The APM Model 1 field flattener is intended specifically for refractors with focal ratios from F6 to F7. A sister design, the Model 2, is for F7 to F8 refractors. The flattener has been designed by Massimo Riccardi for APM Telescopes to provide a 60mm flat field. It currently represents the limit of what is possible. There is no comparable flattener with such a good apochromatic longitudinal and lateral aberration correction on the market. Other cheaper models fall short significantly , which is already obvious by their significantly higher vignetting but mainly by the drastically higher inferior lateral chromatic aberration they typically exhibit.
These flatteners represent the perfect match for all our refracting telescopes for those seeking the best possible performance from a 1.0x flattener. For those seeking similar performance from a reducer, then we offer the APM Ricarrdi Reducer.
|Camera Side Thread||M68 Female|
|Telescope Side Thread||M82 Male|
|Back Focus||>90mm (Telescope Dependent)|