140415

140415 SBAU Telescope Workshop

attendees:  JerryW PaulW TomT TimC DmitriiZ ChrisU

Jerry clarifying difference between pixels & detectors on camera sensors as TomT was questioning why Paul will be getting a mono camera and selling his QHY10 color.  http://www.qhyccd.com/

ccd basics: http://starizona.com/acb/ccd/equipbasicsccd.aspx

Wikipedia on CCDs  https://en.wikipedia.org/wiki/Charge-coupled_device:

"Digital color cameras generally use a Bayer mask over the CCD. Each square of four pixels has one filtered red, one blue, and two green (the human eye is more sensitive to green than either red or blue). The result of this is that luminance information is collected at every pixel, but the color resolution is lower than the luminance resolution.
     Better color separation can be reached by three-CCD devices (3CCD) and a dichroic beam splitter prism, that splits the image into red, green and blue components. Each of the three CCDs is arranged to respond to a particular color. Many professional video camcorders, and some semi-professional camcorders, use this technique, although developments in competing CMOS technology have made CMOS sensors, both with beam-splitters and bayer filters, increasingly popular in high-end video and digital cinema cameras. Another advantage of 3CCD over a Bayer mask device is higher quantum efficiency (and therefore higher light sensitivity for a given aperture size). This is because in a 3CCD device most of the light entering the aperture is captured by a sensor, while a Bayer mask absorbs a high proportion (about 2/3) of the light falling on each CCD pixel."

TomT brought up new Celestron RASA Astrography 11" telescope: http://www.optcorp.com/telescopes/astrograph-telescopes-1/celestron-11-rasa-rowe-ackermann-schmidt-astrograph-ota.html  But some reviewers asked why be limited to a non-visual capable telescope.

Paul showed his photo collage taken during the lunar eclipse late Monday night.

 Dmitrii polishing his 12.5 mirror; Jerry says it needs 3 hours more to smooth it, then pay attention to the surface figuring.

Tim showing star hopping PowerPoint slideshow to Chris and all.  He has some funny cartoon pictures on the charts to make them more memorable.   Tim is also putting time in on grinding the 8" donated mirror, minimizing any concern with the pits left previously.

Chris came by to visit, even though he was under the weather.