diese Nachricht bekam ich von Nils Kloth ( www.astrogarten.de ), der sie mir weitergeleitet hat. Bei gutem Wetter dürfte das für einige interessant werden!
Alles Gute,
Martin
-----Ursprüngliche Nachricht-----
Von: ccd_list-owner@mail.naa.net [mailto:ccd_list-owner@mail.naa.net]Im
Auftrag von Robert
Gesendet: Freitag, 13. Dezember 2002 18:53
An: ccd_list@mail.naa.net
Betreff: CCD: Tethys Bedeckung am Sonntag, 15.12.2002, ca. 20h MEZ
Hallo !
Wer eine Minitron oder eine ähnlich lichtstarke Videokamera sein eigen
nennt, sollte dieses seltene Ereignis beobachten (siehe unten).
Möglicherweise kann damit eine dünne Atmosphere dieses Saturnmondes
nachgewiesen bzw. ausgeschlossen werden, ganz zu schweigen von den
astrometrischen Daten. Eine genaue Funkzeit sollte eingeblendet sein.
mfG
Robert Schulz
> ----- Original Message -----
> From: "Ron Baalke" baalke@zagami.jpl.nasa.gov>
> To: "Jupiter List" jupiter_list@yahoogroups.com>
> Sent: Friday, December 13, 2002 6:44 PM
> Subject: [jupiter_list] Upcoming Tethys Occultation
>
>
> >
> > Forwarded from J. Lecacheux (jlx@meteores.net)
> > Subject: Coming occn. by the saturnian satellite TETYHS
> >
> >
> > >From J.Lecacheux (France):
> >
> >
> > The saturnian satellite III (TETHYS) will occult a 9.1
> > magnitude TYC-2 star during 40 sec. next Sunday evening.
> >
> > The initial path, first computed by D.Herald last year,
> > crossed s.China, Himalayan countries, Middle and Near
> > East, and the n.African deserts. After that the Tethys
> > occultation remained almost forgotten during one year,
> > apparently eclipsed within the agenda of many observers
> > by the top-priority Pluto events of last summer.
> >
> > But surprisingly Jan Manek published 4 days ago an
> > updated prediction, showing that the shadow of Tethys
> > probably will make a central hit upon west Europe,
> > from Baltic republics to Atlantic coast of France.
> > Details are in Manek's web page :
> > http://sorry.vse.cz/~ludek/mp/updates/1215tet.html
> >
> > The diameter of Tethys is ~1060 km, and the projected
> > ground path will be ~1280 km wide (NB: Manek quoted
> > 530 and 640 km erroneously, but his calculations and
> > the world map in his page are correct).
> >
> > The lateral uncertainty of the prediction might reach
> > +/-1000 km. So any country from n.Europe to s.Europe
> > (and even in n.Africa) could be concerned, plus many
> > regions in the former Soviet Union.
> >
> > In consequence any observer of IOTA-ES or EAON, any
> > [planoccult] reader, ideally should be ready to
> > observe !
> >
> > Especially those who gained experience observing the
> > stellar occultation by the satellite III of Uranus
> > (Titania) in 2001 september are urged to contribute
> > again.
> >
> >
> > Bruno Sicardy of Paris Observatory wrote to us the
> > following message this afternoon :
> >
> > >****** Occultation by Tethys on 15 Dec. 2002 around 19:00 UT ********
> > >
> > > - Star coordinates (TYC 1310-2435-1, V=9.2, B=10.5) taken from Vizier:
> > > vizier.u-strasbg.fr/cgi-bin/VizieR-5?-out.add=.&-out.add=
> > > _RAJ2000,_DEJ2000&-source=I/259/tyc2&recno=281751
> > > with proper motion taken into account on 15 December 2002:
> > >
> > > ra = 05 41 33.8871
> > > dec= 22 03 31.214 (J2000)
> > >
> > > with typical errors of 20 mas ~ 120 km at Tethys.
> > >
> > > - Tethys ephemeris: JPL Horizon with no corrections.
> > >
> > > Two maps
> > > show the track of the shadow on the Earth,
> > > with assumed radius of Tethys 524 km. The dots on the central line
> > > are plotted every minute and the shadow is moving from right to
> > > left on the diagram.
> > >
> > > Note that the track is shifted by about half a Tethys radius to
> > > the South wrt to the predictions by Jan Manek
> > > (http://sorry.vse.cz/~ludek/mp/updates/1215tet.html).
> > > Maybe due to a slightly different star position?????
> > >
> > > Bruno Sicardy, 12 December 2002
> > ***********************************************************************
> >
> >
> > The coming occultation might be important to verify
> > again that Tethys has no significant atmosphere.
> > It is well known that stellar occultations are very
> > sensitive probes of atmospheric traces at the surface
> > of occulting bodies. The more is far an occulting
> > body, the more is efficient the method. At saturnian
> > distance sensitivity usually can approach one
> > microbar.
> >
> > But please remember that only electronic detectors
> > with photometric ability, good time resolution, and
> > of course operated in excellent observing conditions,
> > can measure such a pressure upper limit.
> > Indeed only well-calibrated immersion and emersion
> > light curves contain the needed refractive signature.
> >
> > Elementary visual timings, or uncalibrated video with
> > heavy noise, permit to refine path location (thus
> > saturnian system astrometry) with a few kilometers
> > accuracy, but have no potential for atmospheric
> > sensing.
> >
> >
> > Former observers of the 2001 Titania event should
> > note that observing the Tethys occultation will be
> > a lot more difficult.
> > There are four main reasons :
> > 1- The target star will be fainter by 2 magnitudes,
> > i.e. +9 instead of +7.
> > 2- The glare from the nearby planet (and principally
> > from its rings) will be by far more penalizing.
> > 3- A faster occultation (only 40s) than Titania's one.
> > 4- Due to the brightness of Tethys (magnitude +9.
,> > the amplitude of the occultation will be only 1.2
> > magnitude (i.e. the flux will drop from level 1 to
> > level 0.33 at immersion, then rise to 1 again at
> > emersion), whereas Titania was almost negligible
> > during the totality phase.
> >
> > Favourable characteristics are
> > 1- Continental path through very populous countries
> > (so all the virtual potential of IOTA-ES and EAON
> > should be mobilized from East Russia to Atlantic
> > coasts).
> > 2- Occurrence at pleasant hour (19h UT, late enough
> > after sunset, early enough before midnight).
> > 3- No need to move (thus favouring large telescopes
> > at fixed locations).
> > 4- Altitude above horizon better for Europeans than
> > during the past Titania event.
> > 5- Easy comparison of the target with the bright
> > nearby satellites Rhea (magnitude 9.4) or
> > Enceladus.
> >
> > ******
> >
> > Meteo forecasts at -72 h give anticyclonic conditions
> > in Russia, Belarus and Baltic republics, also chances
> > of clear sky in central Europe (Poland, Slovakian
> > republic, e.Hungary,...), then a secondary cloud
> > break in n.Italy, s.France and ne.Spain.
> >
> >
> > Clear sky to everybody.
> >
> >
> >
> > Jupiter_list home page - http://groups.yahoo.com/group/jupiter_list
> > The Moderator of this list is Jason Perry. You can contact him at
> perry@jupiter.lpl.arizona.edu
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
>
>