Askar FRA400C 0.7x Full Frame Reducer
User's Manual
Website: www.sharpstar-optics.com
Important Safety Information
DO NOT LOOK AT THE SUN THROUGH THE TELESCOPE. IT WILL CAUSE IRREVERSIBLE DAMAGE TO YOUR EYE. Use a dedicated solar observation filter or film for safe solar viewing.
Product Description
The Askar 0.7x reducer is specially designed for the FRA400C telescope. It features a triplet lens design and, when used with the FRA400C, reduces the overall focal length to 280mm and the focal ratio to F3.9. This reducer also provides flat-field correction, enabling full-frame imaging with the FRA400C. The back focus is a standard 55mm.
The shorter focal ratio allows for a wider field of view and faster exposure times, making it ideal for capturing large nebulae, star clusters, and faint or fast-moving celestial objects. The reducer has an M48x0.75 rear-end adapter with a built-in 2-inch filter thread for convenient filter attachment.
Parameters
- (After attaching) FRA400C Focal length: 280mm
- (After attaching) FRA400C Focal ratio: F3.9
- Objective lens: Triplet design
- Back Focus: 55mm (from the base of the M48 male thread)
- Weight: 0.46kg
- Rear-end thread type: M48x0.75 (built-in 2-inch filter adapter)
Installation Instructions
Before proceeding with installation, please read this user's manual carefully.
- Unscrew the four-piece photographic adapter counterclockwise.
- Unscrew the dust cap from the accessory.
- Screw the reducer into the FRA400C.
Diagram Description: The diagram shows the threading specifications of the reducer, including M72x1, M54x0.75, and M48x0.75 with a 2-inch filter thread. It indicates the focal plane and measurements (43.4mm, 4.5mm, 57.4mm, 55mm). The installation steps visually demonstrate unscrewing an adapter and then attaching the reducer.
