Commercial digiscope adapters for afocal photography are heavy, bulky, and prevent visual use of the scope. I decided to try afocal imaging via the axial port on my Questar. I built a custom digiscope mount that uses the Questar camera connection kit, a small shelf for the camera, and a spare T-ring as a nut to hold the shelf to the connection kit with eyepiece in an afocal configuration. The mounting is rigid and doesn't interfere with visual use through the eyepiece port. I used my Sony RX100, but any point and shoot should work with a custom fit shelf.
The optical adapter train: Questar swivel adapter, 1/2" extension tube, eyepiece mounting ring, 1/4" extension tube, 1/2" extension tube, 24 mm Brandon eyepiece, P to T-ring adapter, T-ring nut. I've found using a spare T-ring as a nut very useful for several camera projects. It avoids the need for a machinist to cut 42mm treads for secure mounting.
The custom mount shelf was made from a 4”x5” aluminum chassis, some scrap oak, and plexiglass to create a rigid shelf that bolts to the optical chain with a T-ring placing the camera lens right up to the eyepiece.
The assembled adapter with the Sony RX100 ready to thread into the Questar axial port.
The afocal adapter and camera mounted on the Questar
A full disk afocal image of the Moon:
An afocal image of the great nebula in Orion:
Content created: 2016-06-08
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