[pvelez (Pete)]

With all the lousy weather in Sydney lately, I have been collecting data from the iTelescope (previously GRAS) service from New Mexico. Its a great system and lets me image in daylight (from Sydney anyway).

I have been collecting LRGB data with a Tak FSQ106 - all very nice.

However, after aligning and combining with Maxim, I find stray coloured pixels. In a dark field, there will be a single red or green pixel (rarely blue for some reason).

The frames are pre-calibrated. iTelescope also supplies the calibration frames and I had a go at calibrating the lights myself - same result.

Clearly there are a few pixels that show up as white in a R or G frame and not in any others. When combined and stretched I have a nasty brightly coloured pixel.

I suspect it is a function of my combine process. I use the Sigma Clip option with 3 passes and a sigma factor of 3.00. I have Ignore Black Pixels and Ignore pixels over 64,999 checked.

Any thoughts on what I am doing wrong?

Pete