I've put the below primary mirror offset compensation calculations in place, and the rig it tracking well! I made a little timelapse with my webcam behind a pair of sunglasses to prevent overexposure outside.
Thursday, December 2, 2010
az = sin-1(sin(off)/cos(e))
em = tan-1(tan(off).tan(e)/(sin(az) + tan(off).cos(az)))
az = additional azimuth angle added by primary mirror
em = required elevation of the primary mirror
off = offset of the primary mirror from centre
e = calculated elevation of the sun
Now the required machine position can be calculated from the elevation and azimuth angles of the sun.
Wednesday, December 1, 2010
I have had a go at this but so far am struggling with the derivation. I assumed that the solid lines were of known length (1 for convenience) but this may not be necessary. If anyone feels inspired please give it a crack and let me know how you get on!