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Old 03-02-2012, 05:53 PM
rally
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Join Date: Sep 2007
Location: Australia
Posts: 896
John,

I'll assume the scope you refer to is the Tak TOA130NS with the small focus tube.

But in any event the image scale is probably reasonably well suited to an f7.7 especially if you get the 1.6x and 0.66x adapters - I'll assume they wont vignette.

That will give you images scales of 0.7, 1.1 (native) to 1.7 arc secs per pixel - so you have a few bases covered but probably oversampling for suburban skies !
Depends a lot on whether you think you want to do a lot of widefield imaging or spend more time on distant DSO's - from suburban skies the widefield is probably going to be more productive

If you went to the bigger brother STL11000 then your image scales would be 1.1, 1.9 (native) and 2.8 as/p
Which is probably an even better match and covers everything nicely, not sure how the 1.6x and small reducer will illuminate the larger chip area.
Not sure how well the STF and STL is supported with the 1.6x adapter ?
Worth checking and also for backfocus

The new ST8300 can facilitate guiding by adding in extra gear - but by the time you add in the SBIG 8300 OAG, the STi Guider (and 5 pos FW) you are up over $4000US on current specials, closer to $5000US at normal prices.

The STL11000M isnt that much more ! and has all of that built in and the advantage of greater dynamic range with ideal image scale which tends to be one of the not so strong points of the KAF8300 chip.
But at least the 36mm filters are cheaper than 50mm filters !

The EM200 should manage all of that OK.

Cheers
Rally
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