PST mod1 on a C8 without ERF

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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DSobserver
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PST mod1 on a C8 without ERF

Post by DSobserver » Wed May 20, 2015 6:58 pm

Following some previous discussion here on the forum, I was thinking how to do aPST md on scope bigger than 180mm (biggest ERF on the market)

The idea was to use several small 2"UV/IR cut filter like an interferometry scope.

Loic (zordotnl) show us thatit looks feasable :

Image

Our last french solar meeting last week was the right moment to try this on a C8 SCT using x3 2" UV/IR cut baader filter on a home made mask :

Image

Previous night, star test surprisingly show us exactly the same expected picture. This tell us that most probably as said, 5 filter would be perfect to get a good enought picture.

We placed a pst body on its back protected by an other UV/IR cut filter (just in case):

Next sunny day, we place the scope on teh mount placing our hand on the focus point in order to make sure that IR cut was good.
1 filter : ok, no burning sensation
2 filters : ok, no burning sensation
3 filters : ok, no burning sensation

Lets place the now the PST black body!
Image
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First good news was that we could achieve the focus, but do to only 3 filters, the picture wasn't as good : on top of the expected sweet spot, we had a picture only on the 3 directions like this flower :
Image

Even if weather condition were bad, we could achieve some shot between the clouds :

Image

Image

Next time I really think that it would be really interesting to try this with 5 filters!

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Re: PST mod1 on a C8 without ERF

Post by swisswalter » Thu May 21, 2015 4:18 am

Hi Vincent

a good start
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: PST mod1 on a C8 without ERF

Post by Derek Klepp » Thu May 21, 2015 4:23 am

Very interesting

antonello
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Re: PST mod1 on a C8 without ERF

Post by antonello » Thu May 21, 2015 6:14 am

Sorry, maybe you get a better result by putting in front to telescope an astrosolar Baader photographic sheet and behind, before the PST, an ERF by two inches?
Antonello

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Re: PST mod1 on a C8 without ERF

Post by DSobserver » Thu May 21, 2015 11:06 am

antonello wrote:Sorry, maybe you get a better result by putting in front to telescope an astrosolar Baader photographic sheet and behind, before the PST, an ERF by two inches?
Antonello
I doubt : the astrosolar will block to much light!

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Re: PST mod1 on a C8 without ERF

Post by antonello » Thu May 21, 2015 7:03 pm

Yes, I think you're right... I had not checked the transmission of a photographic Baader Astrosolar (T = 0.00015) ...
Unfortunately, it is sad to see the noticeable drop in quality with the three filters (but also with 5 filters, I think...) ...
DSobserver wrote: I doubt : the astrosolar will block to much light!

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Re: PST mod1 on a C8 without ERF

Post by DSobserver » Thu May 21, 2015 9:15 pm

I'm desagree with you :

we clearly see the chromosphere on the picture and it means that we have already a definition > 100mm scope!

Remember that the sky condition was a disaster between heavy clouds!

Regarding 5 filters, we know that it will boost the quality :

Image

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Re: PST mod1 on a C8 without ERF

Post by antonello » Fri May 22, 2015 6:24 am

DSobserver wrote: we have already a definition > 100mm scope!
This is exactly what I wanted to say...
Having a 200 mm and see as a 100 mm is not (for me) pleasant :( . (I have also a telescope Tal 100 mm, with internal etalon lunt, and I know exactly what I can do with him).

Naturally, my speech was not for belittle your tests... ;)
Also I look with interest your experiments, useful if one has only a C8 ...

I wait with interest and curiosity to see the results with 5 filters.

Thank you.
Last edited by antonello on Sat May 23, 2015 5:47 am, edited 1 time in total.

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