Quote:
Originally Posted by multiweb
The QHY9 mono is a pretty small sensor so you don't need a huge corrected imaging circle. You'll be alright IMHO.
|
Thanks,
The design of both the 12" f/3 & the 10" f/4 seemed to call for a larger focuser -
a 3" type otherwise there was 75% vignetting at the focuser.
Maybe I'd get away with it using only a KAF8300 chip with a 22mm diagonal?
Anyway Theo replied & it's ok to remove the nose piece & connect
the QHY9m camera directly to the filter wheel.
Then I gain another 15mm at least giving me 70mm - 15mm = 55mm of back focus.
This corrector:
http://www.teleskop-express.de/shop/...orr--Feld.html
A 3" type from ASA - top quality - allows 58mm of back focus
so I would have 3mm up my sleeve to place spacers.
Removing the nose piece only causes more power to be used to cool the camera
as it must cool a greater quantity of air.
On hot days I might not be able to reach the -30°C I have been using - maybe only -15°C .
cheers
Allan