Comet Machholz - Jan. 2005
Scope: Megrez II f/2.6 Location: Dos Picos Park, Ramona, CA 15 Jan. 2005 (7:45 UT) Camera: ToUcam SC3
Exposure: 16 x 40 sec, 16 x 12 sec, and 16 x 4 sec Luminance Exposures with IR Block and Orion SkyGlo filters. 12 x 24 sec RGB Exposures
Processing: Images were captured in K3CCDTools 2. Aligned/stacked in Registax 3 and saved as FITS. Luminance and Color channels were scaled and rough color balanced in IRIS. Channels were co-registered in IRIS. The 40 sec IR block exposure was used as the main luminance channel; the 12 second exposure was used to minimize star size somewhat and to help resolve the comet core a little better. The 4 sec IR block exposure was not used. The comet structure was extracted and subtracted from the 12 sec IR block, R,, G, and B exposure star fields. The extracted comet structure for each of these exposures was aligned with that of the 40 sec Luminance and then added back to their respective exposures. This bit of manipulation was needed to correct for the comet's movement in the star field during the exposures. Luminance and Color FITS were combined in Photoshop with Luminance Layering. Color balancing and final touches in Photoshop. SGBNR (PixInsight LE) was used to smooth background noise on Luminance channel and the final result. Image was resized to 800 x 600.
This is an unconventional exposure for a comet since the camera movement itself was not tracking the comet but instead it was tracking the star field. Processing description above covers corrective measures for this apparent error. The comet is 10 days before perihelion in this image. Comets can have two tails a dust tail and an ion tail - this image shows the ion tail. At the time of the image, Comet Machholz is traveling through the constellation Perseus. Horizontal FOV is 80'
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