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Wa-hey! My new Coronado PST

lukebl

By lukebl
in Observing - Solar

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lukebl

lukebl

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I have read elsewhere that the components of current PST models are glued to prevent them being dismantled and modded. Is this true? If so, that'll presumably put the kibosh on any modding efforts?

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Peter Drew

Peter Drew

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It's certainly true that some current models of PST are more difficult to dismantle than others though I've yet to hear of anyone ultimately to be unsuccessful with theirs. I have one where I just cut the "gold" tube off a few inches in front of the etalon tuner and used the black box assembly as a Ha eyepiece which I could then attach to a variety of donor OTA's. A thin sleeve was needed to increase the "gold" portion from 50mm to 2" fit and I made a suitable junction sleeve to reassemble the original PST for grab and go use. My current main main mod is a 6" F10 with internal Baader 110mm ERF and a Coronado BF15, total cost around £1500 using some S/H parts. :smiley:

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Stu

Stu

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I understand from Ken that the stage 2 makes a big difference, is that because of the limitations of the Penta prism in the black box?

I think I will build some confidence and understanding with a stage 1 first before going any further!

Stu

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Peter Drew

Peter Drew

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Stage 2 certainly makes a difference if there is a problem with the pentaprism, I've done some mods with and without and can see little difference in some cases. Worth trying the stage 1 first and see if you are happy with the results. :smiley:

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Merlin66

Merlin66

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The PST mod write-up is available on request - just need an email address.....

The Stage 2 mod also allows much better access to the backfocus ie for DSLR etc.

A Stage 1 mod maintains the restrictive PST focus position.

Whether the ERF is located on the aperture or internal, it should be slightly tilted to avoid ghosting....

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allcart

allcart

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I can offer one tip, that I found out for myself when dissmantling my pst. My gold tube had previously been removed, but the etalon was stuck firmly in the black box with locktight. I removed the rubber grip, removed the small screw and slid the tuner off of the etalon. The tuner was lightly greased so has to be thoroughly cleaned, but even so, my Boa wrench kept slipping. The solution was to wrap some masking tape 3 or 4 times round the tuner and then use the boa. The added grip made the job very simple.

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Merlin66

Merlin66

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Put it this way...

If your camera won't focus on the original PST, it will not focus on a Stage 1 mod.

Nothing in the optical train changes (other than the size of the objective). The backfocus of 200mm remains.

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Luke

Luke

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Congrats on the solar scope!

Doing astronomy during the day while you're not tired and freezing cold, with the sun beaming down on you, looking at a dynamic object that's always changing, that lets us look at a star close up. What's the appeal? :grin:

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allcart

allcart

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Ever sat in front of a blazing bonfire on a freezing cold night, staring into the white hot embers and watched the flames dancing in front of your eyes?

Ever stood on the rim of an erupting volcano and gazed, mesmerized, into the heart of the inferno?

Ever stared death in the face and felt excited about it.

Thats the appeal. :cool:

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DrRobin

DrRobin

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Coronado seem to use copious amounts of Loctite on every joint and it can take some shifting. When I disassembled my PST, I had to wrap some self amalgamating tape around the barrels and use a pipe wrench on it. My Boa wrench just slipped.

Whatever you do, I am sure you will enjoy our sun, prior to buying a PST, I couldn't have ever imagined spending so much on a small scope, now I get 5x the use out of my solar scope than I do my night time scopes and it makes it easier to justify.

Robin

PS lucky you to work from home, my solar scope spends a lot of time in the boot of my car, ready for action.

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trev27

trev27

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Coronado seem to use copious amounts of Loctite on every joint and it can take some shifting. When I disassembled my PST, I had to wrap some self amalgamating tape around the barrels and use a pipe wrench on it. My Boa wrench just slipped.

That's for sure. I broke 3 (yep 3) Boa Constrictors trying to get the eyepiece extension off so that I could achieve webcam focus without a barlow. They didn't have so loctite much on the older type PSTs. It was only when the mods started appearing a few years back that they started doing this :(

Enjoy the PST - they are fantastic wee things!

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Merlin66

Merlin66

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Trev,

Being in at the very beginning of the PST mod "movement" and somewhat responsible for over a hundred successful mods since then, I don't feel my efforts resulted in the extra Loctite on the PST!

What I do know, based on my experiences, is that after Meade/ Coronado transferred the assembly of their scopes to Mexico they DID use much more Loctite on the PST threads.

I can't vouch for any other Meade Mexican assembled products........

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Macavity

Macavity

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I loved my PST, but it had to be sacrificed to a period of financial hardship. :undecided:

Next time, looking seriously at Lundt too. Never overly keen on using force...

But I would not deprecate it's use by the more adventurous and/or patient! :p

Solar Astronomy, the modding possibilities... the (local SGL) enthusiasts... :cool:

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nytecam

nytecam

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Put it this way...If your camera won't focus on the original PST, it will not focus on a Stage 1 mod.

Nothing in the optical train changes (other than the size of the objective). The backfocus of 200mm remains.

Hi Ken - for what it's worth I've found the back focus of my unmodded PST can be increased a few millmetres eg sufficient to reach focus on my Lodestar CCD, with a plane-parallel glass 'filter' eg stack of 1-1/4" filters that transmit red light immediately before the camera ! :cool:
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