Using a 72 mm (2.8”) diameter refractor telescope and a monochrome astronomical camera, I captured an image of one of the most iconic celestial objects visible from Earth – the Spaghetti Nebula. Its true beauty can only be fully revealed using various cameras, such as DSLR, mirrorless, or dedicated astronomical cameras, which can capture the delicate and filamentous structure resembling strands of spaghetti and vine tendrils in certain areas. The nebula represents the remnants of a supernova, the explosive death of a massive star that occurred approximately 40,000 years ago. It appears that the nebula also contains a pulsar, which is the rotating collapsed core of the original star.

The image was captured using a 72 mm (2.8”) lens diameter refractor telescope Askar FRA400 at a focal ratio f/3.9, and a monochrome astronomical camera QHY268M. Thanks to the favorable weather conditions, I was able to capture the subframes required to create the final image in just 4 hours and 54 minutes. The Spaghetti Nebula has captivated me with its beauty and uniqueness. Photographing this nebula and processing the final image were especially interesting and enjoyable, although I do wish I had been able to capture more subframes to reveal even more details of this fascinating celestial object. I processed the image using a technique called HOO_RGB* (please see below for a very short description of this techniques).

The nebula was formed by the explosion of a massive star, and the image shows the remnants of the original star. The red regions consist mainly of hydrogen, while the blue regions contain oxygen, along with other elements. Although spanning a large area of space, the nebula was only first observed seventy years ago, as it emits very weak light. The celestial object is situated on the border between the constellation of Auriga and zodiacal constellations of Taurus. This nebula is located in our home galaxy, the Milky Way, at a distance of about 3000 light-years (approximately 28,000,000,000,000,000 km) with a diameter of 150 light-years.

Recent research has discovered a pulsar, a rapidly rotating neutron star, at the center of the Spaghetti Nebula, believed to have formed during the explosion of the original star and is directly linked to the nebula [1]. The core of the dying star collapsed into a neutron star because of its intense gravitational force, while the outer layers were blown away by a powerful explosion, which is now observable as the Spaghetti Nebula. A neutron star is an extremely unusual cosmic object; even though it has a diameter of only about 10 km, it has a mass greater than that of our Sun, compressed into such a small space. Consequently, the density of a neutron star is incredibly high, and a teaspoon of neutron star material would weigh about 100 billion kilograms!

*For those unfamiliar with this technique, the HOO_RGB process involves assigning the light signal captured through the hydrogen (H) filter to the (R) color channel, and the light signal captured through the oxygen (O) filter to both the green (G) and blue (B) channels. While the HOO technique generally produces a relatively accurate color representation of the Spaghetti Nebula, the stars in HOO image can appear visually deficient in their G and B color components. To address this issue, it is recommended to remove the HOO representation of stars from the HOO image and instead incorporate stars captured separately using the standard RGB technique. Therefore, at the end of the image postprocessing, a natural RGB image of just stars was added to the HOO starless image of the nebula.

I apologize for the somewhat lengthy post, but I hope it will be useful to someone. 😊

[1] The Astrophysical Journal, 468(1), doi 10.1086/310218; The Astrophysical Journal, 654(1), doi 10.1086/510576).

Equipment and acquisition details:

The Spaghetti Nebula in HOO_RGB (the object is also known as SNR G180.0-01.7, Sharpless 2-240, or Simeis 147) • Telescope Askar FRA400 APO @ 280 mm, f/3.9, reducer Askar 0.7x, • Monochrome camera QHY268M cooled at -10 °C, mode 1, gain 56, offset 30 • Mount Sky Watcher AZ-EQ6 PRO • Guiding equipment: refractor 60 mm (f/4) with ASI ZWO 120MM-S • Narrowband filters Astronomik for Ha and OIII (6 nm); filters Astronomik for RGB; diameter of filters 36 mm; filter wheel QHYCFW3M-US • Total exposure time 4 h 54 min: (HOO nebula: Ha 27 × 300 s, OIII 26 x 300 s); (RGB stars: R 18 x 30 s, G: 20 x 30, B: 20 x 30 s) • Calibration frames: 35 flats, 40 dark flats, 50 bias • Image scale 2.7 arcsec/pixel • Image field size 4° 35' x 3° 5' • Used programs: PixInsight, Stellarium, PHD2, Astro Photography Tool (APT), Astronomy tools, SharpCap • Sky quality Bortle 4, 21.48 mag/arc sec2 • March 2023, Vurmat / Radlje ob Dravi / Slovenija