The comet which has been discovered by the American astronomer Carl Alvar Wirtanen in 1948, came to a historic proximity to us on December 16, 2018. The distance from our planet was the tenth closest modern comet and when we look at all the comets known by mankind, it was the sixteenth closest to us. The comet 46P/Wirtanen at the time of its proximity to 2018, traveled 11.5 million kilometers next to our planet, a distance thirty times the average distance of the Earth-Moon. The list of closest comets to the Earth is led by the 1770 Lexell comet (D/1770 L1). This comet missed the Earth just 2.2 million kilometers.
Thanks to the diatomic carbon molecules, this celestial wanderer with a green coma, orbit around the Sun between the Jupiter and Earth orbits, with a period of only 5.43 years. The observability of 2018 has been the best since it was discovered. Especially favored by the proximity to the Earth is that from the second half of December 2018 the comet can be seen as a circular polar body from Hungary. However, due to its drift away from the Sun, its brightness is drastically reduced and in February 2019 it is only possible to look at more serious astronomical equipment.
Interestingly, the comet's Rosetta spacecraft mission was also designed for this comet, but due to a lack of time, another body had to be chosen. Finally, Rosetta's journey was directed at the 67P/Churyumov–Gerasimenko comet, where it conducted researches between 2014 and 2016 and landed his landing unit Philae in 2015 on the comet's surface.
The Wirtanen comet is one of the "hyperactive" comets. The Jupiter comet family's celestial wanderer is characterized by high levels of dust and gas emissions. The more optimistic predictions predicted by mid-December 3 magnitudes - visible to the naked eye - but finally the more pessimistic estimates of 4-5 magnitudes were confirmed. The thin and pale tail of the Christmas comet was shown for a short period of time at the end of November and early December, but typically in an apparent size is huge - approx. we could examine a full-moon coma (the head of the comet), slightly elongated. It can be stated that the hyperactive comet was active during the 2018 perihelium (proximity to the Sun), but there was no more extreme activity producing higher brightness.
Unfortunately, Hungary's weather was not gracious for me, so I missed two spectacular conjunctions: on the 17th of December, the Pleiades and on 23rd of December the Capella star were near. Fortunately, on December 26th, it was a clear evening. I managed to capture the comet before the moonrise, thus increasing the information content of the image. In determining the exposures, I tried to use short shutter speeds to make the comet's own movement, otherwise fast, in the pictures insignificant.
Using my comet and star aligned pictures, I made animations about Wirtanen's move. Unlike my habits, a werk image was taken during photography (at the bottom of the page).
R.A. 05 h 59 m 24 s Dec. +51° 29′ 06″
Distance from Sun:
160 million km
Distance from Earth:
14.8 million km
26/12/2018 17:41-18:19 UT
Total exposure time:
Tápióbicske, Pest, Hungary
Canon EOS 1300D (modified)
Home-made 200/800 mm Newtonian reflector
Sky-Watcher EQ6-R Pro GoTo
Sky-Watcher f/4 coma corrector
Focal ratio, length:
f/4, 800 mm
65 x 30 s
PixInsight, Adobe Lightroom, Adobe Photoshop
Until now, it was technically impractical, but now with my unmodified Nikon camera, I took advantage of the dead time next to the telescope and made a werk photo.
26/12/2018 18:04 UT
AF-S DX Zoom-Nikkor 18-55mm f/3.5-5.6G ED II
20 sec, ISO 3200, 18 mm / f/3.5
Processing: Adobe Photoshop, Adobe Lightroom