Stellar Occultations by Nix(II) in 2011 and 2012 of UCAC Stars

The following occultation predictions are based on the nominal catalog positions of the star catalogs, they have not been refined by special astrometry. Therefore, the predictions should only be used as a first guess for planning or preparing astrometrical observations.

     Date     U.T.    Durn  Star   Mag-Drop Elon  Star             R.A. (J2000)  Dec.       
   y   m  d  h   m   sec/m   mag    V     R   o  No.             h  m   s      o  '   "  
.... ... .. .. ....  ..... ....  .... ....  ...  ........       .. .. ...... ... .. .....
2011 Jan  8  4 46.4   2.4s 14.7   8.9  9.0   13  24674361       18 22 54.186 -18 49 53.24
2011 Jan 21 21 48.4   2.6s 16.4   7.2  7.7   26  24676029       18 24 53.452 -18 49 29.52
2011 Feb 25 17 43.7   4.0s 13.1  10.5 10.8   60  24680883       18 28 58.981 -18 46 50.43
2011 Feb 26  4  2.4   4.1s 15.9   7.7  7.7   60  24680937       18 29  1.312 -18 46 48.21
2011 May 18  4  3.4   5.1s 15.2   8.3  8.8  140  24681513       18 29 22.374 -18 44  2.61
2011 Jun  3 16 40.0   4.0s 15.8   7.7  7.3  156  24679165       18 27 56.827 -18 45 26.17
2011 Jun 22 18 34.6   3.6s 15.2   8.3  8.0  173  24677167       18 25 59.918 -18 48  1.84
2011 Jul 14  6 11.9   3.7s 15.8   7.7  7.7  164  24674940       18 23 43.643 -18 51 56.50
2011 Dec  3 11 58.1   2.6s 15.9   7.7  7.3   25  24430494       18 26  4.045 -19 19 27.55
2011 Dec  4  8  7.7   2.6s 14.8   8.8  9.1   25  24430624       18 26 11.129 -19 19 30.67
2011 Dec 19 23  1.6   2.4s 15.5   8.1  7.7   10  24433501       18 28 27.553 -19 20  1.73
2012 Jan 25 16 37.6   2.6s 15.0   8.6  8.2   27  24439681       18 33 53.213 -19 18 47.85
2012 Feb 13  6 49.7   3.2s  9.9  13.7 13.4   46 T6275-00289-1u  18 36 14.631 -19 17 12.78
2012 Feb 14  3 37.4   3.2s 14.9   8.7  8.7   46  24441392       18 36 20.575 -19 17  8.25
2012 Feb 15 18 31.4   3.3s 15.5   8.1  8.0   48  24441570       18 36 31.472 -19 17  0.29
2012 Jul  8 11 46.2   3.6s 14.7   8.8  8.7  170  24439127       18 33 14.359 -19 22 12.21
2012 Jul 19  7 31.4   3.8s 14.2   9.3  9.0  160  24438158       18 32  7.969 -19 24 36.14
2012 Sep 11  6 54.8  17.7s 15.3   8.3  8.2  108  24192350       18 28 45.257 -19 37  7.57
2012 Nov 28 16 33.8   2.7s 15.3   8.4  9.0   31  24196365       18 33 59.428 -19 48 22.99
2012 Dec 16  0 23.9   2.4s 15.2   8.5  8.5   15  24198495       18 36 26.116 -19 48 40.33
2012 Dec 23  0 56.0   2.4s 13.3  10.4 10.5    8  24199500       18 37 28.484 -19 48 31.63

Calculated using  WINOCCULT Version 4.0.8.16 with DE 423 and an position offset according to the following procedure:

An offset of Pluto's position versus DE413 is calculated by Bruno Sicardy from real occultations observed in the last 10 years. It may not be correct for the future, but may be the best approximation we can do at the moment.

This offset versus DE413 is converted in an offset versus DE423, which is the basis of the latest version of WINOCCULT 4.0.4.16.
Because of the approximate position of the stars, which may cause errors larger than Pluto's diameter, the offsets have been calculated only once for each year, at 2011.5 and 2012.5

2011:Offset in Declination: +75 mas, in Rectascension: +88 mas

2012:Offset in Declination: +86 mas, in Rectascension: +115 mas

UCAC stars have been used without any restriction. Events with a reasonable area of visibility have a link to a map with local circumstances. But keep in mind, relatively large errors are possible.

These data are only a first basis for your observation plans.

The table gives the following data:

Date and UT
The UT date and time of closest approach to the specified site [that is, the time listed here does depend on the site location, for both Local and Global summaries].

Duration 
This column gives the predicted maximum duration, in seconds or minutes.
 
Star mag
Star magnitude - visual

Mag drop V
Magnitude drop at occultation - based on visual magnitude

Mag drop R
Magnitude drop at occultation - based on the star's red magnitude, and an asteroid color (B-V) of 0.83. This may be a better guide for CCD observers

Elong
The solar elongation of the star, in degrees

Star number
The 2UCAC number of the star being occulted or the Tycho number

RA Dec
The J2000 coordinates of the star

Wolfgang Beisker

International Occultation Timing Association - European Section
Research and Development