The dream of a Japanese amateur astronomer

C/2018 Y1 (Iwamoto)
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On December 19, 2018 (Japanese Time), Japanese amateur comet hunter Masayuki Iwamoto noticed a slow-moving diffuse celestial body in his photographs about Hydra's constellation. Iwamoto's equipments are a Canon EOS 6D connected to the 10 cm Pentax Apocormate f/4, which was enough to capture the 12th magnitude comet that were approaching towards Earth.

This was not the first success for the Japanese amateur since he discovered his first comet in 2013: C/2013 E2 (Iwamoto). In November 2018 he was a co-discoverer for the C/2018 V1 (Machholz-Fujikawa-Iwamoto) comet.


These comets are clearly surpassed by the discovery of C/2018 Y1 (Iwamoto), as it is currently projected to be the brightest comet in 2019. It is a great pleasure that in the shadow of automated comet search programs, it is still meaningful to observe the sky in an amateur way and make such world-famous discoveries.

The comet arrived in perigee on February 12-13, 2019 (minimum distance: 45.45 million km), and its perihelion was on February 7th (minimum distance from Sun: 193 million km). The celestial wanderer is orbiting with a 1371-year period, that is, in 3390 it appears again in the inner Solar System. The furthest point of its orbit from Sun is far from the 245 AU. 

The comet's appearance is like seeing the Wirtanen's little brother, but still a little different. Similar is the structure and appearance of coma. The apparent size of this comet like the Wirtanen's. The green color here is also due to the double-core carbon molecules.

Its activity increased over the previous nights before shooting, and its brightness was slightly brighter than expected. The comet's tails appeared differently every day. On the 12th of February before the capturing, two larger tails were typically observed about 90 degree PA spacing. On February 13th, only one of these tails remained, but in addition I managed to capture a thinner one. Iwamoto's tail is like a swallow's tail. The tails could not be visually detected in the reflector, it was difficult to capture them.

The comet travels alongside galaxies and other spectacular photographic objects in February 2019, unfortunately my options were limited, so I can see only a few PGC galaxies on my picture. The next day I tried to capture the comet and the NGC 2903 galaxy, but the clouds prevented my plan.

In determining the exposures, I tried to use short shutter speeds to make the comet's own movement - otherwise it was very fast - in the pictures insignificant. Using my star-aligned images, I also created an animation.

Featured dates:
11 Feb 2019: Passes near to the M 95 and M 96
12 Feb 2019: 3 degrees from Regulus, passes next to the η Leo
13 Feb 2019: Passes through the edge of NGC 2903 galaxy
18 Feb 2019: Passes next to the Castor
28 Feb 2019: Passes through the open clusters M 36 and M 38
2 Mar 2019: Passes through the edge of IC 405

Name:

C/2018 Y1 (Iwamoto)

Constellation:

Leo

Coordinates:

R.A. 09 h 54 m 38 s Dec. +18° 25′ 03″

Type:

Comet

Distance from Sun: 

193 million km

Distance from Earth:

45 million km

Apparent size:

Coma: 25'; tails: 30' (PA 130°); 20' (PA 150°)

Brightness:

6.3m

Sidereal period:

1371.6 years

Velocity:

37 km/s

Date:

13/02/2019 00:41-01:06 UT

Total exposure time:

20 minutes

Location:

Tápióbicske, Pest, Hungary

Camera:

Canon EOS 1300D (modified)

Telescope:

Home-made 200/800 mm Newtonian reflector

Mount:

Sky-Watcher EQ6-R Pro GoTo

Guiding:

-

Corrector:

Sky-Watcher f/4 coma corrector

Focal ratio, length:

f/4, 800 mm

ISO:

3200

Light:

60 x 20 s

Dark:

20

Flat:

20

Bias:

20

Processing:

PixInsight, Nebulosity, Adobe Lightroom, Adobe Photoshop

Location

Annotation

Animation

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Location in the Solar System


C/2018 Y1 (IWAMOTO)

Main objects: C/2018 Y1 (iwamoto), HIP 48670

 

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