174P/(60558) Echeclus

Comet 174P/(60558) Echeclus

2011 Jun 07

The remnant of the outburst around early June in 2011 is clearly seen with a diameter about 0.8-arcmin according to my measurement. The central condensation offsets about 7-arcsec in P.A. 220° with respect to the center of the remnant.

Mouseover to browse the entire version without the two specially processed images.

MPC observation computed with Astrometrica using UCAC-3 star catalog for astrometry and CMC-14 star catalog in R band for photometry:

COD C42
OBS X.Gao, M.-T. Hui
MEA M.-T. Hui
TEL 0.36-m f/6.9 Schmidt-Cassegrain + CCD
NET UCAC-3
60558 KC2011 06 07.74363 16 13 28.71 -16 25 08.8 17.9 R C42
60558 KC2011 06 07.75515 16 13 28.49 -16 25 07.7 17.9 R C42
----- end -----

Gauss curve produced by Astrometrica with CMC-14. The total PSF is using an aperture circle of 5 x 5 pixel around the brightest pixel. We can see the Gauss curve in the right is as the computed ideal line and the real pixels contributed around the ideal line. The Fit RMS, which inlays under the Gauss curve, is the deviation from the ideal line.

Photometry result computed with FOCAS II, which processes images based upon the .LOG file of Astrometrica, by means of Multibox method:

COD C42
CATALOG: USNO A2.0 / CMC-14 - BAND: R
                                   10x10 20x20 30x30 40x40 50x50 60x60 SNR SB COD
OBJECT        DATE       TIME        +/-    +/-    +/-    +/-    +/-    +/-     N FWHM CAT
------------ ---------- -------- ----- ----- ----- ----- ----- ----- ---- ---- ---
60558         07/06/2011 17:59:07 17.48 16.53 15.85 15.37 15.03 14.75 7.8 19.6 C42
60558         07/06/2011 17:59:07* 0.06 0.02 0.00 0.04 0.04 0.04     2 3.6 CMC

FoCAs II - 17/03/2010
www.astrosurf.com/cometas-obs
es.groups.yahoo.com/group/Cometas_Obs

Interpretation of the FOCAS II table headings:

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

Feel free to e-mail me with any doubts or questions.