December 15, 2018 14:28UT at 0.077668AU from Earth near the Pleiades in Taurus.
  The bright white star at the left top of the comet is HD 24262, at the right is HD 24278.

Comet 46P/Wirtanen

Video

A sequence of 10 frames each 35 seconds apart shows the motion of the comet relative to the stars.

 

Characteristics

For a comet with moderate eccentricity of 0.6588, the mean distance to the sun is 3.09267AU with a period of 5.439 years while its perihelion distance is 1.05535AU. Its estimated radius is 560 meters (axial ratio >1.4). The Jupiter-family comet spins around its axis once in 7.6 hours. On December 16th, 2018 at 13:05 UT, less than four days after perihelion, 46P passed Earth at a (perigee) distance of 0.07746AU, or about 11.1 million kilometers, or 30.1 lunar distances shining at 3.2 magnitudes near the Pleiades star cluster in Taurus. The comet will be observable in the northern hemisphere for several months longer, but naturally much fainter.

Wikipedia: "46P was the original target for close investigation by the Rosetta spacecraft, planned by the European Space Agency, but an inability to meet the launch window caused Rosetta to be sent to 67P/Churyumov-Gerasimenko instead." No regrets, 67P was a great success for ESA.

Current Position

Click for an enlarged closeup chart centered on the comet.

 

Current Ephemerides

refreshed every 10 sec

 

 

Imaging

The two images below are made of the same stack of ten 30-second tracked exposures at ISO6400 and processed with the 'magic' Deepsky Stacker software. The 'Star Motion' stack centers on the comet and ignores trailing stars, while the 'Comet Motion' stack ignores the position of the comet and shows the stars pinpoint. The latter demonstrates how fast the comet is traveling relative to the stars considering that the image is composed of ten 30-second exposures with a 5 second pause = 350 seconds or hardly six minutes. Obviously, the comet has assumed a strong momentum after its perihelion passage, now gradually slowing down. The green color is the fluorescing cometary atmosphere or coma spanning about the size of a full moon.

The image sequence was captured on December 15th, 2018 at 14:28 UT when the comet was 11.619 million kilometers away from Earth, 2 days and 16 hours after perihelion passage.

 

Star Motion

Comet Motion


Equipment used: Vixen A80Mf Ø80mm achromat, 910mm focal length (f11.4) and a Nikon D5300 DSLR in the prime focus, horizontal FOV is about 1.5°.