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Author Topic: PST tuning ring performance  (Read 4563 times)

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Offline JohnM

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Re: PST tuning ring performance
« Reply #15 on: 14:21:33, 04 March, 2011 »
I decided to get the FNJS focuser from here:
http://www.scopestuff.com/ss_fsm1.htm
Jim told me who made it, but I've forgotten already.
Not GSO, but another of those big Chinese companies.
I've made scale drawing again now that I know where the etalon needs to be and it looks like this
focuser will provide all the travel I'll need.
Adding a diagonal for visual use might be an issue, but I'll check that out when things are all assembled.

I am a little concerned some flexure might develop. I can see the flocking inside the draw tube I used as a coupling sleeve
beginning to collapse, I could see a sag there after time.
After I've determined the optimal etalon position I think I'll add another set of lock screws and center the gap so everything is held solid.Also need some more good stainless screws to replace the nylon ones I had to use.
That adjustment shouldn't need changing, at least not very often.

All I know is that now the etalon sits where the light cone entering it is ~17mm in the slightly over f10 optics, maybe about f10.3.

Offline JohnM

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Re: PST tuning ring performance
« Reply #16 on: 14:34:15, 04 March, 2011 »
Ken, I wish the 60mm front mount etalon weren't so expensive.
If this thing were DS it might be quite something.
For now I'll be very happy to get back to good sharp images again.

Offline Merlin66

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Re: PST tuning ring performance
« Reply #17 on: 14:48:31, 04 March, 2011 »
I see in the US that the SM60 with a BF10 is down to $699....that's a very good price!!
Anyway,
Once the etalon is correctly positioned it will NEVER need to be moved again....ever....
What you need is a focuser between the etalon and the BF....the total distance to focus is 200mm. I use the Baader micro focuser and a 20mm T thread spacer to allow me to do visual or use the DMK...
C11, C9.25 SCT, 4" Genesis, NEQ6pro, modded 1000D,  ATik314L+, DMK41AF04, SM60DS/BF15, and Spectroscopes (many!).
http://tech.groups.yahoo.com/group/astronomical_spectroscopy/
"Astronomical Spectroscopy for Amateurs", "Grating Spectroscopes-How to Use them" -Springer

Offline Nomis Elfactem

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Re: PST tuning ring performance
« Reply #18 on: 14:53:19, 04 March, 2011 »
I'll have to add up how much my mod cost - I have a feeling all in it's more that the price of a SM60 but I guess mine is at least on a 90mm scope.

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 JohnM

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Re: PST tuning ring performance
« Reply #19 on: 14:54:01, 04 March, 2011 »
This focuser I have coming will let me reach the 200mm optimum nicely.
I've read that all those parts Meade was selling off so inexpensively are gone now, too bad.

Offline Nomis Elfactem

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Re: PST tuning ring performance
« Reply #20 on: 14:55:38, 04 March, 2011 »
$699.... wow, I bet they're twice that in the UK..... not looked recently.

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 JohnM

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Re: PST tuning ring performance
« Reply #21 on: 22:39:32, 04 March, 2011 »
The 60mm with the new focuser installed.

Offline Nomis Elfactem

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Re: PST tuning ring performance
« Reply #22 on: 16:55:07, 05 March, 2011 »
Looking good John !!

Just answered my camera question too.

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 Merlin66

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Re: PST tuning ring performance
« Reply #23 on: 17:09:03, 05 March, 2011 »
John,
I assume the BF10 came with the 60mm mod....you just remounted it behind the focuser??
C11, C9.25 SCT, 4" Genesis, NEQ6pro, modded 1000D,  ATik314L+, DMK41AF04, SM60DS/BF15, and Spectroscopes (many!).
http://tech.groups.yahoo.com/group/astronomical_spectroscopy/
"Astronomical Spectroscopy for Amateurs", "Grating Spectroscopes-How to Use them" -Springer

Offline JohnM

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Re: PST tuning ring performance
« Reply #24 on: 17:27:19, 05 March, 2011 »
Yes, externally it's the same as the stock PST 5mm, just a larger BF element inside.

 

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