Just figured I'd share my latest discovery which allows me to get full prism illumination on my SXV80T without blocking any of the filter or sensor. Uses the light cone more effectively than trying to squeeze everything out of a 48mm light cone... swapped out the 3mm thick m69-m54 adapter on the back of the flattener for the m69-m68 3mm thick adapter:
hope it helps someone:
ZWO m68 sensor tilt plate (5mm)
+
ZWO OAG-L (17.5mm)
+
one half of a ZWO T2 Tilter (5mm)
+
T2 adapter (2mm)
+
ZWO 8x 1.25" EFW (20mm)
+
ASI294MM (6.5mm)
=
56mm
no vignetting, full prism illumination, full 174mm sensor illumination, EAF slightly off axis from main sensor but hasn't affected guiding at all, plus you don't need additional spacers to get the prism aligned to the sensor which messes up back focus.... Wasn't included in ZWO's 55mm back focus examples so I figured I'd share.
hope it helps someone:
ZWO m68 sensor tilt plate (5mm)
+
ZWO OAG-L (17.5mm)
+
one half of a ZWO T2 Tilter (5mm)
+
T2 adapter (2mm)
+
ZWO 8x 1.25" EFW (20mm)
+
ASI294MM (6.5mm)
=
56mm
no vignetting, full prism illumination, full 174mm sensor illumination, EAF slightly off axis from main sensor but hasn't affected guiding at all, plus you don't need additional spacers to get the prism aligned to the sensor which messes up back focus.... Wasn't included in ZWO's 55mm back focus examples so I figured I'd share.