On 1/6/09, Joseph McAllister, discombobulated, unleashed: >This discussion has triggered my earliest digital camera memories, >back when TV studios were still using tubes to image. > >My camera was about the size of the Hubble, flew in orbits between 250 >and 175 miles depending on requirements, and could image items on >earth as small as 40 inches (one meter +). In 1976. By the time I left >the project in 1987, it could image items as small as a loaf of sliced >American bread. Some said as small as a golf ball, but that's a >contrast thing, not resolution. You could tell if someone had a hat or >helmet on, and if their shirt was long sleeved or short. > >The sensor consisted of three overlapping strips of CCD sensor about >2" long and 1/4 inch wide. > _________________ > ______________ _____________ > >Like that. They could image either in "still mode" or "strip mode". In >either case they were capturing the image as it crossed the sensors >and the satellite cruised by overhead. In strip mode you could take in >a 10 to 60 mile wide area (vertical or oblique) by as long as you >wanted. The bird was stabilized and pointed (positioned) quite rapidly >if need be by a series of Control Motion Gyros (CMG) that had brakes >on each. CMGs were spinning rapidly, and to reposition the satellite >the brakes were applied to one or more of the CMGs for a bit to start >the motion, then again to the opposite CMG to stop it. Six CMGs were >employed, in various orientations, though I believe three were >primary, and the other three were cut in as backups if one of the >primaries failed. Because it was in space, and weightless, it didn't >take as much energy as you think, but you were starting and stopping >several tons, and the laws of inertia still applied. > >The latest generations are still up there, so always smile and wave >when you look up at the clouds
Joseph that was a fascinating read, thanks mate. -- Cheers, Cotty (sat in Terminal B near Gate 67 waiting for the 9pm redeye to London) ___/\__ || (O) | People, Places, Pastiche ||=====| http://www.cottysnaps.com _____________________________ -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
