Five positions in the filter wheel is mostly enough for LRGB or CRGB filter set used by deep-sky photographers. Five positions is also enough for scientific applications, utilizing photometric UBVRI or CBVRI filter set. But some researchers need another filters—e.g. Hα, which can be used for instance for distinguishing a nova from ordinary star (nova Hα emission is more intensive compared to ordinary star, so the nova appears brighter in this spectral line).

The reasons above resulted into introduction of an alternate filter wheel for G2CCD cameras. The new filter wheel diameter is exactly the same, but smaller filters (1" compared to 1.25") allowed to place 6 filter sockets around the circle instead of 5.

Because the camera firmware handles the new filter wheel somewhat differently, it is not possible to simply replace 5-position wheel with the 6-position wheel in existing cameras. Camera must be ordered with the wheel type specified. If the type has to be changed later, camera must be sent to manufacturer for firmware update.