First PST Mod Questions and Check

Frankenscope? Let's see it!***be advised that NOTHING in this forum has been safety tested and you are reading and using these posts at your own peril. blah, blah, blah... dont mess around with your eyesight when it comes to solar astronomy. Use appropriate filtration at all times...
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Bojan
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First PST Mod Questions and Check

Post by Bojan » Tue May 03, 2016 2:42 pm

Hi guys,

I have decided to go straight for a stage 2 PST mod and have some questions I just want to verify before everything.
The donor scope is https://www.optcorp.com/stellarvue-sv10 ... scope.html.

I will be using for now, a pre-meade Solarmax 5 blocking filter.
Some concrete questions I have

1) How does one choose a blocking filter? Bigger is better? However much your budget allows? Coronado vs Lunt? I'll be doing both visual and imaging 50/50 split with a Neximage 5.
1a) I understand the function of the ERF and etalon. What wavelengths does the blocking filter actually cut out? Does it just cut down the intensity?

2) Is a UV/IR filter necessary? Or is the combination of ERF and blocking filter sufficient?

3) Unrelated to the PST Mod, but why does a long focal length F/11 achromatic refractor have less (apparent?) chromatic aberation than say a f/5 refractor? I'm technical so would appreciate a technical response.

4) How close does the ERF have to be mounted to the objective? Can it be a few cm? Or as close as possible?

5) I will be using a Lunt ERF for this Mod. Is the transmission profile similar for the Lunt as the Baader?

Thanks,

Bojan
Last edited by Bojan on Wed May 18, 2016 2:30 am, edited 5 times in total.
Pre-Meade Solarmax40
Lunt 2" Wedge on ES 127mm Apo
Some photos and hobbies at:
https://bojanscepanovic.wordpress.com/c ... -outreach/

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marktownley
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Re: First PST Mod Questions and Check

Post by marktownley » Tue May 03, 2016 3:15 pm

Hi Bojan

Just thinking out loud here; if you haven't bought that donor scope already why don't you just use the 127 you have already and stop it down to get to f10?

Mark
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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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Bojan
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Re: First PST Mod Questions and Check

Post by Bojan » Tue May 03, 2016 3:44 pm

2 fold.. I enjoy doing outreach with the Charlie Bates Solar astronomy project so would require two scopes, and the 127mm triplet seems overkill for this task, then again it's overkill for white light duty, but also wouldn't want to cut into it if it came to that.

But now you have me thinking, I have a small Orion ST80 which could go to white light duty, and the 127mm could get by with a 90mm ERF to stop it down...

Now I have more questions lol.
marktownley wrote:Hi Bojan

Just thinking out loud here; if you haven't bought that donor scope already why don't you just use the 127 you have already and stop it down to get to f10?

Mark
Pre-Meade Solarmax40
Lunt 2" Wedge on ES 127mm Apo
Some photos and hobbies at:
https://bojanscepanovic.wordpress.com/c ... -outreach/

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solarchat
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Re: First PST Mod Questions and Check

Post by solarchat » Tue May 03, 2016 9:15 pm

Bojan, meet Mark, the UK Director for CBSAP.
Mark meet Bojan, the Canadian Director for CBSAP
Stephen W. Ramsden
Atlanta, GA USA
Founder/Director Charlie Bates Solar Astronomy Project
http://www.solarastronomy.org

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Bojan
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Re: First PST Mod Questions and Check

Post by Bojan » Tue May 17, 2016 3:52 pm

Bump for my original questions.
Pre-Meade Solarmax40
Lunt 2" Wedge on ES 127mm Apo
Some photos and hobbies at:
https://bojanscepanovic.wordpress.com/c ... -outreach/

antonello
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Re: First PST Mod Questions and Check

Post by antonello » Fri May 20, 2016 5:27 am

Bojan wrote: 5) I will be using a Lunt ERF for this Mod. Is the transmission profile similar for the Lunt as the Baader?
Hello
I was in charge of recent solar astronomy
and in our laboratory I have done many tests on solar filters (BF, ERF, etc.).
This is the graph of the transmission curve of three different ERF, the first is the traditional Baader, the second is the ERF lunt and the third is an ERF realized with two photo filters:
B+W 091 (RG630) plus B+W 486 (UV-IR cut).
All my tests have confirmed that the quality of photographic filters of this third ERF does not degrade the image quality in visual observation.
Attachments
CURVE_DI_TRASMISSIONE_ERF.jpg
Last edited by antonello on Fri May 20, 2016 8:13 pm, edited 1 time in total.

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Bojan
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Re: First PST Mod Questions and Check

Post by Bojan » Fri May 20, 2016 3:11 pm

Thank you! Raw data is always better. That answers most of my questions now :)


antonello wrote:
Bojan wrote: 5) I will be using a Lunt ERF for this Mod. Is the transmission profile similar for the Lunt as the Baader?
Hello
I was in charge of recent solar astronomy
and in our laboratory I have done many tests on solar filters (BF, ERF, etc.).
This is the graph of the transmission curve of three different ERF, the second is the ERF lunt and the third is an ERF realized with two photo filters:
B+W 091 (RG630) plus B+W 486 (UV-IR cut).
All my tests have confirmed that the quality of photographic filters of this third ERF does not degrade the image quality in visual observation.
Pre-Meade Solarmax40
Lunt 2" Wedge on ES 127mm Apo
Some photos and hobbies at:
https://bojanscepanovic.wordpress.com/c ... -outreach/

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