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Originally Posted by Moon
In that attached image the OSC index is 0.06.
In my view that means only one thing - you were trying to guide off a hot pixel, not a star. It would explain your symptons as well.
James
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This is what PHD help file has to say about OSC...
Quote:
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In the lower-left of the graph, an "oscilliation index" is shown. This is the result of calculating (in the current window's worth of data), the odds that the current RA move is in the opposite direction as the last RA move. If you are too aggressive in your guiding and over-shooting the mark each time, this number will head towards 1.0. If you were perfect and not over- or under-shooting and your mount had no periodic error, the score would be 0.5. Perfect with periodic error and the score may be closer to 0.3. If this score gets very low (e.g., 0.1), you may want to increase the RA aggressiveness (and/or decrease the hysteresis). If it gets quite high (e.g., 0.8), you may want to decrease the RA aggressiveness (and/or increase the hysteresis).
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so I am not sure that 0.06 is such a good thing after all....
Guiding off a hot pixel has happened to me before and you just get a flat line graph in DEC and RA - which makes sense. THe hot pixel doesn't move at all, so no corrections are required to keep it in the same spot.
Adam