Group of French amateur astronomers, named Ciel Boreal (when imaging under northern skies) or Ciel Austral (when presenting images from their observatory located in Chile), is well know for top-quality images of deep sky objects. And we are proud Laurent Bourgon, Jean-Claude Canonne, Nicolas Outters, Philippe Bernhard and Didier Chaplain use G4-16000 cameras with all their telescopes.

This time the group installed a 50 cm CDK (Corrected Dall-Kircham) telescope with 340 cm focal length at their observatory in Chile. The “first light” was the M83 galaxy, also known as the “Southern Pinwheel”. Total exposure time was 25 hours, which is pretty incredible, but sill this exposure time falls short compared to hundreds of hours needed to capture narrow-band images of various nebulae.

The image is composed from individual frames taken through red, green and blue filters, providing color information, and image taken without filter, which is used for luminance. What's more, another long exposure image, taken through Hα filter is used to emphasize the deep red hydrogen clouds in the galaxy.

For more details, visit the author's web site www.cielaustral.com.