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Subject: [M]: PICTOR: Autoguider algorithm
From: Pedro Breda
Reply To: mapug@shore.net
Date: Wed Dec 31 04:43:13 1997


Hi all.

I asked this in APML but havent got any definitive answer yet, so I will try here.
Does anybody know the algorithm used by the 201XT, 208XT and 216XT in the stand-alone autoguiding ?
I mean, when does the guider issues corrections ? only when the guide star change from pixel ?
For example, lets supose a star produces a 120 level (out of 256) in the main pixel, and a 10 level in the adjacent pixel.
If the star moves slightly in direction of the adjacent pixel we may get a 119 main pixel and a 11 adjacent pixel.
Do the Pictors analyse this, or only make corrections when the main pixel changes to other pixel ?
The ST4 I read uses this priciple to get a sensivity of 1/5 pixel.
If the Pictors dont do this in stand-alone mode, do they do it with a PC attached, I mean does the software allos for this ?

I guess the right person to answer this would be Mr. Jonh Hoot, who I believe wrote the Pictor firmware,
but if anyone else knows the answer I would be very thankful.

Thanks in advance.

Pedro Santos
pbs@sistel.cet.pt