The unusual green guest of the constellation Orion

C/2020 M3 (ATLAS)
gallery/c2020m3atlas_orion_terkep
gallery/c2020m3atlas_orion_cropped3_an

On June 27, 2020, an unknown object with a brightness of only 18.8 magnitude was discovered by the Asteroid Terrestrial-Impact Last Alert System program. The comet, later named C/2020 M3 (ATLAS), was then about 260 million kilometers away from our central star.

On October 25, 2020, at the time of its perihelion, or proximity to the Sun, it was 1.3 AU from the Sun, but thanks to its orbit, it only arrived proximity to the Earth after that. Its brightness increased steadily as a result, but it didn’t look really spectacular. In the first half of November 2020, a green round coma of about 10' diameter was observed. The comet arrived in an increasingly exciting area of the sky.

Orion is one of the best known and most spectacular constellations in the southern sky. It lies on the celestial equator, so it is clearly visible from all over the world, and from Hungary it is best observed in winter. The constellation also includes one of the most popular winter deep-sky object: the Orion Nebula (M42-M43), which appears as a blurry spot with the naked eye, but it is worth highlighting the Horse Nebula (Barnard 33), the Flame Nebula (NGC 2024), or the Messier 78 reflection nebula, which is well known from telescopes. These are all objects belonging to the Orion Molecular Cloud Complex, as well as colorful areas dotted with varied emission, reflection, and dark dust clouds, the largest of which is the red-glowing Barnard's Loop (Sh2 -276). The edge of Barnard's Loop is shown in the upper left corner of the image.

As a teacher, I often choose robotic images from my apartment in the capital during the school year, but during the pandemic, I was left with only that opportunity. I tried to create something unique and the transit of the C/2020 M3 (ATLAS) comet in the most beautiful area of Orion was such an unique event. On November 11, 2020, the top of the photo was taken, but it seemed like a good idea to create my first deep-sky mosaic and also photograph the Orion Nebula below. A few days later, on November 14-15, I turned the Chilescope VST optics back to Orion again and the image was complete.

Due to the short focal length, I chose relatively longer exposure times when determining the exposures. The comet’s bright green coma is striking, but my animation also shows the faint dust and ion tails.

Name:

C/2020 M3 (ATLAS)

Constellation:

Orion

Coordinates:

R.A. 05 h 24 m 59 s Dec. +00° 16′ 20″

Type:

Comet

Distance from Sun: 

193 million km

Distance from Earth:

54 million km

Apparent size:

Coma: 10';
Dust tail: 20' (PA 255°); Gas tail: 40' (PA 290°)

Brightness:

8.2m

Sidereal period:

138.9 years

Velocity:

37 km/s

Elongation:

141o

Date:

11/11/2020 (04:05-04:46 UT); 14/11/2020; 15/11/2020

Total exposure time:

80 minutes

Location:

Chilescope - El Sauce Observatory, Río Hurtado, Chile

Camera:

FLI MicroLine 16200

Lens:

Chilescope VST - Nikon 200 mm f/2

Mount:

10Micron GM1000HPs

Guiding:

Autoguiding

Focal ratio, length:

f/2, 200 mm

Light:

2 x (1 x 300 s R, 1 x 300 s G, 1 x 300 s B, 5 x 300 s Lum)

Dark:

30

Dark flat:

30

Flat:

120

Bias:

30

Processing:

Astro Pixel Processor, PixInsight, Adobe Lightroom, Adobe Photoshop

Location

Annotation

Animation

gallery/c2020m3atlas_orion_ss

Location in the Solar System

C/2020 M3 (ATLAS) In the Orion (Robotic telescope)

Main objects: C/2020 M3 (ATLAS), Messier 42, Messier 43, Messier 78