| Date 2018/08/16 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 with one optical splitter |
| Auto Guidance Accuracy (RMS) | 0,91 '' of arc RMS (1,82 '' of arc in total) |
| Image type | Ha (Ha-OIII-OIII) |
| Exhibition | Ha (10 x 10 'bin 2 × 2), OIII (10 x 10' Bin 2 × 2) |
| Image acquisition software | Maxim DL |
| Guidance software | PHD Guiding 2 |
| Pretreatment | Maxim DL |
| Treatment | Photoshop and PixInsight |
Object description
| Object type | Emission nebula and open cluster "The Heart nebula" |
| Constellation | Cassiopeia |
| Visual magnitude | 6,5 |
| Distance | 7500 light years |
| Dimension seen from Earth | 190 x 155 arc minutes |
| The large, faint Heart Nebula is made up of hydrogen gas ionized by ultraviolet radiation from hot young stars. It contains, in its center, the dense open cluster IC1805. The nebula, nicknamed the Heart Nebula, is much larger than the open cluster, which is confusing. Indeed, the Heart nebula has a dimension of approximately 190 'by 155', while the open cluster (which is referred to as the heart nebula) covers 60 'by 60'. Before photographing this nebula, it is imperative to take this fact into account, because, if we trust the official dimension, we will take a single small portion of the Heart nebula. The Heart nebula encompasses several objects listed in astronomical catalogs. In addition to the dense open cluster IC1805, we see, at the bottom right, the nebula IC1795 (NGC896) that I photographed on October 9, 2012 in a site without light pollution. We can also see the open cluster MK6 to the left of the nebula, slightly downwards. There are also other objects inside the Heart nebula. Unlike the bright open cluster IC1805 of magnitude 6,5, the nebula is much less so that it is hardly visible in a telescope, even a large one. To see the Heart nebula properly in a long exposure photograph, it is imperative to use an H-Alpha luminance image which will bring out the hydrogen gases that make up most of the radiation from this nebula. Without the use of this filter, the nebula will remain inconspicuous and will be obstructed by the large number of stars that compose it. This H-Alpha filter also has the particularity of effectively combating light pollution. In my image, it is still astonishing to have managed to get so many details and depth of the nebula in my site of extreme light pollution (Longueuil in the suburbs of Montreal, Quebec, Canada which is an area of white light pollution ). |
| Richard Beauregard Sky Astro - CCD My impression "We cannot be alone in this gigantic universe" |