[Dennis]

Hi

I’ve been doing an equipment shake down to investigate trailed stars at focal lengths of over 1500mm which begin to become noticeable at exposures of over 3 minutes, and I appear to be having some success.

Last night, I was managing 5 minute sub frames at 1760mm and here is the result of 5 x 5 minute exposures of NGC6369 through the Mewlon 180 with 0.8 FR, giving an efl of 1760mm. ST7E CCD camera, aligned and stacked in MIRA AP with final processing in CS3.

I’m not sure if the apparent “detail” in the ring is a processing artefact or not? At capture, the raw images on screen looked awful; loads of noise and horrible sky glow from Brisbane. The “detail” popped out when I ran the Noel Carboni “Remove Light Pollution” Action in CS3.

Only B&W I'm afraid.

Cheers

Dennis