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In an earlier post a while ago, I discussed about possibility to have a very bright comet this November/December. The updates are mostly disappointing as comet ISON does not perform the best expected. Alan Mac Robert from Sky and Telescope reviews the status of this comet recently and provided realistic estimated for expected brightening:

It can still be cached by small telescopes. However, the chance of having a bright (naked-eye) comet like Hale-Bopp is not significant.

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Discovered a few weeks ago, comet C/2012 S1  is predicted to be the brightest comet in the last few centuries ! Some people already called it a dream comet. I think many people still remember spectacular shows of Comet Hyakutake and  Hale-Bop. I have observed both when I was a bachelor student. But this new comet is predicted to be shortly as bright as full Moon. In the nearest distance to the Earth, it will be about 0.4 AU away from us, comparable to the great comet of 1680.

The great comet of 1680

However, I am concerned if we can ever watch this comet that spectacular. The nearest passage on 28 November 2013, it has a distance of about 1.8 million kilometers from the solar center (twice of the great comet of 1680). Considering the solar radius of about 695,000 km, that means it will be at a distance of about two solar radii from the solar surface. It is well “in” the solar corona.. Well, sungrazing comets survive even closer distance from the sun in perihelion. Lets see  if it can survive this dramatic passage.

NASA JPL predicted the following ephemeris for this comet. The table lists the date, right ascension and declination, as well as the apparent visual magnitude of the comet:

*************************************************************
Date                             R.A.             DEC                      MAG
*************************************************************
2012-Oct-01      08 16 15.64    +27 48 11.7           17.98
2012-Nov-01     08 21 30.69   +28 07 20.5           17.44
2012-Dec-01     08 14 29.76    +29 10 23.0           16.87
2013-Jan-01     07 51 24.41    +30 43 46.2           16.30
2013-Feb-01     07 17 30.61    +31 43 49.6           15.84
2013-Mar-01    06 50 55.54    +31 32 54.6          15.54
2013-Apr-01     06 37 34.44    +30 34 47.7          15.23
2013-May-01    06 41 38.71    +29 27 23.0         14.88
2013-Jun-01     06 59 16.67    +28 14 15.3          14.37
2013-Jul-01      07 25 33.62    +26 50 47.2         13.67
2013-Aug-01     07 59 58.82    +24 55 45.5         12.68
2013-Sep-01     08 41 49.95    +22 07 43.3         11.28
2013-Oct-01     09 34 32.27    +17 37 46.8          9.26
2013-Nov-01     11 12 17.58    +06 22 36.3         5.64
2013-Nov-01     11 12 17.58    +06 22 36.3         5.64
2013-Nov-11     12 16 17.67    -02 06 57.1          3.71
2013-Nov-21     14 02 19.97    -14 55 26.6         0.73
2013-Dec-01     16 19 20.89    -14 02 53.8          n.a.
2013-Dec-11     16 10 33.49    +05 18 36.2         1.42
2013-Dec-21     16 13 52.09    +31 55 14.6         2.76
2013-Dec-31     16 35 13.15    +67 12 33.9         3.89
2014-Jan-01     16 40 39.24    +70 35 30.0          4.02
2014-Feb-01     04 13 57.65    +57 18 56.9          8.07

Please note that the early prediction of comet brightness is usually uncertain due to various effects, e.g. the planetary tidal force causing new orbital parameters, fragmentation, etc. At the moment, the comet is so far away that there is no clear idea about the diameter of the comet nucleus. Hence, the super bright comet C/2012 S1 should be quoted with care. Indeed, JPL quoted that the orbit is probably very poorly determined. I hope it will be at least visible to the naked eye.

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