The Astro-Physics 92mm Stowaway

The A-P Stowaway is a 92mm air-spaced triplet apochromat designed by Roland Christen using Hoya FCD100 glass. According to Roland, "the lens has broad band multi-coatings on all surfaces. Optimization was chosen for the polychromatic Strehl ratio to be above 90% for the entire visual spectrum with a peak value of 99.8% at the visual peak. The result is unprecedented color correction of +/- 0.003% focus variation from 656 nm to 436 nm (c to g wavelengths)."