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C/2012 F6 (Lemmon)

Comet Lemmon is currently putting on a great display in the southern sky right above New Zealand! You won’t wander outside and see a bright naked-eye comet with a long tail but rather a nice fuzz ball patch with binoculars or a telescope. Lemmon has surprised the comet community by shining about four magnitudes brighter than expected – e.g. today (25/1/13) it is magnitude 7.5 when most planetarium programmes say it will be mag 11.5!

C/2012 F6 (Lemmon) was discovered on the 23rd March 2012 by A.R. Gibbs as part of the Mount Lemmon Survey (Tucson, Arizona). It was then at magnitude 20.7. As with all comets, predetermining the magnitude is a bit like picking the Lotto numbers. However, revered comet observer and comet webpage master Seiichi Yoshida from Japan produced the following model based on current magnitude estimates:

Comet Lemmon will continue to be seen in the New Zealand evening skies until about 20 March 2013 when it may be about magnitude 5. It will then slip into the Sun’s glare and re-emerge briefly and lowly in the morning sky from about the 29th April until the 29th May - after which it is too far north to be seen from NZ (declination + 33).

The following are ephemerides for C/2012 F6 (Lemmon) during the periods it should be observable from New Zealand (roughly subtract 4 from the predicted magnitude).

    Evening (NZST) – 
    Lemmon (C/2012 F6)
    Date                  RA            declination     r      delta   mag Elong  Alt    Azim
    ----                  --            -----------     -      -----   --- ----- ------ ------
    25 Jan 2013 20:26:59  12h44m29.81s  -69 24' 19.3"  1.3145  1.0366 11.3  81.1  26.10 160.64 Mus
    28 Jan 2013 20:26:59  12h57m32.72s  -74 39' 35.7"  1.2722  1.0124 11.1  79.1  29.51 165.17 Mus
    31 Jan 2013 20:26:59  13h23m26.72s  -79 59' 42.8"  1.2302  0.9957 10.9  76.8  32.41 170.46 Cha
     3 Feb 2013 20:26:59  14h43m09.31s  -85 02' 48.8"  1.1885  0.9867 10.7  74.1  34.65 176.44 Oct
     6 Feb 2013 20:26:59  20h12m42.61s  -86 36' 17.5"  1.1473  0.9852 10.6  71.2  36.08 182.90 Oct
     9 Feb 2013 20:26:59  22h48m14.39s  -82 13' 30.6"  1.1066  0.9912 10.4  68.0  36.62 189.58 Oct
    12 Feb 2013 20:26:59  23h26m01.06s  -77 03' 40.5"  1.0666  1.0039 10.3  64.8  36.26 196.14 Hyi
    15 Feb 2013 20:26:59  23h42m06.32s  -71 56' 31.8"  1.0275  1.0229 10.2  61.4  35.07 202.28 Tuc
    18 Feb 2013 20:26:59  23h51m00.55s  -67 00' 16.9"  0.9894  1.0475 10.1  58.1  33.15 207.78 Tuc
    21 Feb 2013 20:26:59  23h56m38.73s  -62 17' 44.4"  0.9527  1.0767  9.9  54.7  30.65 212.55 Tuc
    24 Feb 2013 20:26:59  00h00m29.59s  -57 49' 48.8"  0.9175  1.1097  9.9  51.4  27.70 216.56 Tuc
    27 Feb 2013 20:26:59  00h03m14.07s  -53 36' 21.3"  0.8842  1.1459  9.8  48.2  24.43 219.85 Phe
     2 Mar 2013 20:26:59  00h05m13.92s  -49 36' 33.8"  0.8531  1.1843  9.7  45.1  20.92 222.51 Phe
     5 Mar 2013 20:26:59  00h06m41.93s  -45 49' 15.2"  0.8247  1.2242  9.6  42.1  17.25 224.61 Phe
     8 Mar 2013 20:26:59  00h07m46.36s  -42 13' 02.3"  0.7992  1.2648  9.5  39.2  13.47 226.22 Phe
    11 Mar 2013 20:26:59  00h08m32.97s  -38 46' 28.5"  0.7772  1.3056  9.5  36.4   9.61 227.43 Scl
    14 Mar 2013 20:26:59  00h09m06.12s  -35 28' 08.7"  0.7591  1.3459  9.4  33.8   5.71 228.30 Scl
    17 Mar 2013 20:26:59  00h09m29.43s  -32 16' 44.2"  0.7453  1.3850  9.4  31.4   1.77 228.86 Scl
    20 Mar 2013 20:26:59  00h09m46.08s  -29 11' 05.7"  0.7361  1.4226  9.4  29.2  -2.19 229.18 Scl
    
    Morning (NZST) – 
    Lemmon (C/2012 F6)
    Date                  RA            declination     r      delta   mag Elong  Alt    Azim
    ----                  --            -----------     -      -----   --- ----- ------ ------
    25 Apr 2013  5:11:11  00h14m55.13s  +03 15' 22.1"  0.9530  1.6840 10.9  29.8   9.28  78.12 Psc
    28 Apr 2013  5:11:11  00h15m41.45s  +05 47' 01.4"  0.9898  1.6927 11.1  31.7   9.74  74.35 Psc
     1 May 2013  5:11:11  00h16m28.39s  +08 17' 16.7"  1.0278  1.7003 11.3  33.7  10.14  70.61 Psc
     4 May 2013  5:11:11  00h17m14.99s  +10 46' 16.1"  1.0669  1.7067 11.4  35.8  10.48  66.88 Psc
     7 May 2013  5:11:11  00h18m00.16s  +13 14' 06.7"  1.1069  1.7123 11.6  37.9  10.74  63.16 Psc
    10 May 2013  5:11:11  00h18m42.78s  +15 40' 55.0"  1.1476  1.7172 11.8  40.1  10.91  59.46 Psc
    13 May 2013  5:11:11  00h19m21.68s  +18 06' 46.1"  1.1889  1.7215 11.9  42.3  11.00  55.79 Psc
    16 May 2013  5:11:11  00h19m55.65s  +20 31' 44.1"  1.2306  1.7255 12.1  44.6  10.98  52.13 Psc
    19 May 2013  5:11:11  00h20m23.47s  +22 55' 51.8"  1.2726  1.7292 12.2  46.8  10.86  48.50 And
    22 May 2013  5:11:11  00h20m43.87s  +25 19' 10.4"  1.3149  1.7328 12.4  49.1  10.62  44.90 And
    25 May 2013  5:11:11  00h20m55.52s  +27 41' 40.1"  1.3573  1.7365 12.5  51.3  10.27  41.34 And
    28 May 2013  5:11:11  00h20m56.97s  +30 03' 19.5"  1.3998  1.7403 12.7  53.5   9.79  37.82 And
    31 May 2013  5:11:11  00h20m46.61s  +32 24' 05.9"  1.4424  1.7444 12.8  55.8   9.20  34.35 And
     3 Jun 2013  5:11:11  00h20m22.53s  +34 43' 54.6"  1.4851  1.7490 12.9  58.0   8.47  30.93 And
    

John Drummond Director – RASNZ Comet and Meteor Section (25/1/13)

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