Here's another option:
http://shop.tecnosky.it/Articolo.asp...cnocap&Score=1
Translation: Motorized cap with variable adjustment flat, indispensable for telescopes in remote observatories!
The Tecnocap is supplied complete and ready for installation; the stepper motor with 1: 120 reduction manages the opening and closing of the cap with extreme precision, you can choose between the totally closed, totally open position and other 2 intermediate positions. In addition, a timer is available to close the cap at a determined time if an Ascom automation software could not be used.
A Tecnosky flat sheet is applied to the cap and is controlled by the same control unit: through the supplied software it is possible to vary the brightness of the flat from 0 to 255.
The whole system is ASCOM compatible and support from the Voyager automation software
Neat that it can function as a light box for flats as well:
https://www.youtube.com/watch?v=t6g2wm-XUCM