Quote:
Originally Posted by asimov
Stunning image. How did you control the central burnout with all the exposures being @ 3 mins each Bill?
I have an M42 image done with a GSO 8" F4 newt (& 20DA) if you want to see it for comparison sake.
I have been using a 5.5" F3.6 schmidt newt as well & yes, I had to adjust the secondary to get my collimation good. What a pain   |
Because cameras and computer screens have a limited dynamic range (i.e. a limited range of brightness - darkest to brightest) the only way to deal with a burnt out core is to use a technique called Masking (or Compositing). What you must do is overlay the core (a short exposure that is not overexposed) over the top of the longer exposure which has the overexposed core. Basically you are cutting and pasting detail from a short exposure image into the burnt out core of a long exposure image. Software lets you do this in a seamless way. The result is that you have effectively increased the dynamic range in your image. I learnt this technique from Jerry Lodgriguss' excellent website. He and the other top imagers use this method. A few hours time spent touring through his website has saved many folks many nights of error and frustration.
Click here to read Jerry's tutorial on Masking While you're there read through his other stuff, and check out his images. The guy's a legend.