What is the optimized image circle for the EdgeHD OTAs and Reducers?
August 25, 2009
The EdgeHD optics are designed to optimize an image circle 21mm in radius from the center of the field of view. Doubling this figure gives an image circle 42mm in diameter. This is big enough to illuminate a 35mm sensor. The OTA's image circle extends well beyond the formats of popular APS-C sensors found on many DSLR cameras and many smaller chips used in specialized astrophotography CCD cameras.
If you are using one of the .7 reducer lenses for either the 1400 or 1100 Edge HD optical tubes, the diameter of the image circle will remain at 42mm. If you are using the .7 reducer lens for the 800 Edge HD the image circle will will shrink to 26.7mm in diameter. The shrunken image circle will fully illuminate a cropped DSLRs (APS-C) senor or smaller CCD.
If you are using one of the .7 reducer lenses for either the 1400 or 1100 Edge HD optical tubes, the diameter of the image circle will remain at 42mm. If you are using the .7 reducer lens for the 800 Edge HD the image circle will will shrink to 26.7mm in diameter. The shrunken image circle will fully illuminate a cropped DSLRs (APS-C) senor or smaller CCD.
