Astrodon - Camera Adapters

MOAG means Manual Off-Axis Guider, a
non-moving part of your optical train. 

The MegaMOAG™ is the largest member of our off-axis guider
product line.  It is specifically designed to accommodate the larger CCD
detectors (36 x 36 mm), such as the Kodak KAF16803E and KAF9000E used on
larger telescopes with 4" accessories and extension tubes. It is a 4"-to-3"
version of our popular  MegaMOAG™, where the camera side accepts
all 3" MegaMOAG™ adaptors.  Furthermore,  it retains the thin
1.25" backfocus of MegaMOAG™, and is an ideal choice for systems
having minimal backfocus such astrographs made by Dream Telescopes. It also
integrates nicely with the 4" systems at the back of larger RC Optical
Systems Ritchey-Cretien telescopes.  

MOAG means Manual Off-Axis Guider, a
non-moving part of your optical train.