William Optics UltraCat Astrographs
William Optics UltraCat astrographs are Petzval refractors in the Cat series, built for fast, flat-field deep-sky imaging without a separate flattener. The UltraCat 56, 76 and 108 work at f/4.8 and use WIFD internal focusing.
The Ultra-Cat 131 at f/4.9 is the largest in the line, for more resolution on smaller galaxies and nebulae. The small apertures suit travel rigs, while the bigger ones need a sturdier equatorial or harmonic mount.
Filters
William Optics UltraCat 108 f/4.8 WIFD
108mm Aperture, 5-Element Advanced Petzval Optical Design Fast f/4.8 Focal Ratio with 518mm Focal Length Massive 60mm Flat-Field Image Circle Pate...
View full detailsWilliam Optics UltraCat 56 f/4.8 WIFD
56mm Aperture, 269mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50mm Image Circle for Full-Frame Sensors William Optics Intern...
View full detailsWilliam Optics Ultra-Cat 131 f/4.9 Petzval Astrograph
131mm Aperture 648mm Focal Length (f/4.9) 5-Element Advanced Petzval Optical Design 60mm Flat-Field Image Circle Patented WIFD Internal Focuser 13...
View full detailsWilliam Optics UltraCat 76 f/4.8 WIFD
76 mm Aperture, 365 mm Focal Length (f/4.8) 5-Element Advanced Petzval Optical Design 50 mm Corrected Image Circle William Optics Internal Focusin...
View full details