Image intensification permits very short sub-exposures of deep space objects, opening up new ways to create high resolution images with high dynamic range. Atmospheric seeing continually shifts and shapes images. Very short exposures of intensified imaging allow for fine reconstruction and editing of the ever changing image. This technique is well known and commonly used for lunar and planetary imaging, where the object is sufficiently bright to be detected by a digital camera in a short exposure.
With sufficient spatial and temporal resolution, an intensified camera is capable of detecting individual photons. The camera operates in the photon counting regime when the photon density per frame is low enough to discriminate individual photons. This is achieved by high frame rates (10-30 FPS) and slow f-ratio (f/24-40). Special processing is applied to photon counting data streams. Each photon in each frame is reduced to a single 1 bit data point then the data points are combined to create the image.
M42 Trapezium area
10” f/16 Classical Cassegrain
ZeroCam 835 sec / 100ms/frame; H-a Filter (10nm)
Photon Counting with frame selection (2377 of 8354)
Core of M13 with 0.5 arcsec resolution
20” Newtonian (Benoit Schillings) at f/20
ZeroCam 213 sec / 30ms/frame
Photon Counting with frame selection (2095 of 7087)
M63 Galaxy
14.5” RCOS
ZeroCam Photon Counting 33ms x 78,000 (43 minutes)
M3
ZeroCam Phton Counting 14.5”
RCOS
M17
Nebula
14.5” RCOS at f/24
Stack of 76,000 frames (20 fps * 1 hour)
M57 Ring
Nebula
14.5” RCOS at f/24
Stack 180,000 frames (31 fps * 1.66 hour)