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 |
Askar provides a brand-new F3.9 full-frame reducer for the FRA400 astrograph, further reducing the focal length and shortening the exposure time on its original 400mm focal length and f/5.6 focal ratio design basis. The reduction factor is 0.7×, which brings the reduced focal length to 280mm. This makes the F3.9 reducer ideal for most deep-sky astrophotography applications. The back focus is a standard 55mm, and the reducer has a built-in M48×0.75 thread, making it easy to attach 2" filters.
Specifications:
- Focal Length (After Reduction): 280mm
- Focal Ratio: f/5.6 (Original), f/3.9 (With Reducer)
- Reduction Factor: 0.7×
- Back Focus: Standard 55mm
- Thread Type: M48×0.75 (for attaching 2" filters)
