M1 - Crab Nebula
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The Crab Nebula is also simply known as the Crab. The object was first observed by John Bevis in the early 1730s, who included it in his work Uranographia Britannica, which was a star atlas. As often happens in science, the nebula was independently discovered by Charles Messier in August 1758 during his attempts to observe Halley’s Comet. This event prompted Messier to create a catalog of objects similar to the one he had observed to prevent future confusion with comets. This marked the beginning of the famous Messier Catalog. Naturally, the Crab Nebula received the honor of being the first entry, which is why it is also known as Messier 1 or simply M1.
The nebula is associated with a supernova observed primarily by Chinese astronomers in 1054. Its distance from Earth is approximately 6,300 light-years, with a diameter of about 11 light-years. At the center of the nebula lies a pulsar that emits flashes ranging from gamma rays to radio waves. It rotates rapidly, completing about 30 rotations per second.
Observations
September 22, 2020, around 11:00 pm – Jaworzno (Poland)
urban conditions, high level of light pollution
I would like to present a photograph that — despite being far from perfect — brought me a great deal of joy.
That night, I pointed the camera lens almost directly east (with a slight northern offset) so that its field of view encompassed an area approximately 20 degrees above the horizon. It was a pleasant surprise to notice an elongated and slightly blurred patch of light near the star Tianguan, which represents Zeta Tauri (ζ Tau), in a 10-minute exposure — relatively short for deep-sky objects.
At higher magnifications, the characteristic filamentary structure of the Crab Nebula becomes visible. At the first opportunity, I will attempt to capture additional, and perhaps even better, photographs of this object.
September 29, 2020, around around 11:00 pm – Jaworzno (Poland), garden
urban conditions, high level of light pollution
After four years, I returned to the Crab Nebula and took a new shot. This time, with more advanced optics and improved imaging conditions, the result was significantly better (Photo 2).
The Crab Nebula's distinctly filamentary structure, visible in the optical spectrum, encircles a bright central region. These filaments are the remnants of the outer layers of a star that exploded in a supernova, giving rise to the nebula. They consist mainly of ionized hydrogen and helium, with trace amounts of carbon, oxygen, nitrogen, iron, and sulfur. Temperatures within the filaments range from 11,000 to 18,000 K, with oxygen-rich areas noticeably hotter than their surroundings.
Photo 1 Parameters:
- Total exposure time: 12 minutes (stack of 24 RAW frames at 30s each, using an appropriate number of dark, bias, and flat frames)
- ISO: 2500,
- Lens: zoom type (used at fmax = 250mm),
- Aperture: f/4 (the smallest possible for the lens used),
- Mount: equatorial mount with tracking, aligned using the drift method and controlled by a custom-built system.
Photo 2 Parameters:
- total exposure time: 50 minutes (stack of 50 RAW frames at 60s each, using an appropriate number of dark, bias, and flat frames)
- ISO: 1600
- Maksutov-Cassegrain telescope (100/1400), prime focus exposure
- 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.
Marek Ples