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Jack C. Davis Observatory
The BRC-250 employs non-spherical surfaces for both the primary and secondary mirrors, and when they are combined with two supplementary lenses, eliminates spherical aberration, coma, and even astigmatism with a flat field. It produces a focal ratio of f/5 with a 100mm 5 degree diameter image circle. It also produces an amazing 2 micron stellar image at the center of the field.
The BRC-250 employs the Baker method to flatten the field over a wide field. However, because its primary and secondary mirrors are hyperbolic, production was difficult. Today, Takahashi's unique technique in polishing non-spherical surfaces enable the first mass production of Baker Ritchey-Chretiens.
The extremely small stellar images makes the BRC-250 the perfect instrument for CCD imaging. The 100mm diameter image circle will accommodate the largest commercially available CCD cameras.