[Marko of Oz (Mark)]

I'm using a DSI-1, colour camera for dso's and when I get an image into Photoshop for post processing the histogram always seems to start blocked all the way to the left rather then a nice bell shape curve that I've seen in tutorials etc.

Is that what's called clipping and am I losing data because of it? If so how do I avoid it, what am I doing wrong if anything?

The first picture shows what I mean about the histogram of a picture that is suppose to be the Pinwheel galaxy M83.
The second picture is the result of some serious curves adjustments.

thanks

Mark