Milkyway:
Image processing
Image processing is a very important part of making the faint light stand out against the background and getting the most out of image data.
A number of freeware packages are available which enable this data reduction.
The most common procedure is to assemble a number of exposures in to a stack. The exposure time is set depending on conditions e.g. how
long the setup can track without trailing if unguided, or when guiding the optimal exposure time under the sky illumination conditions. The latter
usually amounts to around 5-10 min. under my home skies. For the total stack exposure as long as possible is always a target, I have used up to 10
hours of exposure in order to get good signal to noise ratio with the C8 at F10.
My currently preffered processing routines:
I am now using Astroart 5.0 for image stacking and alignment and some post-processing, which is a great improvement over the freeware options
I have earlier used. For final post processing I use Photoshop Elements 9.0. Both programs are resonably priced. I have not fully experimented
with the capabilities of Astroart 5.0 which has had a lot of new features added with version 5.0 and it's possible that even post processing can
be handled in Astroart 5.0
ST-4000XCM processing:
Image acquisition is performed using CCDSoft version 5.0 which came with the camera, mainly due to its good procedures for setup of multiple
exposures and it's autoguiding functionality. However, I have also not fully experimented with the updated autoguiding and image capture functions
of Astroart and if these work well I would preffer to switch to one application.
Some quick notes on seting up guide star in Carte du Ciel are given below:
Guiding M51.pdf
Processing examples are given below:
M51_24_25_26_27_29Apr11Processing.pdf
Freeware options:
For stacking the exposures (darks, flats and readout frames) i have previously used DeepSkyStacker which is very
effective in performing the stacking and calibration of the frames and for initial tone and color optimization of the final stack image.
Additional image processing e.g. noise reduction and constract enhancements are performed using
WCIF ImageJ and IRIS.
http://www.hennigbuam.de/georg/gimp.html
http://www.gimp.org/
