What does the 91F 0.75x Reducer do for my Askar 91F telescope?
The 91F 0.75x Reducer shortens your telescope's focal ratio to a faster f/5 and focal length to 455mm. This provides two main benefits: a wider field of view to fit larger objects in the frame, and shorter exposure times to capture faint details more efficiently.
How do I connect the Askar 91F 0.75x Reducer to my camera?
The reducer provides a standard 55mm back focus from the base of its M48 male thread. This is a common standard for most astronomy cameras and DSLRs with the appropriate T-ring. You simply add or remove M48 spacers until the distance from the reducer's flange to your camera sensor is exactly 55mm.
Can I use 2-inch filters with the 91F 0.75x Reducer?
Yes. The reducer has a built-in M48x0.75 female thread on the camera side, allowing you to directly screw in standard 2-inch astronomy filters. This is convenient for using light pollution or narrowband filters without needing a separate filter wheel or drawer.
Is the Askar 91F 0.75x Reducer also a field flattener?
Yes, it is. The triplet optical design is engineered to provide field-flattening correction specifically for the Askar 91F telescope. This ensures that stars remain sharp and round across the entire image, even at the edges of a full-frame sensor.
Which targets benefit most from the 91F 0.75x Reducer?
This reducer is ideal for large deep-sky objects that require a wide field of view. Excellent targets include the North American Nebula (NGC 7000), the Andromeda Galaxy (M31), and large star-forming regions like the Heart and Soul Nebulae (IC 1805 and IC 1848).
When should I *not* use the 91F 0.75x Reducer with my Askar 91F?
You should image without the reducer when your target is small and requires maximum image scale. For example, most galaxies like the Whirlpool Galaxy (M51), smaller planetary nebulae like the Ring Nebula (M57), or any planetary imaging would be better suited to the telescope's native, longer focal length.
