The night is still young and although Orion is heading west Leo is lining up towards the south. This is constellation with several bright galaxies. The 80mm APO I am using has a reasonably large field of view and can capture three of these galaxies in a single frame. This is quite a common group of galaxies for Astro-photographers and hence the name Leo Triplet.
Another small problem is showing up. Hot pixels. Nearly every CCD camera has a few (or many) hot pixels that show up as one of the primary colours (red, blue or green). Now I am getting a bit too clever for my boots as my tracking skills are improving. Problem now is that a hot pixel will appear in each stub at the same place. With accurate guiding the target is in the same place on each frame and hence so are the hot pixels. Taking an average of many frames will not remove such hot pixels. The technique is to use dithering. This means the camera must be very slightly shifted between frames. When the images are aligned on the target the hot pixels will be in a different place each time and will thus have little or no consequence on the final image when averaged.
So we see it is a continuous learning curve!
