Hi, I've been using the comet stacking routine in PI but have encountered a problem when the comet is not on a 'star only' background. Attachments show the two stacked integrations of 'stars' and 'comet'. I've then used PixelMath to combine the two images but while the stars have been removed or greatly reduced when integrating the comet image the nebulosity has not.
Is there a way of removing the nebulosity from the comet integration?
