The 0.75x reducer can bring Askar 71F's focal ratio down to F5.2. This is a standard reducer with field flattening capabilities as well. A shorter focal ratio allows the OTA to have a wider field of view and faster exposure times, making it suitable for capturing large areas of nebulae, star clusters, and faint, fast-moving celestial objects.
The 0.75x reducer adopts a triplet design and supports a 44mm full-frame image circle. The overall weight is 0.23 kg. The back focus from the M48 thread is a standard 55mm. Both end threads are M59*1. The 71F photographic extension tube has two sizes of M54*0.75 and M48*0.75 adapters, which can be directly and easily connected to the 71F 0.75x reducer for use. At the same time, the adapter has a built-in M48*0.75 2-inch filter thread, which can be directly installed and used. The overall CNC machined, both end threaded metal caps prevent ash when not in use.
|
（After attaching）71F Focal length |
369mm |
|
|
（After attaching）71F Focal ratio |
f/5.2 |
|
|
Lens Number |
Triplet design |
|
|
Back Focus |
55mm（from the base of M48 male thread） |
|
|
Weight |
0.23kg |
|
|
Rear-end thread type |
M59*1 |
|
