Quote:
Originally Posted by xa-coupe
Thanks Martin.
It's a 6 inch with a dual speed focusser too. I am dreading the day I have to collimate as I've no real idea how to do it .. but like all these things I'll manage!
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I know it’s a 6” aperture but I was asking about about focal ratio f5 or f6
f5 focal ratio means its focal length is 750mm long ( OTA tube length about 800mm )
f6 focal ratio means its focal length is 900mm long ( OTA tube length about 850mm long )
I chose the f6 over the f5 to reduce Coma a bit and with a longer focal length can attempt most of the brighter galaxies from Sydney Bortle 8 ( Centaurus A , Sombrero, M83 , NGC 253 , Pavo and a few others )
I can assist you with Collimation later , once you’ve done it a few times it’s a 5 minute job , easy ( not so easy with a 12” like my Goto dob )
Cheers
Martin