NGC2264 is located in the constellation of Monoceros, a little known constellation adjacent to Orion. The designation of NGC 2264 is a little confusing as it is sometimes taken to denote the Cone Nebula (the dark ‘inverted lighthouse beam’ in the upper right of the image) or to the Christmas Tree star cluster, which extends from the cone nebula to the bright star in the centre of the image (15 Mon). Given the extensive nebulosity in this region. my own preference is to refer to the Christmas Tree Nebula for the whole region. The nebula and associated star cluster is located about 2300 light years away and is about 30 light years across.
The image above was taken using Narrow-band filters to isolate the light from Hydrogen, Sulphur and Oxygen gas clouds. I had intended to process this using the SHO colour palette, which assigns Sulphur to the red, Hydrogen to the green and Oxygen to the blue colour channels, however the area is overwhelmingly made up of Hydrogen gas clouds, so the SHO image ended up an unnatural green colour. Part of the problem may have been that the imaging was performed under a partially full moon, which washes out the OIII data in particular. I therefore re-processed the image closer to the ‘true’ colours by assigning Sulphur and Hydrogen to the red channel, and Oxygen to both blue and green. This style of processing can produce odd colour casts to the stars, so I also gathered some shorter RGB data to pick up the correct star colours, and these stars could then be added into the SHO image. Most of the image stacking and processing was performed in Pixinsight, with Photoshop used to bring out the contrast and colours in the final image. Overall, this was a difficult subject to process into an acceptable final image due to the strong hydrogen at the end.
Image Details
- Date: 5th & 6th February 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: 14 x 500s (1hr 57min), OIII: 13 x 500s (1hr 48min) SII: 12 x 500s (1hr 40min), RGB: 10 x 80s (13 min) each filter.
- Total Integration Time: 6hrs.