Askar SQA55 Telescope 55mm Aperture F4.8 Quintuplet Air-Spaced SD Glass Petzval Astrograph Refractor for Deep Sky Astrophotography and Visual Astronomy

Quintuplet air-spaced lens design, including 1 piece of SD glass and 1 piece of ED glass. The central star point has an RMS radius of less than 2.5 um, and the star point at the corner is less than 4 um, showing a superfine star point. Self-flattened design, no need to calculate specific back focus,between 50mm and 60mm connection distance, users can directly use it for shooting after the OTA is in focus. The aperture range of the lens is from F22 to F4.8, with a graded adjustment ring and a scale labeled on the lens tube to prevent accidental touching and save the adiustment parameters. There are four multi-functional quick-release bases on the rear of the lens tube, which can be used to connect various accessories for photography and astrophotography,and can also be perfectly matched with the accessories of the SOA series. The lens tube and 360" rotator both have independent locking screws.For daily shooting, the whole body can be rotated.For astrophotography, the high-precision rotator can be rotated independently, while the rotator is engraved with a scale, which is convenient for adjusting and saving the angle.