Sirko Molau provided a 25 mm f/0.85 Fujinon lens for testing with our intensified cameras. I mounted it in front of ICC2 (now called ICC2_25), using a DEP 1700DB intensifier and a fiber-coupled Sony DC-77 CCD camera to it. I performed some flat field measurements on the evening of 20 Aug 2000, since flat field surely is the main concern. See here for images. The conclusion: The lens does not illuminate as well as the 50 mm Rayxar lenses we used before, but they are not extremely bad either. The intensity at the center of the field of view is about a factor of 2 higher than at the edges. To make sure that the image intensifier does not significantly contribute to the uneven illumination of the field, I did some flat fields without any lens, see here. Under a clear night, I used the MetRec detection software to look for meteors. In 4h05m effective observing time, the system detected 28 meteors and about 50 ducks and bats. An example can be found here. The limiting magnitude was about 6.2, the faintest star visible to the naked eye was 5.2. See here for more... For Info: The field of view is 30 deg x 22 deg. In summary, I think this lens is quite good for our intensified cameras. However, for detailed analysis, flat fielding the individual frames is important. Detlef Koschny, 24 Aug 2000. | 
