|
I was thinking of using my Baader MPCC which has a 55mm back focus.
In theory this would give me better flats as the camera sensor would be closer to the focuser.
My RCC1 that I use now has a back focus of of 91.5mm which allows me
to use a TS9 OAG , a QHY9 filter wheel, the camera nose piece & a Varilock spacer.
This very long 91.5 mm is probably why my flats are 30% down in the worst corner.
Can it work?
Calculation.
CCD Back focus 15mm from CCD surface to M42/0.75 screw plane -
( that is from the camera manual.)
The distance from the glass output side of the coma corrector to the front face of the camera is about 65mm.
( I measured that & it's more than expected because of my TS9 OAG )
add 15mm for the depth of the KAF8300 sensor chip.
64 + 15 = 79 mm
subtract the length required for the Baader MPCC
79 – 55 = 24mm = too far from the required 55mm
Removing the nose piece & using an adaptor would subtract the 12mm
nose length but add say 3mm for an adaptor so only gain 9mm.
therefore 24 - 9mm = 15 mm = still 15mm too long for the Baader MPCC.
So removing the nose piece of the QHY9 still wouldn't work with the Baader MPCC.
Is there a coma corrector that would work for better flats?
cheers
Allan
|