|
I use a C9.25 and a Losmandy OAG and a Meade DSI II Pro mono for guiding via PHD. A few suggestions (thought my FL is only 2.3 metres compared to yours).
1. Ensure everything is rock solid firm - if even one screw is a bit loose - holding your cameras - you'll get differential flexure and that will spoilt your shots.
2. I had to add a extension tube to bring the DSI II into focus - but it sat a bit loose in the OAG guide tube. I wrapped the DSI II end in sticky tab - a few revolutions, until it was quite snug, and guiding improved dramatically.
3. I focused my main camera using a Bhatinov mask on Antares, then focused the guide camera using Juptier on with the Bhatinov mask. upiter at 5 second exposures was just bright enough to give differaction spikes on PHD so I could focus correctly.
Lastly thought - I am sure you have checked for any gear slipagge - triple check - from every angle. I though my gear was really tight and firm - until CCD Inspector showed the main camera was 7 degrees! tilted - it had slipped and been re-tighten at a slipped position! Differential flexure is probably your main enemy at long focal lenght guiding - so check from every angle in the daylight that your gear on the imaging train is rock solid!
Cheers, Matt
|