3.5" Prime Focus Field Flattener for 130GTX serial #130GTX-600 to 130GTX-899 (13035FF-2)

December 2022 - Two new field flatteners were introduced to optimize performance of all 130GTX scopes and 130GT scopes (upgraded to the 3.5" focuser). Field flatteners are designed to accurately compensate for the inherent field curvature of a refractor lens. For each lens design there is an optimal spacing that works best for sharp focus over the specified field size. When the refractor lens design changes even slightly, the field flattener may need to have different spacing for highest performance. This is now especially important when using the newest CMOS cameras with pixel sizes of 3.76 microns and smaller. When producing refractor objective lenses we make the best design possible using the glass index data supplied to us. For the first 3 runs of the GTX lenses (serial# 600 to 899) the glass was the same and we designed the field flattener for those lenses. In the latest runs starting in 2020 (serial# 900 to 1088 and later) the glass data was slightly different and produced a desi