How much vignetting will there be using the MAXfield?
Of course, that depends on a number of factors. The MAXfield will provide an 11mm diameter unvignetted image which will cover most chips in the small to medium size class. In practice, you may see some vignetting depending on the telescope as well as the camera. With our ST-6 camera (TC-241 CCD with a diagonal of 11mm) we see about 8% vignetting using the standard 2″ rear cell mount on our 10″ SCT. The standard SCT rear cell thread is an (approximately) 2-inch diameter male thread. On the 10″ and larger class telescopes the rear cell can be removed to expose an even larger 3-inch diameter thread. Using the JMI Large-Format Adapter with an NGF-S focuser, we virtually eliminated all vignetting in our system.
