The Horsehead Nebula, the Flame Nebula, and IC 434
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Winter may not be everyone’s favorite season, but it is undoubtedly a time when we can admire some of the most beautiful constellations. One of them is Orion (Orion), which contains numerous breathtaking deep-sky objects.
The constellation of Orion was named and placed in the sky by the ancient Greeks. In their mythology, Orion was the son of the sea god Poseidon and Euryale, one of the Gorgons, making him the nephew of the infamous Medusa with her snake-like hair. Orion was celebrated as the greatest hunter ever to walk the Earth, capable of moving silently and even walking on water. He fell in love with the Pleiades, whom he still chases across the sky to this day. According to legend, he died from the sting of a scorpion sent by the goddess Artemis. Since then, the constellations of Orion and Scorpius have been placed on opposite sides of the celestial sphere. Even Orion’s faithful hunting dogs, Sirius and Procyon, were set in the heavens as the brightest stars of the constellations Canis Major and Canis Minor, respectively.
Interestingly, in the case of this constellation, Alpha Orionis (α Ori) is not the brightest star. That distinction belongs to Beta Orionis (β Ori), also known as Rigel. Alpha Orionis, or Betelgeuse, ranks second in brightness. Located about 600 light years from Earth, Betelgeuse is classified as a red supergiant. If it were placed in the position of our Sun, its surface would extend roughly to the orbit of Jupiter. Its reddish hue stands out among the surrounding stars, and it is believed to be nearing the end of its life cycle, eventually destined to explode as a supernova. Near Betelgeuse, at the position representing Orion’s other shoulder, lies Gamma Orionis (γ Ori), known as Bellatrix. Lambda Orionis (λ Ori) is a fascinating multiple star system with several gravitationally bound components. South of Betelgeuse and Bellatrix lie three bright stars that form Orion’s Belt: Delta (δ), Epsilon (ε), and Zeta Orionis (ζ Ori), known as Mintaka, Alnilam, and Alnitak, respectively. Between Orion’s Belt and the stars Rigel and Saiph (κ Ori) lies Orion’s Sword, which contains the Orion Nebula, visible even through binoculars.
In addition to the Orion Nebula, several other fascinating deep-sky objects lie within the boundaries of this constellation. In Photo 1, I have marked the rectangular region where the nebulae discussed later in this article can be found.
Observations
January 31, 2019, around 10:30 PM – Zaborze (Poland)
Suburban conditions, moderate light pollution
The cool night and clear sky encouraged me to set up my equipment for observation. I managed to capture several dozen minutes of exposure, which, after proper processing, produced the photograph shown below.
The photograph shows the region of Orion’s Belt, featuring two of its main stars: Alnilam and Alnitak. Both are blue supergiants located about 1,300 light years from Earth, with Alnitak being slightly closer. Alnitak is a triple star system composed of ζ Ori B (the more distant component) and two closely bound stars, ζ Ori Aa (the primary Alnitak) and ζ Ori Ab. Also visible is Sigma Orionis (σ Ori), a quintuple star system approximately 1,150 light years away. Near Alnitak lie at least four remarkably beautiful and intriguing nebulae.
The first of these is NGC 2024, also known as the Flame Nebula. It is an emission nebula and an H II region located about 1,500 light years from Earth. Discovered by William Herschel on January 1, 1786, the nebula resembles a flame and has an angular diameter of about 0.5°. In visible light, the Flame Nebula appears reddish due to the recombination of hydrogen atoms. Its ultraviolet radiation, responsible for ionizing the gas, most likely comes from a young star embedded within a cluster of hot stars visible in infrared wavelengths. This cluster is obscured by a dark band of dust that absorbs visible light, creating the nebula’s characteristic silhouette.
IC 434 is similar to the Flame Nebula in many respects, also glowing red because of its hydrogen content. However, it appears more diffuse and somewhat dimmer. Interestingly, it too was discovered by Herschel, exactly one month after his observation of the Flame Nebula.
Barnard 33, better known as the Horsehead Nebula, is a dark nebula with a strikingly recognizable shape. It was discovered in 1888 by Williamina Fleming using photographic plates. This nebula consists of cold gas and dust that absorb visible light, appearing as a dark silhouette against the glowing background of IC 434.
NGC 2023, by contrast, is a reflection nebula located approximately 1,500 light years from Earth. It surrounds the young, massive star HD 37903, a B-type star. The star’s radiation illuminates the surrounding gas and dust, producing a bright reflection and making the nebula a relatively easy target for study. Star formation processes are still actively taking place within it.
December 24, 2024, around 9:30 PM – Jaworzno (Poland)
Suburban conditions, moderate light pollution
Orion is such a magnificent constellation that I often admire it with the naked eye, without any photographic equipment. However, after some time since my previous imaging attempts, I once again pointed my telescope toward the region of Orion’s Belt, specifically near Alnitak.
Space is an immense realm filled with fascinating phenomena and mysteries that continually spark our curiosity. A glance at the night sky reveals hundreds of thousands of stars, each a distant sphere of gas whose light has traveled for billions of years to reach our planet. Our galaxy, the Milky Way, is just one of millions of such structures that make up the Universe. Galaxies, stars, planets, and black holes are all parts of a vast cosmic tapestry that scientists strive to understand. Although space may seem far beyond our reach, modern technology and human ingenuity allow us to explore regions millions of light years away. These discoveries not only expand our understanding of the Universe but also offer insights into ourselves and our place within this infinite cosmos.
I must admit that the opportunity to observe and reflect upon such magnificent objects offers a deeply moving experience, both aesthetic and profoundly transcendental.
Photo 1 Parameters:
- Total exposure time: 10 seconds (single shot)
- Panasonic dmc-fz7
- ISO: 400
- Lens: f=6mm
- Aperture: f/1.4
- Mount: photographic tripod
Photo 2 Parameters:
- Total exposure time: 40 minutes (stack of 20 RAW frames at 120s each, using an appropriate number of dark, bias, and flat frames)
- Canon EOS 300D
- ISO: 3200
- Lens: zoom type (used at fmax = 250mm)
- A filter was used to reduce the effects of artificial light pollution and atmospheric glow
- Mount: equatorial mount with tracking, aligned using the drift method and controlled by a custom-built system.
Photo 3 Parameters:
- Total exposure time: 50 minutes (stack of 200 RAW frames at 15s each)
- DWARF3
- Lens: f=150mm (aperture: 35mm)
- Mount: photographic tripod
Marek Ples