ERF where and which? 150mm refractor

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LorenzoM
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ERF where and which? 150mm refractor

Post by LorenzoM »

Hello to everyone!
I am starting to prepare the path for the new QUARK cromosphere version...maybe I will be one of the first to receive a Quark in Italy :D
I would like to have a final refractor to do solar images Halfa with PST modified and new quark and white light!
For this reason i am taking a bresser 152/1200 refractor, i think i will use a baader glasspath corrector to bring the focal ratio closer to f/10.
The question is about the ERF.
I would like to put the ERF inside, but where? could be put on the focuser drawtube (inside optical tube)? The focuser is 2" for this reason i could use a 50mm ERF really cheap!!!!
Do you think could be ok?
The second question is which brand? Lunt produces ERF of 50mm and 75mm. The baader only the last size but lunt is cheaper!
From your experience the two are more or less equivalent?

Finally someone have used this telescope? What do you think?

Thanks and i hope to show the first images soon!


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Merlin66
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Re: ERF where and which? 150mm refractor

Post by Merlin66 »

IMHO I'd use a 75mm internal ERF - a 2" filter may give you trouble (overheating?)
The PST mod works best with a native f10, but I think a Baader corrector should work well, based on others results.
I found that a 150mm scope was a bit too bulky, and the seeing conditions really never got the best out of it.
The solar aperture "sweet spot" seems to be around 100-125mm.
I ended up with the TS102 f11 as my PST mod "donor, now use it with a Baader Herschel wedge and an upfront SM60 for double stacking. I still use a full aperture Baader D-ERF.
Hope this helps.


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swisswalter
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Re: ERF where and which? 150mm refractor

Post by swisswalter »

Hi Lorenzo

good luck on the mod. I used a 2" ERF in my 152 f/8 . It was getting very hot, I would not recommend it for a sunny Italien day doing several hours of pointing at the sun. In each case, make sure the ERF is sitting loos in the housing (thermal expansions)


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marktownley
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Re: ERF where and which? 150mm refractor

Post by marktownley »

I think a 50mm ERF on the focuser draw tube will get fried very quickly.

Personally, In this case, I would use the scope stepped down to 120mm (to give f10), and use as large an aperture Baader D-ERF as possible - ideally up front...


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