Hi everyone.
I'm hoping that someone can ID what looks like a possible issue with field rotation.
Nice clear night, Dark sky site, M16 found & centred, scope polar aligned using PHD drift method as is my usual procedure.
It was cold & dewy, had a dew heater running on the 'Scope - but not the guidescope. Some lens fogging issues noted, hairdryer on standby to clear as required.
http://www.njstargazer.org/PolarAlignment.asp
DY red line was running smooth & flat on Alt & Az on the phd graph as normal. Completed Polar alignment, calibrated and started guiding as usual.
This is a single 10 min sub, dark applied.
Using EQ6, ED120, Orion Miniguidescope, SBIG 8300c OSC
I shot a 5 min sub which looks better, but still not great, also a 7 min sub and it appeared that the longer the exposure was the worse it looked.
I haven't had this happen before, I didn't know you could even get field rotation on a GEM and it's a bit frustrating travelling out to the country and not getting a good return from a long night.
Any helpful input and suggestions are welcome
cheers
Andy