Having tackled the problem of raising and lowering the main shutter, the lower hatch at the front of the dome was tackled using a 12v DC servo motor with a worm driven rod linked to the right side of the inner frame of the lower shutter. When operated this would push open or close the lower hatch depending on the polarity applied to the motor. The motor was obtained from the orient via ebay and a small bracket cut out of aluminum sheet used to mount it to the inside of the main arched beam on the right close to the base. The best mounting site for the motor to provide the desired range was found (as usual) by trial and error and a few tentative screw holes remain as evidence.
The opening of the front hatch was purposely kept to about 10 degrees. This limits viewing at very low angles but this was not considered necessary in view of the buildings nearby and to some extent shielded the OTA from street and house lighting.