Jupiter, Impact Scar, Callisto, and Shadow Transit – JUL 23, 2009 09:00 UT

Sketch of Jupiter, Callisto, Impact Scar and Shadow Transit

Sketch of Jupiter, Callisto, Impact Scar and Shadow Transit

Click image to view larger version.

Observation Notes:

Jupiter put on a great show tonight!

The impact feature is still hanging on and was readily visible through my 8 inch Dob at 120X and 240X. The best part was the addition of a beautiful shadow transit with Callisto hanging just outside Jupiter’s following limb. It also provided a nice contrast for comparison of the two spots. Callisto’s shadow was strikingly black, while the impact scar appeared more as a soft feature that seemed to take on the brownish color of the surrounding clouds. I spent more time getting a feel for the impact site itself, and did detect a horizontal elongation and slightly condensed appearance.

I had a couple moments of incredibly good seeing that showed up a lighter patch north of the impact scar and corresponded well to the position of a white spot in the area. I did not detect this as a hard oval, just as a subtle brightening in the area. Midway through my observation, high clouds moved in and foiled my attempts to finish up detail on the preceding edge before it rotated out of view, so the equatorial belts are a little plain in that part of the sketch. I finished the observation just as Callisto was dipping into Jupiter’s profile. What a great view!

Subject Jupiter, Callisto, Impact Scar and Shadow Transit
Classification Planet
Position* Capricornus [RA: 21:49:16.7 / Dec: -14:15:27]
Size* 48 arcseconds (Equatorial diameter)
Brightness* -2.8
Date/Time JUL 23, 2009, 2:00 – 3:30 AM
(JUL 23, 2009, 09:00 – 10:30 UT)
Observing Loc. Flagstaff, Arizona, USA – Home
Instrument Orion SkyQuest XT8 Dobsonian (203 mm dia./1200 mm F/L)
Eyepieces/Mag. Pentax XW10 + 2X Barlow (240X)
Conditions Mostly clear, occasional high clouds, humid
Seeing Ant. II-III
Transparency Mag 5.8 NELM
*Sources Starry Night Pro Plus 5.8.2

6 Replies to “Jupiter, Impact Scar, Callisto, and Shadow Transit – JUL 23, 2009 09:00 UT”

  1. Thanks for the sketching!! I was doing simpler doodles Wed. night/Thursday morning at the same time also with an Orion XT8 (at Nebraska Star Party at Merritt Reservoir , near Valentine, NE.)
    We never did find the impact site but had fun watching and sketching the transit. First time I had see this much detail on the planet. I can see I need to keep an eye out for better e/p!

  2. Thank you both!
    If the seeing is really soft, the details might only jump into view for the merest of moments. It certainly can be a challenge to compile those moments into a full picture, but sketches–even the most basic doodles–really do offer a great way to be sure you take in and remember as much as you can.
    Aaron, the stunning HST image from July 23 does show it starting to spread out, but it looks like it’s still got some life left in it. It will be interesting to see if we can still spot it when it smears into a band.

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