Hi. I've been putting my STF-8300 through its paces indoors, getting used to how everything works and I'm seeing artifacts that appear to be in the camera. Attached is an indoor shot at a wall 20 feet away so it's obviously not focused. The artifacts don't seem to change when I rack the focuser from one extreme to the other. The location and appearance of the circles also don't change when I rotate the camera on the telescope, so it's not in the telescope optics. What am I seeing here? Full disclosure: this is the first CCD camera I've owned, so my inexperience may be showing. Thanks. Steve
Those are dust spots. Given their size they are probably on the front window of the camera, or possibly on a filter or focal reducer in front of the camera, if you are using one. There are a couple of things you can do: Get a can of compressed air and blow them off! Use Flat-Field calibration to remove them. That would also help with your vignetting.
Dust! Of course. I'll get a can and do that. A few puffs of air and problem solved! Thanks, Doug! Steve
