M 42 (EN)

Emission Nebula in Orion
R.A.Dec.SizeMag SBCnt.StTypeDistanceChart
05h 35m 16.4s-05° 23′ 35.9″1.5°4.013.1EN+RN; 3, 2, 3EN----
M 42 DSS plate
Source: POSS-2 UK Schmidt Red (STScI) | Field: 60′ × 60′

Background

M42 is the Orion Nebula — the closest large star-forming region to Earth at  1,350 light-years, and one of the brightest nebulae in the sky. Naked-eye visible; the central Trapezium cluster of hot O-type stars ionises the surrounding gas. The richness of detail across all apertures makes it the most-observed deep-sky object of all.

My Observing Notes

44-cm (Club 17.5-inch f/5): Centred almost on impulse as Orion cleared the eastern horizon. With the 31 mm low-power eyepiece, the combination of low magnification and the Club scope's aperture gave the nebula a sense of depth I had never seen before. It has been many years since I last looked through a large aperture, and I had forgotten how spectacular the views can be.(Saturday, September 2025)

References

Charts

M 42 ultra-wide chart
Ultra-wide view (~25° field)
M 42 wide-field chart
Wide-field view with Telrad rings (4°, 2°, 0.5°)
M 42 finderscope view
Finderscope view (9×50 RACI, ~4.4° TFOV)
M 42 eyepiece view
Eyepiece view — 35 mm Panoptic on 12-inch f/5 (1.6° TFOV)