M42, the Orion Nebula by Răzvan Orbu

M42, the ORION NEBULA or the most photographed deep sky target

Because it is 1500 light years away from Earth, because it is bright and covers a significant area of ​​the sky, this nebula is the target of all those who have ventured into astrophotography. The Orion Nebula is generous, showing itself in both hemispheres, unlike the Carina Nebula which remains faithful to the southern hemisphere.

Essentially, this nebula is a star-forming region. It's the closest to Earth, and because it's so visible and majestic, the ancient Mayans called it the Cosmic Fire of Creation.

The nebula includes an open cluster of young stars, four of which form an asterism called the Trapezium, spanning 1.5 light-years. The four stars emit ultraviolet radiation that affects the star formation process in their vicinity.

But the intensity and scale of the phenomena in the nebula, which is about 25 light-years across, offers the opportunity to study how stars and planetary systems form. Astronomers have observed protoplanetary disks, brown dwarfs, movements of cosmic gases, and studied the photoionizing effect produced by massive stars near the nebula.

M42 can also be seen with the naked eye, it is easy to locate and in the autumn-winter period we can make spectacular exposures and photographs. Having a much brighter center than the rest of the nebula, it is somewhat difficult to present it in its entirety without some effort. The attached photograph is made by processing bright frames that have different exposure times: 10, 45, 60, 90, 120 and 300 seconds. The total integration time is 1 hour and 57 minutes. The camera used is SV605CC, equipped with IMX533 chipset. The sensor size allows the complete framing of the target. The bright frames were taken with a dual band filter that allows only the Ha and OIII bands to pass.

The processing was done in Pixinsight, where the queens of the workflow were HDR Composition and HDR Multiscale Transformation (to highlight the Trapezium formation). I chose to separate the color channels and recombine them in PixelMath in HOO mode. The color masks in combination with the Curves Transformation process defined the presented image.

Text and photo author: Răzvan Orbu , Astroclubul Bucharest, Romania