I made an error here, but did it correctly a year or two ago: The reflected conc-panel-2nd conc. is ALWAYS back to the Sun, if the two concentrators have equal angles to the panel (irrespective of concentrator angle), and Sun is at 90 degrees angle to the panel. However, if the concentrators are wide enough (and the angle is 60 degrees and panels pointed to the Sun) a reflection conc-2nd conc will be 60 degrees off the anti-sun direction. (A pointing error of x degrees gives 60-2x degrees). Observations by Ed Cannon and others of flares 3-4 hours before or after (anti-sun or shadow entry/exit?) seemed to confirm this. However, I didn't realize until today that this simple analysis assumed that Sun and normals of panel and concentrators are in one plane. And the conclusion on time offset requires that panels and concentrators are oriented parallell to Earth's polar axis. If they are in the equatorial plane, the offset would be only in declination (except for pointing errors). If the panels are oriented somewhere in-between the polar axis and the equator there would be partial offsets to both RA and Dec of reflection, which would explain both Kevin's off-season obs, and different time offsets. Of course it is easy to calculate a conc-conc reflection for any given angle, orientation, pointing error and solar declination, but there would be no useful pattern unless the angle and orientation is known, and steady, and the pointing errors very small. /Björn Kevin replied privately: > So far I find that the Boeing HS702 with the solar concentrators appear to flare when they are 12 > hours away from the sun, compared to the Boeing HS702 that don't have the solar concentrators. > > And this was away from the equinox, such as my obs at > http://www.satobs.org/seesat/Feb-2006/0060.html > ... > The PAS 1R obs was around 2:32 UTC ( Oct 22 ) I couldn't dectect PAS 6B > and PAS 3R which I had before, when the sun was at the right DEC. ... ----- Original Message ----- From: "Björn Gimle" > > I (may) have seen info that the solar concentrators are inclined +-60 > degrees off the panels themselves. > > In that case, flares would be seen +-60 degrees from the anti-sun RA, > reflected conc-panel-2nd conc. > > When or where was your obs made? > (Including that detail should be almost self-evident in a satobs > post!) > ... ------------------------------------------------------------------------- Subscribe/Unsubscribe info, Frequently Asked Questions, SeeSat-L archive: http://www.satobs.org/seesat/seesatindex.html
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