canon EOS 600d, DMK41, DMK21, QHY 5L-II (mono & colour)
Accessories: SX USB Filter Wheel, SX OAG, Baader LRGB Ha SI OII Filters, SharpSky Focuser
Mount: EQ6 (EQMOD), SW Star Adventurer, plus a lot (and I mean a lot) of other bits and pieces

Offline Einari

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Re: pst tuner
« Reply #6 on: 12:59:26, 02 November, 2012 »
Yep, home insurance rescued me when I dropped mine.
Tapio

Celestron C8, C9.25" & Hyperstar, iOptron CEM60-EC, TS 80 triplet,  Coronado PST, SXV-694,  ASI120MM/ASI174MC Cool

Offline joncarruthers

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Re: pst tuner
« Reply #7 on: 08:42:44, 15 January, 2013 »
sometimes an etalon can be recontacted but the result is never as good as it was. Cleanliness is essential, the mica spacers need to be preserved. Finger grease and dust must be avoided.
A tiny drop of pure acetone is put on each of the spacers and then the assembly is pressed together in its correct orientation. Capillary action draws the elements together as the acetone evaporates hopefully leaving the parts held together by cohesion (optical contacting).
Good luck.

 

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