Conditions: aquired from my backyard in light polluted Boulder (Colorado), in January and March, 2004. Reasonable conditions: weak wind, no moon, medium transparency.
Setup: Nikon 180 mm F4; DF-2 focusser; SII, H-alpha, OIII narrowband filters; ST10XE, MaximDL/CCD, Takahashi EM-10 mount (see a mechanical description and view of this setup)
Exposure time: SII: 7x900 sec, H-alpha: 8x900 sec, OIII: 8x1200 sec; Binning: 1x1
Processing (Mira, MaximDL, Registar, Photoshop): dark subtracted, flat fielded, masked hot/cold pixels, de-bloomed, registered, median/avr combined, DDP, color balanced, mild levels/curves, cropped significantly for web format (here's the entire FOV scaled down to fit most monitors)
For the 'natural color' view above I combined the SII (672 nm) and H-alpha (656 nm) exposures for the red channel, while using the OIII (501 nm) exposure for the green and blue channels. In the view below differences in chemical composition have been emphasized by assigning each narrowband exposure to a distinct color channel according to increasing wavelength, i.e. R:SII, G:H-alpha, B:OIII. Which version do you like best? Please let me know!
Here's my main page where you can see more of the pictures I have taken so far.
Comments greatly appreciated! (mikael@leif.org)