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Fragment A Observation Reports


Observations from Calar Alto, Spain

Impact A was observed with the 3.5m telescope at Calar Alto using the MAGIC camera. The plume appeared at about nominal position over the limb at around 20:18 UT. It was observed in 2.3 micron methan band filter brighter than Io.

Tom Herbst, Doug Hamilton, Jose Ortiz, Hermann Boehnhardt, Karlheinz Mantel, Alex Fiedler

Click here to see the Calar Alto images.

Observations from La Palma, Canary Islands 4.2m

We just finished our first observing session, very hectic. We have no obvious flashes but will go through the data carefully. The Granada people saw it at 2.3 um and the NOT (Nordic Optical Telescope here on this mountain) got it very clearly at 10 um, both imaging Jupiter.

S. Larson
H. Campins
F. Moreno
A. Molina

The impact site of fragment A is visible in images obtained with the 1m Jacobus kapteyn telescope on La Palma from 22:38 UT onwards. Related cloud disturbances are also possibly visible, including a suggestion of a partial ring-like structure (not agreed on by all observers!) expanding into surrounding belts. However if real, then the later feature appears to be centered at a lower latitude than the impact site itself.

Alan Fitzsimmons, Peter Andrews, Robin Catchpole, Phil Rudd, Nic Walton, Iwan Williams.

Tentative Visual Sighting at Wise Observatory

We obtained images of the regions around nuclei A-G in the 2 hours prior to the impact of nucleus A, but have not finished reducing the image data yet. We did not detect any obvious brightness increase of Europa. Two independent visual observations using small telescopes outside the dome report a possible sighting of a brief (less than 1 second duration) sharp flash near the limb of Jupiter and in the approximate correct location at approximately 20:04 UT (July 16).

Jim Scotti, Noah Brosch, Elia Leibowitz, John Dann, and several others from the Wise Observatory, Mitzpe Ramon Israel.

Observation from Whately Observatory

Observations from the 0.4m Whately Observatory in Western Massachusetts with the NICMASS Infrared camera have detected atmospheric features induced by impact "A". Observing in a 2.23-2.29um filter (deep in the methane band) at 00:20 UT we see a bright spot at the impact latitude about to disappear over the West limb. The spot is about 50 times fainter than Io (which just emerged from behind the planet). The feature was still visible at 01:34UT. Observers were Mike Skrutskie and Sven Aas from the University of Massachusetts.

Additional information: At 1:50 UT the impact site was no longer visible, having rotated over the limb. Unfortunately we cannot provide a more accurate timing as it was cloudy between 01:38UT (the last observation where we could see the feature) and 01:50UT.

South Pole Infrared Explorer

The South Pole Infrared Explorer (SPIREX), a 60 cm telescope, has detected the plume from fragment A at 2.36 microns. At 20:25 UT it was still brighter than Io. Brightness diminished rapidly during the next two minutes, but it remained visible at this wavelength (CO filter) for 20 minutes. Images at other wavelengths are being transferred back from the pole currently.

M. Hereld, H. Nguyen (at S. Pole Station), B. Rauscher, S. Severson Astronomy & Astrophysics Center, University of Chicago


Confirmation of very bright plume at 2.3 and 1.7 microns from impact A from CTIO. Brighter than polar caps at 2.36 microns!! Also two fainter spots visible closer to the equator visible at 1.7 microns- these might be a normal meterological phenomenon though...

John Spencer
Darren Depoy
OSIRIS, CTIO 4-meter
7/16 23:30 UT

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