The all-sky imagers that use the electron multiplication CCD technology
are manufactured by Keo Scientific. Each imager has
telecentric and non-vignetting optics, and the field of view of the
fish-eye lens is 180 degrees. A mechanical shutter protects the filters and CCD
from direct sunlight. The filter wheel can accomodate eight narrow bandwidth interference filters. One filter holder is left "free" to be able to acquire nonfiltered images. Every station has six filters: green, blue, red, and a background filter for each colour.
The signal-to-noise ratio and the dynamic range of this system are much
higher compared to the previous generation devices. The imaging mode
consists of three bursts of green images, two bursts of blue images, one red one,
one filtered one, and one of each background images within one minute. The data
are stored in 16-bit png files.
Photo: Jyrki Mattanen
| ITEM | DESCRIPTION |
| Fish-eye lens | Mamiya Sekor 24mm f/4 |
| Additional optics | Telecentric lens elements |
| Filter wheel | 8-position filter wheel for 3" filters |
| Filters | Wavelengths 427.8nm, 438.0nm, 540.0nm, 557.7nm, 620.0nm, 630.0nm (BW 2.0nm) |
| Re-imaging optics | Schneider Optics Inc. Century Achromatic Diopter +3.5 |
| CCD camera lens | Canon 50mm f/0.95 |
| CCD camera | Andor iXonEM + DU-888 (1024x1024 pixels) |