This is a result from last night with my cooled DSI II camera.
It represents tracking for 52 minutes on the same field at 1524mm FL.
Approx 12 cycles of the worm.
No guiding or corrections done during this 52mins.
The FOV is approx 14 arc mins x 11 arc mins.
Every frame of 500 frames was used in the stack to get the result.
Seeing was very good.
The align file was loaded into Excel and correction for sky rate error
applied using Sheeny and Mithrandir's previous suggestions.
This makes the sine wave trendline flat and shows the drift of PE
better. Green is before correction, red is after.
Just over +/- 5 pixels drift over 52mins unguided.
At 1.14 arc seconds per pixel that would be around +/-6 arc sec drift.
A happy chappy
Steve
PS:
Note the fuzzy in the neg shot....still trying to identify what it is .....