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| A blob of faint light upper right to the optocenter seems to be an artifact or a strong noise. During the observation, the comet is already placed quite low. High humidity and some high clouds. |
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| Animation displays the motion of the comet. Not all the images were used. Time stamps for individual bin 2x2 frames in the animation: 2013-02-13T, 13:16:20 UTC, 13:27:07, 13:37:17, 13:47:27, 13:57:37, 14:07:47, all in UTC. |
MPC observation computed with Astrometrica using both UCAC-4 and CMC-14 star catalogs -- the former for astrometric reduction and the latter for photometric work:
COD XXX
COM Long. 113 24 50.4 E, Lat. 23 12 47.5 N, Alt. 49m
OBS M.-T. Hui
MEA M.-T. Hui
TEL 0.08-m f/5.6 refractor + CCD
NET UCAC-4
CK12L020 KC2013 02 13.55301 02 06 40.00 +43 38 59.6 13.1 N XXX
CK12L020 KC2013 02 13.56050 02 06 41.09 +43 38 44.6 13.2 N XXX
CK12L020 KC2013 02 13.56756 02 06 42.15 +43 38 30.7 13.4 N XXX
CK12L020 KC2013 02 13.57462 02 06 43.29 +43 38 16.8 13.4 N XXX
CK12L020 KC2013 02 13.58168 02 06 44.42 +43 38 03.6 13.2 N XXX
CK12L020 KC2013 02 13.58874 02 06 45.44 +43 37 48.9 13.1 N XXX
CK12L020 KC2013 02 13.59580 02 06 46.60 +43 37 35.9 12.6 N XXX
Photometry result computed with FoCAs, which processes images based upon the .LOG file of Astrometrica, by means of Multibox method:
Fisrt line:
OBJECT, DATE, TIME: refering to their original meanings respectively
10x10, 20x20 ... 60x60: the aperture sizes of photometry in term of rectangle in arcsec that are used to measure an object's magnitude
SNR: the Signal-to-Noise Ratio for aperture photometry
SB: stars of faintest magnitude on the images used in data reduction with the used star catalog in Astrometrica, rather than the stars of faintest magnitude in the images
COD: MPC Code of the observatory
Second line:
+/-: precisions of measurement
N: the number of used images for measurement
FWHM: Full-Width-Half-Maximum of total PSF, relevant to degree of seeing
CAT: the used star catalog in Astrometrica
Because of the extreme low SNR of the comet, the photometry produced unpleasantly large residuals. I will keep monitoring the object, weather permitting.
Copyright @ Man-To Hui 2013/02/14
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| For color version please pay a visit to this page. During the observation, the comet is already placed quite low. High humidity and some fog. |
Only photometric work has been performed with this session of observation. The catalog used is CMC-14.
Radius of aperture 0 = 3.0
Radius of aperture 1 = 6.0
Radius of aperture 2 = 9.0
Radius of aperture 3 = 12.0
Radius of aperture 4 = 15.0
Radius of aperture 5 = 18.0
Radius of aperture 6 = 21.0
Radius of aperture 7 = 24.0
Radius of aperture 8 = 27.0
Inner radius for sky annulus = 30.0
Outer radius for sky annulus = 45.0
Sky SkySig SkySkw Magnitudes
8569.30 14.72 0.01 13.517+-0.045 12.503+-0.034 12.012+-0.032 11.817+-0.035 11.681+-0.040 11.571+-0.044
11.458+-0.048 11.409+-0.055 11.412+-0.064
I applied my IDL routine for calculating the infinite aperture magnitude of this comet. I obtained $ m_\infty = 11.423 \pm 0.037$, a good match to results from visual observations during this time.
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Copyright @ Man-To Hui 2013/03/18
Feel free to e-mail me with any doubts or questions.
