Askar FRA400 0.7x F3.9 Reducer for 72mm FRA400 and 90mm FRA500 Astrographs # FRA400FR
| Article number: | FRA400FR |
| Availability: | More on the Way to us |
| Delivery time: | More on the Way to us |
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.