Astromania Deluxe Off-Axis Guider for Astrophotography
... possibly ruin the tracking accuracy if you use an off axis guider..
1) Can be used with correctors & DSLR: The only Off Axis Guider that can be used between a coma corrector (or field flattener) and a DSLR camera without leaving the tolerance for the distance between camera and corrector. 2) Can be used with cooled CCD cameras: The off axis guider provides enough space for filter wheels or filter drawers when using cooled CCD cameras..
Place the OAG behind the corrector: The Astromania OAG is used between the corrector and the camera. Using an off axis guider in front of the corrector is not useful. The guide star would be distorted, the distances on both optical paths are too different and you might even get focusing problems with the main camera. Behind the corrector you can avoid these problems, but this only works due to he low profile of the Astromania OAG!.
Large Clear Aperture: Compared with many simpler guiders the Astromania OAG not only has a shorter overall length, but also a larger clear aperture. A "T2 keyhole" can be avoided, resulting in better illumination for large sensor cameras up to 45mm diagonal.The load for the mount is much reduced. There is no need for a guide scope and the setup will remain more compact. You work with the main ....