Images of Comet 73P/Schwassmann-Wachmann 3, fragments B and C

All images were taken with the Skinakas Observatory 30cm Schmit telescope during the night 09-10 May 2006.The telescope was tracking at sidereal rate. The raw images were taken with the Photometrics (Roper Scientific) CCD camera CH260, which was cryogenically cooled to -115 degrees Celsius. The filters used were standard Johnson B, V and Johnson-Cousins R. Weather conditions were not ideal - non-photometric night - and the sky was relatively bright ( moon was
close to full).
The images were fully reduced (bias subtracted and flat-fielded) with the ESO-MIDAS and IRAF astronomical software.
The processing was done using the MaximDL (Diffraction Limited) and Photoshop (Adobe). The intensity scale in all images
is logarithmic while the linear scale of the images is 4.125 arcseconds per pixel. In all images North is up and East to the left.
 

Left: frgB_20x20sec_R_anim4fps.gif,  Right: frgC_20x20sec_R_anim4fps.gif:
20 images of fragment B (and C) of the comet 73P taken sequentially with a time interval of 108 secs through the R filter with 20 sec exposure time were combined to produce this animation. It shows the motion of the comet relative to the background stars. The sequence spans a time interval from UTC 23:47
May 10 to UTC 00:05 May 11 2006 (and UTC 01:00 May 11 to UTC 01:18 May 11 2006).

frgB_60sec_med_RGB: True color composite image in logarithmic scale of fragment B of comet 73P. Red, Green and Blue channel components were obtained by the median combination of sets of 4 images taken sequentially through B, V and R filters with exposure time of 60 seconds. The three sets of images were first aligned on the nucleus of the B fragment of the comet. The median combination of the images had as a side-effect the removal of the background stars, even though a few leftovers are visible in the image (colored spots). The reason for these left-over stellar images is that each original image had a very dense stellar background, since the comet was projected on the sky near the plane of our Galaxy (as seen from Earth). A faint tail is visible in the image and extends for about 28 arcminutes, which corresponds to a length of about 87500 km in space while the comet nucleus was at a distance of about 10.8 million km from the earth.

frgC_60sec_med_RGB: Same as previous image but for the fragment C of the comet 73P. The fainter tail now extends for about 10 arcminutes

 frgB_all60sec_med_R: Image of fragment B of the comet resulted from the median combination of 14 CCD images taken through the R filter with 60 sec exposure time each. The faint tail is revealed better in this image and extends for about 38 arcminutes, a bit larger than the apparent angular diameter of the moon or the sun on the sky, which is 30 arcminutes.

  frgC_all60sec_med_R: Same as previous image but for fragment C. The tail angular extend is about 21 arcminutes on the sky.