173P/Mueller
The comet or a star? Seiichi Yoshida remarked on the Comet ML, that the supposed comet is probably a star.
There are no observations of this very weak comet since July 2008.
After checking the star field with the
STScI Digitized Sky Survey,
I assume, that my observation is false. That's a pity.
� 2009-03-18 by Bernhard Haeusler, Maidbronn, Germany. Stacked image centered on the stars: movement of the comet: 5"/15min. in PA293�.
3 x 5 min. exposure,
2009-03-18, UT 01:19 to 01:34, 12" SCT
f-7 +
CCD ST10XME, IR/UV-blocking filter
19.53 mag in a squared field of aperture with 10 x 10 pixels
Star field
from POSS2/UKSTU Red
plate (created by the
STScI Digitized Sky Survey)
The full size of the POSS star field is shown in my image above in the red
squared field.
Star A and Star B are described below
The queried region: (my first measured position of 173P/Mueller for the MPC)
| Longitude/Right Ascension: | 11:33:45.2 | |
| Latitude/Declination: | 24:04:04.3 | |
| Field Width: (Square Bounds) |
5.0 (arcminutes) |
|
| Coordinate System: | J2000.0 |
Star A close to the center of the image was determined from the NED Search as:
SDSS J113344.94+240403.5 11h33m44.9s +24d04m04s * ... ... 21.8g (= Star A)
This means,. the stars has a magnitude of 21.8 with g-filter. Here you find the Query result of the NED.
The reference star is Star B extracted from the NED:
SDSS J113342.66+240458.5 11h33m42.7s +24d04m59s * ... ... 21.1g (= Star B)
Star A and the reference Star B are measured with Astrometrica (MPC result):
Star A C2009 03 18.06385 11 33 44.89 +24 04 04.2 19.3
C B82
Star B C2009 03 18.06385 11 33 42.64 +24 04 58.6 19.4 C
B82
Star B is definitely visible on my image. It has a magnitude of 19.4 measured with Astrometrica.
Stas A is obviously a little bit fainter on my image, but it is comparable with the magnitude of Star B.
This means: The comet 173P/Mueller is unverifiable on my image.
MPC observation: computed with Astrometrica
COD B82
OBS Bernhard Haeusler
TEL 0.30-m Schmidt-Cassegrain + CCD
NET CMC-14
0173P C2009 03 18.05670 11 33
45.17 +24 04 04.3 19.5 N B82
0173P C2009 03 18.06385 11 33 44.89 +24 04 04.2 19.5 N B82
Gauss curve produced by Astrometrica. The total PSF is using the
aperture circle of 3 x 3 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
------------ ---------- -------- ----- ----- ----- ----- ----- -----
---- ---- ---
173P
18/03/2009 01:26:47 19.53 18.51 17.96 17.53 17.14 16.83 3.3 19.6
B82
173P
18/03/2009 01:26:47* 0.05 0.13 0.09 0.09 0.07 0.11 3 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.
Orbit of 173P/Mueller at March, 18 2009, Sun distance: 4.41 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