NGC 7023 – The Iris Nebula

This is NGC 7023, also known as the Iris Nebula and Caldwell 4. Actually, the nomenclature is a bit more complicated than that. The designation ‘NGC 7023’ refers not to the nebula, but to the open cluster concentrated in the dark area to the right of the nebula’s central star. The Iris Nebula is catalogued as LBN 487. It is primarily a reflection nebula, with the the blue hues coming from light reflected off soot/dust around the bright star. There are also some subtle pink structures that are due to H-alpha emissions.

The Iris Nebula is within our own Milky Way galaxy, about 1,300 light years from Earth. It has a diameter of about 6 light years and covers a little more than half the Moon’s width on the sky, at about 18′ across. However, the brown dust extends much further. The bright star at the centre of the nebula is called HD 200775 and is easily visible in binoculars, but I have found the nebula very challenging to see visually. I have imaged the Iris Nebula region many times over the years, but this is the closest and deepest shot so far.

Tekkies:
Acquisition, focusing, and control of Paramount MX mount with N.I.N.A., TheSkyX. Guiding with PHD2. Primalucelab low-profile 2″ Essato focuser, ARCO rotator and Giotto flat panel. Equipment control with PrimaLuce Labs Eagle 4 Pro computer. All pre-processing and processing in PixInsight. Acquired from my SkyShed in Guelph. Data acquired under moderate to no moonlight, good transparency and average seeing September 29 – October 5, 2024.

Celestron 14″ EDGE HD telescope at f/11 (3,940 mm focal length) and QHY600M camera binned 2×2 with Optolong filters.

54 x 5m Red = 4hr 30m
55 x 5m Green = 4hr 35m
48 x 5m Blue = 4hr 00m
32 x 5m Lum = 2hr40m

Total: 15hr 45m
Image scale 0.4 arcsec per pixel

Copyright: Ron Brecher