Askar 1x Field Flattener for 120APO
- Designed specifically for the Askar 120APO Telescope
- 1x Magnification Factor
- Triplet Optical Design
- Maintains Native f/7 Focal Ratio
- Standard 55mm Back Focus
- Weighs 0.75kg
The Askar 1x Field Flattener for the 120APO is a dedicated triplet corrector that maintains the telescope's native 840mm focal length and f/7 focal ratio. It establishes a standard 55mm back focus from its M48 male thread, ensuring compatibility with common imaging trains. Weighing 0.75kg, it provides robust optical correction without significantly altering the instrument's balance.
This 1x flattener is engineered specifically for the Askar 120APO, using a triplet optical design to eliminate field curvature and coma across large imaging sensors. By maintaining the telescope's native f/7 focal ratio, it prevents any change in image scale or exposure times. The result is a perfectly flat field, rendering stars as sharp points from the center to the corners of a full-frame sensor.
Integration into your imaging train is straightforward, with a standard 55mm back focus measured from the base of the M48 male thread. The camera side includes both M54x0.75 and M48x0.75 adapters, and the M48 adapter features internal threads for 2-inch filters, allowing you to add light pollution or narrowband filters without extra spacers. The entire 0.75kg housing is CNC-machined for precise alignment and includes threaded metal caps for protection.
No. As a 1x flattener, it is designed to maintain the Askar 120APO's native 840mm focal length and f/7 focal ratio. It corrects for field curvature without altering the image scale.
The required back focus is a standard 55mm, measured from the base of the male M48x0.75 thread on the included adapter. This simplifies connecting most DSLRs (with a T-ring) and dedicated astronomy cameras with filter wheels.
The flattener comes with an M48 adapter that has internal M48x0.75 threads. You can screw a standard 2-inch mounted filter directly into this adapter before attaching your camera.
Yes, this flattener is designed to fully illuminate and correct the field for full-frame sensors. When paired with the Askar 120APO's 840mm focal length, it provides an ideal image scale for large targets like the Andromeda Galaxy (M31) or the North America Nebula (NGC 7000), ensuring sharp stars across the entire frame.
The flattener provides two connection options on the camera side: a native M54×0.75 thread and an included adapter to step down to a standard M48×0.75 male thread for connecting most imaging equipment.
With a weight of 0.75kg, the flattener will add some weight to the back of the telescope. You will likely need to re-balance your 120APO on its mount, especially after adding a camera and other accessories, to ensure accurate tracking.
| Optical Design | Triplet (3-element) |
| Magnification | 1x |
| Compatible Telescope | Askar 120APO |
| Focal Length (with 120APO) | 840mm |
| Focal Ratio (with 120APO) | f/7 |
| Back Focus | 55mm (from M48 thread base) |
| Camera-Side Threads | M54x0.75 & M48x0.75 (via adapter) |
| Filter Threads | M48x0.75 (2-inch) inside M48 adapter |
| Weight | 0.75 kg |