Challenge: Free Study 2008-03 (Advanced Editing VII)
Camera: Canon EOS-350D Rebel XT
Location: Bedford, NH
Date: Mar 11, 2008
Date Uploaded: Mar 9, 2008
|I am certainly enjoying my new toy (telescope)! This photograph is peering into the center of the Rosette nebula, a HUGE star forming region that's about 6x the width of the full moon! Unfortunately, it is so extraordinarily dim that you can't view it in a telescope, it's only viewable through long exposure photography. The color is true, the rosette has a somewhat purple hue to it because it's two dominant wavelengths are hydrogen alpha (red) and doubly ionized oxygen (teal).
Now about the photograph.
Telescope: Anttler's optics 10" reflector
Camera: Modified Canon 350xt
Mount: Losmandy G11
Filters: Hutech IDAS (light pollution), Baader Hydrogen Alpha
Camera settings: ISO800, noise reduction on, Bulb
Registration: All images are aligned to a single "base" image using Registar
This is a composite of 10 exposures, 4 of the exposures are 10 minutes each and taken with a Baader Hydrogen Alpha filter, the red channel was cut and pasted to the green and blue channels making a greyscale RGB. This image is used as a luminance channel in the final image. The RGB image is a composite of 6 8 minute exposures taken with a Hutech light suppressant filter (for overcoming light pollution) and stacked and flattened in photoshop. The red channel of the RGB image and the greyscale luminance image were combined and flattened (50/50) and pasted back into the red channel. The 50/50 channel is the new luminance layer. Curves, saturation and contrast applied to both the luminance and RGB images and flattened.
While all this sounds somewhat daunting, using the luminance layer is the best way to deal with light pollution and I do all this work with actions, so post processing is a snap.
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