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 Reducer (for focal length reduction) is an optical accessory that allows a more favourable aperture ratio. Required exposure times are hence shorter and the optics 'faster'. Also, the field of view increases, so that even larger astronomical objects can be observed or photographed.
An essential component of the corrector is an integrated fine adjustment mechanism. By turning the knurled ring on the corrector, you can adjust the distance to the sensor to fractions of a millimetre. Once you have reached the desired distance, fix it with the clamping screw. This allows you to determine the optimum distance with the camera connected by taking test shots without additional adaptors and adjustment rings. The camera does not rotate during fine adjustment.
The following settings from the innermost position of the adjustment to the sensor are recommended:
- Aperture 102 mm / aperture ratio f/7: 55 mm
- Aperture 80 mm / aperture ratio f/7: 57.6 mm
- Opening 80 mm / aperture ratio f/6: 59.6 mm
- Aperture 70 mm / aperture ratio f/6: 61.6 mm
Specific calculation example for the following equipment:
- Telescope: Refractor with 80 mm aperture f/6, i.e. 480 mm focal length.
- Camera: SLR camera with a distance of 55 mm from the M48 thread to the sensor.
Procedure: The working distance is 59.6 mm according to the list above. Simply subtract the 55 mm (distance from the thread to the sensor) from this measurement. This leaves 4.6 mm.
Simply turn the variable adjustment 4.6 mm outwards; this can be easily adjusted using the distance mark. You are now at the optimum distance and can start taking pictures.
TS Optics is a brand of Teleskop-Service.
