June 20, 2010

Trifid (6-17-10)


The Trifid Nebula, or M20. It is about 5,400 light years away in the constellation Sagittarius. It stands between our Sun and the center of our galaxy, so when we look towards the Trifid, we are looking toward the galactic center. It's a busy place. The Trifid itself is also busy. The red glow comes from ionized hydrogen. The two bright stars in the middle of the red portion excite the hydrogen within the cloud, causing the glow. The blue is reflected starlight. The Trifid is also a stellar nursery. Some of the stars in the image were formed from the very cloud that they now illuminate.

This image was taken with the Orion 6" Inewt and the SXVF-H9C. Flats and bias frames applied. No filter was used, and no coma corrector (I don't have one yet). The image is a stack of 25x8' exposures for a total of 200 minutes. Capture and pre-processing was with Neb 2; color conversion and stacking in Maxim; and touchups in PS3. I have posted two versions, post-processed slightly differently in PS3.

Just for kicks, check out my first image of the Trifid, taken three years ago in June 2007:
This was taken with the DSI Pro, unguided through an Orion 100mm f/6 achromat. I can't remember all the details of the image, but I believe it's about 10 minutes worth of 10-second exposures.

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