Pat, I have been using APT with my DSLR but didn't even think to try using it with the new Cam86... good thing to know that it will work, thanks. The test image of M42 was a very quick one. The Dobsonian was not properly collimated or cooled (and there was no coma corrector), the focusing was very rough etc. I just wanted to get my first DSO image with the Cam86
Brendan, I did lots of testing of the effect of capacitors.
1. The extra capacitor over R16 did not make any difference. This is weird as it sits directly on pin 16 and it has almost identical distance to pin 12 as compared when it is placed next to pin 9.
2. When I removed one capacitor from our three I did not notice any difference (200uF total capacitance).
3. When I removed another capacitor there was obvious ringing of the vertical stripe (100uF total capacitance).
4. Adding capacitor next to pin 9 solved the problem.
5. Adding back two removed capacitors did not improve anything. I think I will need to cool the sensor to reduce thermal noise before making any conclusions here.
Again the proximity of the capacitor does not clear up the picture completely, as in my point 1 above. The "sweet spot" for C30 seems to be next to pin 9, just like in Grim's and Filip's circuits. Actually placing the capacitor "above" the DD9 and not "to the right of it" would probably make it even better as it is closer to the power pins.
Furthermore, once the stripe was there I could see a definite effect of different power supplies. Perhaps increasing C29 before DD11 (6V regulator) would help stabilise the power even more.
Also, if I was doing the schematics I would place the bypass capacitors next to the actual chip that they are used with instead of next to the power regulators. This will make their function immediately obvious. For example, I think it is slightly misleading to have the bypass capacitor C30 next to power regulator and not next to the actual chip DD11 (in the schematic).