Date: 9/12/2010
The month of December is definitely not great for astronomy given the clouds / rain – so I am taking the occasion to process and post shots I took in September in New Mexico,
These two pictures from the Helix nebula were taken with respectively my Canon 200mm Teleobjective, and Takahashi FS-60C, both having very fine optics.
Both were done on my Astrotrac Travel system mount (unguided). Star were slightly elongated because of poor polar alignment, and I tried to fix it as much as possible using Photoshop and techniques described in the excellent book “The New Astro Zone System for Astro Imaging” by R.Wodaski and R.Croman.
Interesting to see the comparison there. Since shots were unguided I was limited to a short exposures especially with the FS-60C. The picture taken with the FS-60C is definitely more detailed – stars are “tight” but colors are not captured as nicely as with the Teleobjective open at f/d 3.5 because of the short sub-frame duration.
Even though more pictures were stacked with the FS60, still the short F/D ratio of the Canon Teleobjective makes the difference when capturing colors from green to yellow to red in this great planetary nebula.
Astrophotography in Urban Environment 