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PST ERF

Posted: Sat Aug 12, 2017 1:34 pm
by Solar B
Hi Folks

I have been using a DS SM60 II recently and have been impressed with the views , but especially their ease and brightness !!
this is obviously because the internal etalon is devoid of an ERF.

This has me thinking that any DS system say 60mm and under would benefit from only utilising one ERF for visual use ,
I have seen an LS 50 DS for sale previously which had the frontal stack ERF removed.

But then how's about the humble PST , my question/s is how easy would it be to remove its ERF (2nd Gen clear blue obj / 2006)
as I reckon this would make its DS image much more accessible.

Plus while I'm on the topic does the factory 0.5A PST only have one ERF like its larger siblings ?

Thanks .... Brian

Re: PST ERF

Posted: Sat Aug 12, 2017 4:31 pm
by Merlin66
You could remove the ITF from the eyepiece holder.....
But in my honest opinion the extra 10% transmission is a minimal improvement.....
All the DS PST I've see still have the internal ITF in place, so they all effectively have two ERF in the optics.

Re: PST ERF

Posted: Sat Aug 12, 2017 5:38 pm
by Solar B
Ah Right Thanks Ken

I hadn't realised that , that was the ITF ... I tried a UV/IR cut in the bf15 of the 60 yesterday (instead of the ITF) and did notice what I thought was a significant drop in contrast so reverted to the ITF ... but will try the PST DS with and without it.


Brian