Hi all
Following my posting of the Universe Today article where my Ha image of the Horsehead and flame nebula was featured I thought I would have a go and add the other two emission line filters (OIII and SII) to see what results I would get. It was a very clear night on Tuesday and after doing some imaging earlier in the evening I was ready at about 1.30am to tackle this subject as it had just appeared around the corner of my house. I took 12x10 minute unguided subframes for OIII just in time to do a meridian flip and then 12x10 minutes unguided for SII. I processed these together with the 12 best subframes from the Ha data taken last week. While adjusting the settings in Maxim DL when colour combining I found that using Ha for luminance at 100% and the same Ha data for Red, SII for Green and OIII for Blue with a repective weighting of 2:3:2 for the three channels gave the most pleasing colour blance to my eyes on my monitor (this is probably not he most conventional palette to use but with emission line imaging this doesn't really matter). I saved the result to 16 bit TIFF and then processed in Photoshop CS2. I was quite surprised at the end result because I think I have managed to get the intricate detail that is associated with emission line imaging but at the same time retaining the more subtle colour hues associated with traditional RGB imaging. Only dark subtraction was used using 10x10 minute dark frames median combined that I took earlier in the summer. No flats or autoguiding were used.
Compare this image with the Ha version on my website
http://www.imagingtheheavens.co.uk
As a footnote it was freezing cold, the roads were iced over when I finished and the cars frosted over, the dew heaters did their job perfectly as did my latest purchase, a "Mountain Equipment" down jacket, I was sat outside in the shed virtually all night apart from making the occasional hot drink and I was as warm as toast.
Thanks for looking, a full size high resolution version can be seen on
http://www.pbase.com/imaging_the_heavens
Best wishes and more cold clear skies
Gordon
http://www.imagingtheheavens.co.uk/U...3HaSIIOIII.jpg
im loving the horsehead pics thanks 
