For the use of large CCD cameras, we
have developed a precisely calculated 4" field corrector for our RC telescopes.
The corrector eliminates the maximum design field curvature and astigmatism
up to the edge of the field. With the AFFC you get a flush, coma- and astigmatism-free
field of free of vignetting which is 65mm diameter. The picture is much
better than sight alone would allow.
|Alluna Flat Field Corrector
The stars are point-like to the edge
of the image field. The two lenses have a diameter of 94 mm, the free clearance
is 92 mm, the coating of all surfaces is 400-900 nm. The focal length is
extended slightly from f/8.0 to f/8.1. Spectral bandwidth is optimized
to 404 - 1050 nm. The connection is an M100x1 and fits on all our Alluna
||For example, the CCD
sensor Kodak KAF-16803 sensor with 36,8x36,8 mm and a diagonal of 52.1
mm adjusts easily to the usable field . Sensors with 45x45 mm / 64 mm diagonal
can be used.
For the use of sensors for fields
larger than 65 mm, this is only conditionally recommended. The vignetting
increases considerably. For such special cases we can offer special correctors
and adjust the telescope with a modified baffle system to an even bigger
Flat Field Corrector AFFC
Our RC Reducer, which corrects the maximum
design error field curvature and astigmatism at the same time, reduces
the focal length from f/8.0 to f/6.0. The usable field of view is 60 mm,
optimized compensation of all surfaces 400-700 nm. The reducer fits with
the M100x1 seamlessly connecting with all of our RC telescopes.
| Alluna Flat Field
Reducer AFFR 0,74x
| Differences in the
image of the AFFC to the AFFR
||With the example of the
galaxy M51, you can see the difference in the image.
- photo above with AFFR Reducer
- photo below with AFFC
Please note only the size in the
left photo since both images have different exposure time.
Photo with RC20 inch
example from the globular cluster M22 in Sagittarius is clearer because
the RC-Reducer was used allowing .74x about 25% greater image detail. In
addition, the exposure time is reduced correspondingly.