| Date 2015/06/19 Observation place My permanent observatory in Longueuil in white light pollution zone |
Technical
| Telescope | Orion 80ED refractor - Diameter 80mm, focal length 480mm, f / 6 |
| Mount | Celestron CGEM |
| Imaging camera | Atik 383 L + monochrome regulated at -20o Celsius |
| Autoguiding camera | ZWO ASI 120MM in parallel with the Orion Mini Guider |
| Auto Guidance Accuracy (RMS) | 2 '' of arc (4 '' of arc in total) |
| Image type | Ha (Ha-OIII-OIII) |
| Exhibition | Ha (10 x 10 'bin 2 × 2), OIII (10 x 10') |
| Image acquisition software | Maxim DL |
| Guidance software | PHD Guiding 2 |
| Pretreatment | Maxim DL |
| Treatment | Photoshop and PixInsight |
Object description
| Object type | Emission nebula |
| Constellation | Little fox |
| Visual magnitude | 15 |
| Distance | 6000 light years |
| Dimension seen from Earth | 40 x 30 arc minutes. Plus the nebulosities around it: about 110 x 100 arc minutes |
| The most striking feature of the NGC6820 nebula is the column (or pillar) that points to the open cluster NGC 6823 which is in the center of the image. The open cluster is about 2 million years old. It is mainly made up of a lot of young and bright stars. Around the cluster there are many other pillars. This set, the pillars and the cluster, represents the NGC6820 nebula. These huge pillars of gas and dust formed when the expanding gas and dust was eroded by radiation from nearby stars. In my picture, the nebula and the cluster are in the center of the picture. I purposely took a larger field of view to include the beautiful dark shades that surround the nebula and the cluster. Due to its visual magnitude of 15, the NGC6820 nebula is very difficult to see in a telescope, even with a large diameter in an environment without light pollution. Also since it is very dark, it is very difficult to photograph. It takes a long exposure time per photo and the integration of several images. To resolve this image in my large light pollution site, I used the Ha narrowband filter (7nm) for the object luminance. The latter made it possible to almost entirely eliminate the light caused by light pollution while allowing the nebula's light signal to pass to more than 95% (because it is entirely in red tones). I also managed to bring out the beautiful nebulosities that surround the nebula (of magnitude over 15!), Which is very astonishing given the extreme light pollution of the site. |
| Richard Beauregard Sky Astro - CCD My impression "We cannot be alone in this gigantic universe" |