Anyone who is involved in astrophotography will inevitably stumble upon the term: Flatfield . If a picture is taken by the telescope, image errors occur which result from the differently strong illumination of the sensor. In order for the image processing software to correct this error, pictures of a uniformly illuminated area are required, which are created under the same conditions as the actual images. The Aurora Flatfield phosphor film creates such a surface.
The advantages of the Aurora Flatfield light films:
- Completely uniform illumination of the lens opening
- Complete spectrum, therefore can also be used in combination with line filters
- Power supply for 12V or mains voltage available
The Aurora flatfield foils are delivered fully assembled in a plastic frame: The frame is made of unbreakable plastic, has rounded corners and is covered with an edge protector: Your Aurora foil is perfectly protected during transport to the observation site, and the milky front plate ensures an even smoother finish Brightness distribution.
The diameters of the foils are chosen so that the typical instrument sizes are well covered:
- Diameter 100mm for devices up to 4 "opening
- Diameter 160mm for devices up to 6 "opening
- Diameter 220mm for devices up to 8 "opening
- Diameter 315mm for devices up to 12 "opening
- Diameter 420mm for devices up to 16 "opening
- Diameter 590mm
- Diameter 750mm
Choosing the right size:
- To get high quality flatfield data, the free opening of your instrument must be completely covered. The diameter of the dew cap or similar is not crucial! As an example: For a 6 "(15cm) refractor, the 160mm Aurora is sufficient, regardless of the diameter of the dew cap!
- If you use a Newton, RC, ODK or similar, the Aurora luminescent film must be larger than the free diameter of the optics! As a rule of thumb for a Newton: Free mirror diameter + diagonal of the sensor of your camera. Here is another example: For an 8 "Newtonian, a 220 Aurora is sufficient if you use a camera with a very small chip (<14mm diagonal). If you use a typical DSLR with APS-C sensor, you have to choose a 315mm Aurora.
It is easily possible to use a large Aurora for smaller instruments: If you have a 315mm Aurora, for example, you can use it for a 4 "refractor or your camera lenses without any restrictions.
The brightness of the foils is ideal for recordings with filters , but it must be reduced for recordings in white light or only with an L filter. The brightness of the Aurora Flatfield light foils can be regulated within limits by reducing the input voltage (only when using 12V inverters). In addition, the brightness can be realized simply and inexpensively by placing one or two layers of white paper in the frame between the film and the instrument! For use on very bright devices or for large cameras with slow shutter you will find gray film filters in the appropriate sizes under "Recommended accessories". With these foils a very strong reduction in brightness is possible. For use on bright astrographs, we recommend ordering these foils directly!
The power supply : There is an associated inverter for every size of the Aurora Flatfield luminescent film. A normal power supply unit cannot be used because the luminescent foils are operated with high voltage. Due to the low current, there is no danger! Please only use the foils with the recommended inverter: They also shine with larger inverters, but their lifespan is greatly reduced as a result!
Scope of delivery: Aurora Flatfield light films are supplied as a completely ready-to-use set. This consists of the luminescent film in the frame, the appropriate inverter, all necessary cables and a printed operating manual.