Comet 46P/Wirtanen

On December 12, 2018 Comet 46P/Wirtanen  will pass the sun at it's closest distance of 157,878,113 Kilometers (98,100,911 Miles).  Just four days later, on December 16, 2018 it will come closest to Earth at 11,622,258 Kilometers (7,221,736 Miles).  On it's closest approach, it's expected to reach naked-eye brightness.

Ephemeris From Wikipedia, the free encyclopedia In  astronomy  and  celestial navigation , an  ephemeris  (plural:  ephemerides ; from  Latin   ephemeris , meaning 'diary', from  Greek  εφημερίς  (ephemeris) , meaning 'diary, journal'  [1] [2] [3] [4] ) gives the positions of naturally occurring  astronomical objects  as well as  artificial satellites  in the  sky  at a given  time  or times. Historically, positions were given as printed  tables  of  values , given at regular intervals of date and time. Modern ephemerides are often computed electronically from mathematical models of the motion of astronomical objects and the Earth. Even though the calculation of these tables was one of the  first applications of mechanical computers , printed ephemerides are still produced, as they are useful when computational devices are not available. The astronomical position calculated from an ephemeris is given in the  spherical polar coordinate system  of  right ascensi

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