Specification:
Aperture：72mm
Focal length：400mm
Focal ratio：F5.6
Objective type：Quintuplet dual ED air-spaced APO
Overall length：317mm
Net weight：2.56kg
Standard package weight：2.88kg
Back-end adapter：M68×1 male thread, 2" adapter/1.25" adapter
Accessories: a pair of tube rings, a handle, a dovetail plate, a M68-M48 conical adapter, an inspection list, a manual
The Askar new FRA400 F3.9 full-
frame reducer reduces the telescope’s effective focal ratio by a factor of 0.7x, thus an original f/5.6 becomes an f/3.9 system, your exposure time will significantly shorten, providing a shorter, more optically “fast” focal ratio to make astrophotography more efficient. It designed for use with FRA400 refractor, providing a 280MM focal length for a wider imaging field of view. It achieves the 55MM back focus, and conveniently threaded for use with M48X0.75 (2") filters.
