Stage 2 mod only

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Trent1512
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Stage 2 mod only

Post by Trent1512 » Sun Jun 10, 2012 10:30 am

Hey all,
My quest for full day/full disk time lapse continues, what is letting me down is the optics in the PST, I am considering doing a stage 2 mod only. I have seen posts where adapters are not required and also posts with adapters. What I am wondering is if anyone has after modification photos for comparison of full disk, and possibly the method used to mount the crayford focuser. Any help here would be greatly appreciated.

Trent

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Re: Stage 2 mod only

Post by marktownley » Sun Jun 10, 2012 10:37 am

My experience is that a pst mod for full disk is not ideal - you will still get your sweetspotting issues. I did a comparison in may with a full disk with my 100mm pst mod and double stacked sm40 - you can find it about a 1/4 way down this page http://brierleyhillsolar.blogspot.co.uk ... chive.html IMHO the ds40 was a clear winner despite the extra aperture the mod offered.

How do you consider your pst optics are letting you down? If you just want to do full disk timelapses i'd be tempted to double stack your pst.
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Re: Stage 2 mod only

Post by Merlin66 » Sun Jun 10, 2012 10:45 am

Trent,
Do you have a copy of my PST Mod write-up? There are plenty of examples of different/ various adaptors which can be used for the Stage 2 mod.
(Drop me an email for a copy, if needed.)
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Re: Stage 2 mod only

Post by swisswalter » Sun Jun 10, 2012 3:15 pm

Hi Trent

for full disk shots I would go straight PST or Lunt 60. I will later on in the season make trials with a 500 mm PST mod and let you all now about the results
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

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Re: Stage 2 mod only

Post by Trent1512 » Mon Jun 11, 2012 12:17 am

Thanks for all the responses.
I really feel that the prism in the PST is mis-aligned, and I feel that a crayford focuser with a BF15 and the double stack unit would be best way for me to go. I seem to lack resolution and detail in my current system, which is what I really want. It would be wonderful to be able to chuck my ST-8300 on the backend of a Solar Scope, but this seems like a problem that requires $$$$$$$$$$$$$$ to fix.

Mark,
I own the double stacking unit already for the PST, but I cannot seem to get rid of a ghosting of image when imaging full disk, this is despite hours spent following both instructions and suggestions from other users. The ghosting isn't apparent when working at a smaller field. By the way you have some really inspiring pics there!

Ken,
Thanks for that, I have sent you an email, thanks for all your great work in the modding department!

Walter,
I was hoping that by replacing the back end of the scope with a crayford focuser it would effectively be the same as a straight PST. 500mm full disk is that possible?

Trent

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Re: Stage 2 mod only

Post by colinsk » Mon Jun 11, 2012 1:45 am

You can re-align the prism. I had to on mine and it made a great improvement. I don't miss the PST however. Mine had a band that was a 1/3 field of view that was perfect. The rest was off band.

As far as your reflection on the double stack, it may be too close to on-band at room temp. you can see by trying it in the winter on a really cold day. If that is the case you may be able to salvage the etalon for a "project" etalon.
Thank you, Here are some references I have collected.



Etalon Article Part I

Etalon Article Part II

Solar Patents of interest

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Re: Stage 2 mod only

Post by swisswalter » Mon Jun 11, 2012 4:32 am

Hi Trent


I don't know but I will try to see how even the fields is that I get
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)

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Re: Stage 2 mod only

Post by marktownley » Mon Jun 11, 2012 6:18 am

Ahhhh, I see what you want to do Trent. Yes, that is quite easily possible. Unscrew tube and etalon from the black box, screw on a PST to female "2 adapter, with a SCT focuser fix a 2" adapter into this then you can connect the focuser to the tube. You will need to unscrew the eyepeice holder from the PST which is easy enough - if not hand tight use a boa wrench - this can then be fixed quite easily into a 1 1/4" diagonal. You will need some spacers to get the 200mm distance but should work well. John M http://solarchat.natca.net/index.php/en ... userid-995 has done exactly this, maybe he can post some pics for you?

Are you using a focal reducer at all Trent?
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Re: Stage 2 mod only

Post by Trent1512 » Thu Jun 14, 2012 7:34 am

Mark,
I'm not using a focal reducer at all, my PST has been "shortened" already so I can get full disk onto my DMK-41

Trent

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Re: Stage 2 mod only

Post by marktownley » Thu Jun 14, 2012 10:22 am

Mark,
I'm not using a focal reducer at all, my PST has been "shortened" already so I can get full disk onto my DMK-41

Trent

How did you do this?
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http://brierleyhillsolar.blogspot.co.uk/
Solar images, a collection of all the most up to date live solar data on the web, imaging & processing tutorials - please take a look!

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Re: Stage 2 mod only

Post by Trent1512 » Thu Jun 14, 2012 11:21 am

Mark,
I cut short the eyepiece holder section of the PST, and I also shortened the nose piece of the DMK. This is before I realised it can be achieved by other means. :oops:

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Re: Stage 2 mod only

Post by swisswalter » Thu Jun 14, 2012 4:56 pm

Hi Trent

:thumbsup: ;)
Only stardust in the wind, some fine and some less fine scopes, filters and adapters as well. Switzerland 47 N, 9 E, in the heart of EUROPE :)

from 7 am - 7 pm http://www.nanosys.ch

from 7.01 pm - 6.59 am http://www.wastronomiko.com some times vice versa ;)

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Re: Stage 2 mod only

Post by poita » Tue Jun 19, 2012 2:11 am

How are people mounting their PST after removing the black box? Finder rings?

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Re: Stage 2 mod only

Post by colinsk » Tue Jun 19, 2012 2:14 am

There are adapters for both the front and back. I bought some from a place in Europe. I bet Ken knows who has them now.
Thank you, Here are some references I have collected.



Etalon Article Part I

Etalon Article Part II

Solar Patents of interest

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Re: Stage 2 mod only

Post by Merlin66 » Tue Jun 19, 2012 2:16 am

Usually the PST Stage 2 mod involves a reasonable sized donor OTA (ie >75mm aperture), and as the "black box" no longer exists, the OTA is either mounted with the usual tube rings/ dovetail or a fitted dovetail.
Hope this helps.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Stage 2 mod only

Post by poita » Tue Jun 19, 2012 2:21 am

Ah, I see.
A stage2 only, or for people that have bought the 60mm Denk upgrade though are out of luck on that option.
I'm currently using 50mm finder rings on the DENK model, but it is less than ideal.

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Re: Stage 2 mod only

Post by Merlin66 » Tue Jun 19, 2012 2:23 am

Colin, et al,
Rusty is selling the nosepiece and rear PST adaptors in the US.....
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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Re: Stage 2 mod only

Post by poita » Tue Jun 19, 2012 2:42 am

Rusty?

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Re: Stage 2 mod only

Post by Merlin66 » Tue Jun 19, 2012 2:53 am

"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

Trent1512
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Re: Stage 2 mod only

Post by Trent1512 » Sat Jun 30, 2012 9:16 am

Hi all,
I think I may of confused everyone with my interpretation of the stage 2 mod. What I was implying was only replacing the black box of the telescope, which is now complete as I have just bought a bf10. I look forward to the views that this will provide.

So now I am going to start work on the "stage 1" side of things, for this I plan on using a spare ed100 telescope I own, however I have run into a confusing situation. I have decided to use the 90mm baadar ERF, but I can't seem to find much information on how to mount these filters. If anyone has any advice on what to buy to mount the ERF filters to an ED100 I would really appreciate it

Trent

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Re: Stage 2 mod only

Post by Merlin66 » Sat Jun 30, 2012 3:22 pm

Trent,
The maximum aperture you'll get from a 90 D-ERF, if you're very, very, carefull is about 88mm.
Realistically the 90mm becomes an 80mm after mounting.
In the PST Mod write-up I show various methods of mounting; everything from a "Body Shop" container to a re-used Solar filter cell....
As long as the ERF is secure and slightly tilted - anything goes!!
If you want to spend real money, then Telescope Sevices in Germany can machine a specific cell for you.
"Astronomical Spectroscopy - The Final Frontier" - to boldly go where few amateurs have gone before
https://groups.yahoo.com/neo/groups/ast ... scopy/info
"Astronomical Spectroscopy for Amateurs" and
"Imaging Sunlight - using a digital spectroheliograph" - Springer

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