Sunday, 28 October 2012

Messier 76, Little Dumbbell Nebula

This was my second night out with the Astrosib 250. Although the sky looked very clear during twilight, clouds appeared just when I wanted to start the first exposure. After a short while the clouds luckily disappeared. I run a script (in Nebulosity) to capture light through Ha (7 nm) en OIII filters (8.5 nm), which alternated with each other after each exposure. Exposure times were 20 minutes per subframe. Eventually 5 Ha subs and 6 OIII subs were usable to combine. Other subs were lost during haze and/or clouds and for the simple fact M76 disappeared behind the roof of my house.

Processing was partly done in Photoshop (CS6) and party done in PixInsight. For me it was the first time to really use PixInsight for processing and I liked it. The tools used were deconvolution (Richardson-Lucy, only on M76), AtrousWaveletTransform (noise reduction in the background) and DynamicBackgroundExtraction (slight correction for vignetting).

Shown are the full field of view (slightly cropped), crop at 50% resolution and crop at full resolution.