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Sketch of Comet Impact Scar Jupiter's Atmosphere

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#1 ericj


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Posted 28 December 2012 - 11:48 AM


Back on August 7th, 2009 I observed and made a sketch of a comet impact scar in Jupiter's atmosphere as well as mutual eclipse events between Io and Europa. I had planned to add it to my web page at the time but did not get the chance.

Recently when going through some of my old log books I came across it so I added it. Here is my report and sketch.

On the night of August 7th, 2009 I set up my TMB 130mm f/9.25 refractor on an alt-mount to observe several Jupiter events over three and a half hours, from around 3:30 UT to around 7:00 UT. This included first, to observe a transit of the Great Red Spot (GRS) which took place at 4:31 UT.

Second, to observe the mutual eclipse events between Io and Europa which occurred between 5:10 UT - 5:40 UT. This included Io casting a shadow on Europa stating around 5:10 UT, and Io eclipsing a portion of Europa around 5:40 UT.

Third, to observe the Wesley Comet Impact scar in the South Polar Region of Jupiter around 6:30 UT. In July 2009 Australian amateur astronomer Anthony Wesley had photographed an impact scar in the South Polar Region of Jupiter that was most likely caused by a comet

The weather as I was observing Jupiter was not the best as although it was clear it was also breezy. Each time the breeze picked up the seeing got worse, even though this helped to cut down on the number of mosquitoes looking for a late night snack. Hence the seeing from around 3:30 UT - 5:30 UT varied from poor to fair to once in a while settling down to good for brief moments, so I could only use a magnification of between 179x - 209x.

I made my first sketch as the GRS transited the Central Meridian. Some of the detail that was visible included the South Polar Region appeared green gray, while the South Equatorial belt appeared light brown in color. The Great Red Spot appeared small within the Red Spot Hollow.

The North Equatorial Belt (NEB) appeared red brown. It had an irregular outline to it and some light blue festoons were visible along the NEB south (NEBs). The North Polar Region appeared green gray in color.

After a short break I swung the telescope over to observe Io and Europa. By around 5:08 UT Europa appeared slightly dimmer than it had before. By 5:15 UT Europa appeared dimmer still. By 5:20 UT Europa appeared dimmer and smaller in size.

By 5:30 UT Io and Europa were very close to each other, and reminded me of a double star, Io yellow in color while Europa was white in color. With steady seeing conditions I can often distinguish the moons by their color and size, but not so on this night with the seeing until they were very close to each other. By 5:35 UT Io and Europa appeared to be in contact with each other and it reminded me of an
elongated star.

By 5:45 I could start to see separation between Io and Europa, and by 5:50 UT they reminded me of Alberio.

I took another short break before observing the Wesley Impact scar as shown in the sketch above. The seeing had improved at this point to fair to good so I was able to use a higher magnification of 277x - 292x and see more detail. This included the Wesley Comet Impact scar that appeared as a pronounced elongated streak in the South Polar Region.

Here is a link to the sketch:


Clear Skies,

Eric Jamison

#2 niteskystargazer



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Posted 28 December 2012 - 05:00 PM


Nice sketch of Jupiter :).




#3 frank5817



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Posted 29 December 2012 - 01:12 AM


Very nice sketching and report. I remember this impact event that summer, I sketched it too and I know Michael Rosolina (Special Ed) did as well.
Nice post Eric.

Frank :)

#4 ericj


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Posted 31 December 2012 - 09:46 AM

Hi Tom,

Thanks for the kind words.


Eric Jamison

#5 ericj


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Posted 31 December 2012 - 09:53 AM

Hi Frank,

Thanks for the kind words. It was interesting to observe and glad you were able to observe it as well.



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