74p_20090324

74P/Smirnova-Chernykh

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� 2009-03-24 by Bernhard Haeusler, Maidbronn, Germany Full Pixel version

4 x 10 min. exposure, 2009-03-24, UT 21:39 to 22:19, 12" SCT f-7 + CCD ST10XME
16.48 mag, coma: 0'20", tail: 1'15" in PA 281�

MPC observation: computed with Astrometrica

COD B82
OBS Bernhard Haeusler
TEL 0.30-m Schmidt-Cassegrain + CCD

NET CMC-14

0074P C2009 03 24.90575 09 04 28.71 +24 39 02.2 16.5 N B82
0074P C2009 03 24.91984 09 04 28.59 +24 39 01.4 16.5 N B82
0074P C2009 03 24.92688 09 04 28.53 +24 39 01.1 16.5 N B82

Gauss curve produced by Astrometrica. The total PSF is using the aperture circle of 10 x 10 pixel around the brightest pixel.
You see the Gauss curve right as the computed ideal line and the real pixels contributed around the ideal line.
The Fit RMS is the deviation from the ideal line (inlay under the Gauss curve).

Photometry computed with FOCAS II, using the Multibox method:

COD B82
OBS Bernhard Haeusler
CATALOG: USNO A2.0 / CMC-14 - BAND: R

10x10 20x20 30x30 40x40 50x50 60x60 SNR SB COD
OBJECT DATE TIME +/- +/- +/- +/- +/- +/- N FWHM CAT
------------ ---------- -------- ----- ----- ----- ----- ----- ----- ---- ---- ---

74P 24/03/2009 21:59:29 16.48 16.01 15.85 15.73 15.66 15.62 29.3 19.7 B82
74P 24/03/2009 21:59:29* 0.01 0.01 0.02 0.02 0.04 0.04 4 4.3 CMC

FoCAs II - 07/01/2009-b

FOCAS II is a tool for photometry on the base of data coming from Astrometrica. Focas is basically using the .LOG file of Astrometrica.

Explanation of the FOCAS II table headings:

Object, date and time are self-explaining.
10x10, 20x20 ... 60x60 are the measured magnitudes according to the aperture sizes of photometry in arc sec (rectancle).
SNR is the Signal-to-noise ratio for aperture photometry (calculator).
SB is the magnitude of the faintest star on the image matching with the used star catalogue. This is not the faintest star of the image!
COD is the MPC Code of the observatory.

second line:
+/- are the precisions of the measurements.
N is the number of the used images for the measurements.
FWHM is the Full-Width Half-Maximum of the total PSF: Measure of the seeing.
CAT is the used star catalog in Astrometrica.

Focas II is using the .log file of Astrometrica and is computing the photometry under different apertures (10x10 ... 60x60).
The graphs are showing the astrometric precision of the images.

74P/Smirnova-Chernykh � by Bernhard Haeusler, Germany

In February 2009 the distance to the Sun is 3.60 AU

links:

http://astrosurf.com/cometas-obs/index_i.htm Visual and CCD Observations and images from the "Cometas Obs" mailing list, using the Focas II format

es.groups.yahoo.com/group/Cometas_Obs The Spanish comet observation group in Yahoo

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