Larry Pfeffer
JC Reddy
George Toye
Joe Wagner
The first one with effective focal length of 116mm preferred. However, it is suggested that we go for full 100mm diameter for the primary mirror (maximum possible). Accepted by the group. See below for additional changes.
Clearly, there is not enough place there since the total distance available in front of the primary mirror is only 2 inches (~50mm) - according to the current gimbal design (can be increased - but it would increase the overall size, may not be acceptable).
Sam Drake suggested beam splitters a while ago. However people were skeptical about what % of light will be lost if a beam splitter is used. CCD camera will be used in the back of the primary mirror as shown in the figure if the beam splitter is acceptable. There is a plenty of room in there.
Joe and Larry have done some experiments to see if beam splitters are ok. Qualitatively the losses are "not too much" (less than 10%), and image quality on the CCD seems ok. However, some additional questions were raised:
Preliminary calculations by moving PSD by 25 mm back, keeping the effective focal length about 120 mm, and changing the curvatures of mirrors show that it might be - but we incur more light losses because of the blockage due to secondary mirror - about 22%; should be reduced.
He also made available on the web three new catalog pages detailing video camera options. The current favorite configurations are using the PC-9XS camera alone--utilizing and a beam spliter and the seeker mirror to provide a 5 degree field of view, or the ML-12MM lens for a 18.4 degree field of view.
Finally future plans and logistics were discussed.
Optics worked out ASAP. 7/13: Check on I/O board 7/20: hook PSD into computer 8/1: Stuff ready to send to Sam 8/8: full set up for control 8/15: final working seeker 8/24: sending for demo