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Re: Baader 35nm as ERF

Posted: Sat Jan 12, 2019 6:26 am
by marktownley
Hi Andrew,

You could use a MagniMax barlow from astroboot https://www.astroboot.co.uk/AstroBoot/t ... eedle=1.25 right infront of the negative collimating beam which would turn the f7.5 light cone towards the target f10.

Mark

Re: Baader 35nm as ERF

Posted: Sat Jan 12, 2019 9:13 am
by AndiesHandyHandies
Hi Mark,

Thanks for the link.

With a 1.25" Barlow all the energy would be on a 1.25" filter behind a collimator.

What I was thinking about the ERF being behind a collimator will not work here. And not needed as reflected focus inside the telescope.

127mm F7.5

Need a 1.33x barlow for F10.

The PST Collimator lens will be 200mm from the new focus which from graphing is 150mm inside old focus.

A 2" filter has a 45mm clear aperture so it needs to be 338mm inside the original focus to spread heat over all of the filters.
The reflected heat is expanding 70mm diameter at the objective.

A 1.25" Barlow with 24mm aperture has to be within 200mm of original focus to not vignette, 50mm back from PST Collimator lens.
A 2" Barlow can go from <318?mm to 180mm inside the original focus, allow 10mm for 2" thread. A Barlow threaded each end 2" will fit in a stack of 2" filters and extenders with 48 to 42 and 42mm to PST adaptor on the back.

Possibly need to still use the PST collimator lens seperate infront of the PST body to reach focus? Without hacksaw.

Andrew.