|
Andrew,
A C8 at 2000mm unguided subs up to 45 seconds are OK with good polar alignment with my Sphinx SXW, provided you can tolerate throwing 20% of the frames. Here is an example of M4 with 15 x 45 second UNGUIDED exposures (with QHY9) reproduced at a scale of 0.5" per pixel.
What Wavytone says about the Sphinx is problably right, but I can't really comment personally on using autoguiding.
Terry
|