Wednesday, January 18, 2012
A Re-analysis of My Comet 103P Images (and the original FITS files)
As you may know, one of my comet images has been taken and modified to give the appearance that there is an unknown planet in it (see here and here for details and a bunch of free resources to play with).
It's been 2 years since I first processed this image, and I've learnt a few tricks since then. S0 I went back and re-analysed them.
This time I stretched the images in FITS Liberator (Arcsin stretch), saved as TIFF, stacked the TIF's in ImageJ, registered the images, then used a Z project to SUM the stack. After this I used a square root transform to bring out the fainter details.
Click to embiggen the image (comet 103P Hartley2, and PGC 7154, taken on 18-09-2010), and compare it with my original stack.
I've been able to bring out the comets tail without over exposing the head, like last time. The galaxy PGC 71451 is more disappointing, but I haven't fiddled with the contrast to really bring it out.
One thing that is definitely NOT there is a crescent planet. You can even see the enhanced star diffraction spike running right through where the planet was later pasted in.
If anyone else wants to play with the raw FITS files, you can access them here (warning each file 3.5 Mb zip archives)
Process away, but do acknowledge where you got them from.
Oh and here is the header file, which you can extract from the original FITS files with any suitable image processing program:
SIMPLE = T
BITPIX = 16 /8 unsigned int, 16 & 32 int, -32 & -64 real
NAXIS = 2 /number of axes
NAXIS1 = 2184 /fastest changing axis
NAXIS2 = 1472 /next to fastest changing axis
BSCALE = 1.0000000000000000 /physical = BZERO + BSCALE*array_value
BZERO = 32768.000000000000 /physical = BZERO + BSCALE*array_value
OBJECT = '103P_18-09-0' / Target object name
TELESCOP= 'ACP->GRAS-005 TAK E250' / Telescope name
INSTRUME= 'SBIG ST-10 3 CCD Camera' / Detector instrument name
OBSERVER= 'Ian Musgrave' / Observer name
NOTES = ' '
DATE-OBS= '2010-09-18T08:04:03' / [ISO 8601] UTC date/time of exposure start
[snip lines if guff]
HISTORY File was processed by PinPoint 5.0.14 at 2010-09-18T08:05:56
DATE = '18/09/10' / [old format] UTC date of exposure start
TIME-OBS= '08:04:03' / [old format] UTC time of exposure start
UT = '08:04:03' / [old format] UTC time of exposure start
TIMESYS = 'UTC ' / Default time system
RADECSYS= 'FK5 ' / Equatorial coordinate system
AIRMASS = 1.07641649772E+000 / Airmass (multiple of zenithal airmass)
ST = '00 52 23.96' / Local apparent sidereal time of exp. start
LAT-OBS = 3.29035555556E+001 / [deg +N WGS84] Geodetic latitude
LONG-OBS= -1.05528305556E+002 / [deg +E WGS84] Geodetic longitude
ALT-OBS = 2.25000000000E+003 / [metres] Altitude above mean sea level
OBSERVAT= 'G5 - The Stefano Padovan Wide-Field Observatory' / Observatory name
RA = '23 25 01.19' / [hms J2000] Target right ascension
OBJCTRA = '23 25 01.19' / [hms J2000] Target right ascension
DEC = '+47 29 19.8' / [dms +N J2000] Target declination
OBJCTDEC= '+47 29 19.8' / [dms +N J2000] Target declination
CLRBAND = 'R ' / [J-C std] Std. color band of image or C=Color
Start at 20:06. You won't believe
how stupid he can be at times.
Anyway thanks yet again for giving us the correct time stamp. The cultists may live another day without jumping off a cliff.
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