I was inspired by Vincent re-processing his images during stormy night and coming up with beautiful Jupiter photos. When electricity was restored, I reviewed my images taken before and found out that the flat frames taken for the
Blue Horsehead image exhibit severe vignetting and uneven illumination. No wonder I had difficulty processing this nebula. I took another set of flat frames but this time I used the computer screen as "light box". My regular light
box was designed for my scope and not for the zoom lens which somehow resulted in faulty flat frames. I soon discovered that the heavy sky glow gradient was reduced which made processing a lot easier. Color balancing was also not too
difficult as before. Good flat frames do really help.
Here again is a re-processed image of IC 4592, a large faint reflection nebula
in Scorpious taken with a 70-300mm zoom lens:
