Comet Schwassmann-Wachmann 3. May 24, 1990.
16 minutes exposure, Fuji 400 film.
5" f/5 refractor at prime focus.
Comet Schwassmann-Wachmann 3 has been a very interesting short-period comet in recent years. A member of the Jupiter family of comets, the orbital period is approximately 5.5 years. Like most short-period comets, Comet Schwassmann-Wachmann 3 was a rather faint object, generally peaking at around 9th or sometimes 8th magnitude, and displaying a short tail. The photograph below is one of the earliest that I have, and shows the typical appearance of the comet prior to the 1995 return.
During the 1995 return, the comet's nucleus was observed to split into 4 fragments. Accompanying this fragmentation, was a surge in brightness that resulted in what was expected to be a moderately faint 9th magnitude comet, being easily visible to the naked eye, peaking at around magnitude 5.7 and displaying a tail up to 2 degrees long!
Comet Schwassmann-Wachmann 3. October 19, 1995.
20 minutes exposure, Fuji 400 film.
300mm f/2.8 Pentax.
Comet Schwassmann-Wachmann 3. October 19, 1995.
10 minutes exposure, Fuji 400 film.
300mm f/6 newtonian at prime focus.
At this stage the comet was magnitude 6.4 and visible to the naked eye. A faint, narrow gas tail is visible in the images running down the centre of the broader dust tail.
Comet Schwassmann-Wachmann 3. October 19, 1995.
15 minutes exposure, Fuji 400 film.
300mm f/6 newtonian at prime focus.
Comet Schwassmann-Wachmann 3. October 19, 1995.
20 minutes exposure, Fuji 400 film.
300mm f/6 newtonian at prime focus.
Comet Schwassmann-Wachmann 3. October 29, 1995.
40 minutes exposure, Fuji 400 film.
5" f/5 refractor at prime focus.
The comet peaked in brightness during early October, and then began a slow fading as it receded from both the Sun and the Earth. However, before it faded too much, the Earth passed through the plane of the comet's orbit. This, combined with the Earth-comet-Sun geometry, resulted in one final intriguing display.
On November 22, the comet displayed a very pronounced anti-tail and presented one of the most unusual comet sights I have seen in over 40 years of comet observing. Both the normal tail and the anti-tail were similar brightness, with the coma in the middle of the 2. It made the comet look very strange!
The 2000 return of the comet was poorly placed and I was not able to make any observations. however, the 2006 return was very favourable, and some predictions had the larger fragments reaching around 7th magnitude. Also, early observations showed that what were originally 4 fragments, now numbered over a dozen. Each fragment was identified by a letter. Fragments "B" and "C" became the brightest, reaching around 7th magnitude. Several other fragments were also bright enough to be observed visually.
The first night I was able to image the comet(s) was March 5. On this night I only imaged fragment "C".
On April 2, I imaged both fragments "B" and "C".
On April 30, I tried imaging a number of fragments. "B", "P", and "R" were easily recorded, however fragment "G" was very faint. I managed to miss imaging fragment "C", which was the brightest of the fragments by making a dumb mistake. I order to save time, I planned to image fragment "B" and the fainter fragments with the 16" telescope. Fragment "C" I would image with the 10". Unfortunately, instead of fragment "C", I imaged fragment "B"!!! Sometimes it is suprising the idiot things you do during a long night!!!
By early May, photographs made with large telescopes and the HST, showed continued disintergration of the comet nuclei, particularly fragment "B". This fragmentation was also visible in images taken with smaller instruments as a change in the structure of the comae.
The same image as before, but processed with a median filter to remove the stars. Notice how the head of the comet has changed due to the nucleus undergoing further disintergration. High resolution images with the HST showed numerous fragments braking away from the main nucleus.
The same image as before, but processed with a median filter to remove the stars.
Notice how far back from the leading portion of the coma the central condensation is.
During June, I travelled to Australia for more observations of the comet, since by then it was difficult to observe from the northern hemisphere. Unfortunately the observatory I had intended to observe from was unavailable at the time. However a friend loaned me an 8" Celestron and so I was able to obtain some CCD observations as well as film images.
Fragments "B" and "C" are visible in this photograph. Fragment "C" is the brighter component.
The comet had peaked in brightness during the beginning of June and by nthe end of the month was starting to fade quite rapidly. My final attempt to photograph the comet was on August 14. Only fragment "C" could be recored.
After a very interesting return, which involved so much disintergration on the nuclei, one can only ponder what the 2011 return will have in store. indeed, will anything be visible in 2011???