M16 – The Eagle Nebula

This image is a re-working of my post of 2019 (see here) using the original data but processed with the current improved toolset of PixInsight.

Comparing the two images reveals the superior sharpening and stretching results in the later version. This is especially noticeable in the central ‘Pillars of Creation’ area but also in the wisps of dark nebulosity in the upper part of the image.

As noted previously this is a narrowband image supplemented with Luminosity (clear) data to enhance the detail. SII is mapped to red, H-α to green and OIII to blue, which is known as the Hubble palette but with the three channels balanced so as to prevent the Hα signal from overwhelming the other two.

Initially this palette causes all the stars to take on a magenta colour. To fix this we need either to take RGB data for the stars or, as in this case, make an HOO image from the same data, extract the stars from that and use them to replace those in the SHO. Details of how this is achieved is beyond the scope of this post.

Equipment: Planewave CDK 14″ reflector on 10Micron GM2000 mount. FLI Proline P09000 CCD camera with Astrodon Lum, SII, Hα and OIII filters.

Exposure times: Lum 5 hrs, SII 11.5 hrs, H-α 15 hrs, OIII 12.5 hrs.

Data acquired with ACP Expert/Maxim DL and processed in PixInsight.