The Soul Nebula (IC1848) is a large emission nebula located in the constellation of Cassiopeia. It is close to the Heart nebula, which has given rise to the naming of the pair as the Heart and Soul Nebula. The nebula lies at a distance of 7500 light-years from Earth and is about 165 light-years across. It was discovered photographically in 1910 by the American astronomer Edward Emerson Barnard, and included in the Second Index Catalogue by John Louis Emil Dreyer as IC1848.
The image above has been taken using narrowband SHO filters to record the concentrations of Sulphur, Hydrogen and Oxygen elements, with each narrow-band image being assigned to an RGB colour . The nebula is mostly hydrogen, but the colour channels have neem balanced to avoid the hydrogen from dominating the image. This technique then shows that the centre areas of the nebula contain a higher proportion of oxygen, which shows up as the blue colours in the image.
During early April in 2025, there was an unusually long spell of clear weather in the UK, which allowed me to gather data over a period of 10 nights, giving a total exposure time of over 46 hours. I decided to concentrate on a single target to see how much difference this extended exposure time would make in teasing out the faint nebula details. My conclusion was that extended time certainly gave more detail, but after around 20 hours, the differences were becoming marginal. Given the generally cloudy conditions in the UK, 20 hours would therefore be a sensible target exposure time to aim for in future.
Image Details
- Date: 1st to 12th April 2025.
- Telescope: Altair Astro 72EDF +0.8 Focal Reducer. Focal Length: 345mm, Aperture: F4.8.
- Camera: Altair Astro 183MM Cooled Mono Astro Camera. Offset 40, Temp -10degC. Gain 400 for SHO data, Gain 200 for RGB stars.
- Filters: H-alpha – Baader 7nm 2 inch filter. OIII – Baader 8.5nm 2 inch filter. SII – Antlia 3.5nm 2 inch filter. RGB – Optolong RGB Filters.
- Mount: Skywatcher HEQ5.
- Guide Scope: Altair Astro 60mm.
- Guide Camera: ZWO ASI 220MM Mono guide camera.
- Exposure Details: Ha: 85 x 500s (11hr 48min), OIII: 120 x 500s (16hr 40min) SII: 111 x 500s (15hr 25min), RGB: 35 x 80s (47 min) each filter.
- Total Integration Time: 46hrs 13min.