I'm currently investigating the possible causes of Newton Rings in my set-up.
Taking various images etc.
This one (from the 29th) looked interesting:
The disturbance has no AR #, in the red wing various filaments are visible and a filaprom at the edge....
The plate scale was 0.79"/pixel giving a "resolution" on the solar surface of 570 Km/ pixel ( about the size of Tasmania)
To achieve this plate scale with the ED80 and ASI1600 (3.8 micron pixel) the effective focal ratio would be f12.4, this means the x1.6 barlow I use was actually at x1.64.
Onwards and Upwards.
