The flattener is a lens that evens out the field, as this is slightly curved by the primary optics. This curvature causes stars that are imaged at the edge of the field of view to be less sharp. The flattener, also called a field flattener, corrects this effect. Astrophotographers can then enjoy images where the stars remain sharp right out to the edge of the exposure. The flattener is installed between the telescope and the camera.
The corrector is optimised for refractors with a focal length of 900 mm or more. However, it can also be used on refractors with a shorter focal length. The working distance must then be extended accordingly.
Working distances from the M48x0.75 external thread:
- Refractors with a focal length of 900 mm or more: 55 mm from the M48 thread
- Refractors with a focal length of 800-900 mm: 57 mm from the M48 thread
- Refractors with a focal length of 700-800 mm: 59 mm from the M48 thread
The corrector has two additional threads for individual adaptations:
- M78x1 internal thread: The working distance increases by 22.5 mm – enough space to install an off-axis guider.
- M54x0.75 internal thread: The working distance increases by 7.5 mm – ideal for full-frame cameras if you want to avoid the M48x0.75 bottleneck.
The corrector requires at least a 2.5" focuser. An M92x1 external thread is available on the telescope side.
TS Optics is a brand of Teleskop-Service.
