Impact Site on Jupiter.

[Paul G. Abel]

Greetings everyone.

Here's my drawing of the impact site on Jupiter, alas the seeing was not good (hardly any detail in EZ) but I could make out the impact feature. It appears (to me) to be a dark elongated smudge with a dark core (intensity 9) surrounded by a light grey region (intensity 8) in the SPR.

All best wishes,

-Paul.

[barkis]

Splendid work as usual Paul.

I do like the EQ bands colouring too..

Ron.

[michaelmorris]

That's a lovely sketch.

[Talitha]

Fantastic, i knew you'd get it. Looks much the same as a sunspot's umbra and penumbra... what's the intensity scale you used? The name of it i mean, just curious.

[David Galvin]

Excellent drawing Paul and I am so pleased that you got it too. Could we (Liverpool A.S) include it in the next newsletter please. :-)

[Telescope40]

Hi There. Fantastic observation. Can you just confirm all the notes at the bottom. Understand UT and magnification but can u just clarify the rest of the notes. Thx John

[Paul G. Abel]

Thanks everyone!

David, No problem, I'll send you a copy of the drawing for your newsletter.

Telescope 40, the notes at the bottom are the longtudes of the three systems at the time of observation. Since Jupiter is not a solid world like the Earth, it rotates at different rates- the equatorial region known as System 1 (abbreviated tp omega 1 or recently to CM1 to the eternal confusion to folk like me) rotates once in 9h 50m 30s, everthing else (except the polar regions) is System 2 (CM2 or 'omega 2') rotates in 9h 55m 41s. Finally System 3 is the rotation of Jupiter's magnetosphere and the polar regions and this rotates once in 9h 55m 29s.

So all of the spots and features will lie on a longitude line of some sort (either in system 1, 2 or 3) and by making a transit time of any given feature (i.e. timing when a given feature is on the Central Meridian) we can calculate it's longitude. In fact WINJUPOS will give you the 3 longitudes in its empheredies page if you don't wish to work them out yourself.

This may sound like a lot of effort to go to but it is worth while, see if you time when a given feature is on the CM over a month or so, you will find that it's longtiude is not fixed (unlike objects here on the Earth), there will be some drift. In fact the drift in longitude is entirely due to the powerful jet streams which the feature is in. Hence measuring longitude drift rates of different features tells us a great deal about the jet streams of the atomsphere.

The final thing at the top, S=III-IV is a measure of the seeing (not how cloudy it is) but how steady the air is. The great astronomer Antoniadi devloped a scale we still use today, ANT I is perfect seeing, (presumably you get this in the deserts of America Carol? ) while ANT V is what Patrick Moore delightfully (and accurately) calls 'jellyfish seeing' (i.e. the air is so unsteady that Jupiter resembles nothing more than a steam pudding). On this observation the seeing started off as OK, then towards the end, it deteorated a bit- it wasn't quite the steam pudding scenario but it wasn't far off, hence the designation of Seeing, S=III-IV. You should always include this on your observations as it allows you to assess the quality of the observation.

Hope this helps,

-Paul.

[bish]

Great drawing. Well done for observing the impact site. I'm not sure whether I will be able to resolve it with my scope/poor eyes. It will probably be gone by the time the clouds clear here anyway!

[Jeremy Perez]

Paul, I wanted to say what a wonderfully crafted drawing this--it's such a great record of this fascinating event. Your attention to color adds even greater depth to a record that's already rich with detail. Very nice technique with the watercolor crayons!