Results of Observations of 14 Mutual Events of Galilean Moons of Jupiter

1
Results of Observations of 14 Mutual Events of
Galilean Moons of Jupiter
Arto Oksanen (Nyrölä observatory,
Finland) Apostolos Christou (Armagh Observatory,
Northern Ireland)
AstroCon 2004 AL AAVSO ALPO ASP
2
PHEMU03 campaign

• In 2002-2003, the Earth and the Sun go through
  the common orbital plane of the galilean
  satellites of Jupiter.  This occurs only every 6
  years and allows the observation of mutual
  eclipses and occultations between the
  satellites.  
• These observations were made during the last
  opportunities since 1973 until the former
  campaign of 1997 and they have led to interesting
  results well in astrometry (dynamics of the
  system) as in planetology (physics of the
  surfaces of the satellites) thanks to the
  large number of data obtained on a long interval
  of time.

• Observations are easy to perform even with a
  small telescope (Galilean satellites have a
  magnitude about 5) and, in order to make them
  possible to the observers, we propose the
  information provided here.

3
Geometry of events

• Every 6 years the orbits of galilean moons align
  with Earth and Sun
• Numerous mutual eclipses and occultations

4
Eclipses and occultations
http//www.bdl.fr/Phemu03/ntph01_eng.html
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Observable events

• 105 phenomena were observable at Nyrola
  Observatory
• Sun elevation lt -10.0 deg.
• Jupiter elevation gt 10.0 deg.
• distance to the planet gt 1.0 planetary radii
• magnitude drop gt 0.010

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Table of observable events

• --------------------------------------------------
  --------------------------------------------------
  --
• Magn. Durat.
  Distance Distance Planet
  Sun
• Date of maximum(TT) to
  Right As. Declination to
• Event Drop
  planet of planet (P) Earth Az H
  Az H
• --------------------------------------------------
  --------------------------------------------------
  --
• Year m D h m s s
  (RP) h m s d ' " AU d d
  d d
• 2002 10 20 22 51 39 2 OCC 1 P 0.261 302
  5.0 9 10 48 16 48 13 5.49 -107 10 -165
  -37
• 2002 10 28 1 12 3 2 OCC 1 P 0.410 342
  5.2 9 14 13 16 34 25 5.39 -69 29 -124
  -30
• 2002 11 4 3 32 10 2 OCC 1 P 0.410 363
  5.4 9 17 7 16 22 44 5.28 -23 42 -89
  -17
• 2002 11 12 23 9 30 4 OCC 2 P 0.158 371
  6.4 9 19 58 16 11 34 5.14 -85 21 -157
  -44
• 2002 11 17 0 44 35 1 OCC 2 P 0.011 83
  1.5 9 20 59 16 7 47 5.08 -58 33 -128
  -38
• 2002 11 21 21 21 28 2 OCC 1 P 0.146 353
  5.7 9 21 56 16 4 29 5.00 -101 12 165
  -47
• 2002 11 24 2 53 0 1 OCC 2 P 0.091 156
  1.2 9 22 17 16 3 25 4.97 -12 43 -96
  -26
• 2002 11 28 21 36 22 2 ECL 1 P 0.275 245
  5.1 9 22 48 16 2 8 4.90 -92 17 169
  -49
• 2002 11 28 23 41 24 2 OCC 1 P 0.080 326
  5.8 9 22 48 16 2 7 4.89 -63 31 -147
  -46
• 2002 12 1 4 59 46 1 OCC 2 P 0.191 189
  1.0 9 22 56 16 2 0 4.86 38 39 -68
  -13
• 2002 12 5 20 18 35 3 OCC 4 P 0.431 909
  13.8 9 23 1 16 2 43 4.80 -103 11
  142 -46
• 2002 12 5 23 58 56 2 ECL 1 P 0.453 328
  5.4 9 23 1 16 2 46 4.79 -51 36 -142
  -46
• 2002 12 6 2 1 57 2 OCC 1 P 0.036 284
  5.8 9 23 1 16 2 48 4.79 -13 43 -108
  -34

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International Pro-am collaboration

• A. Oksanen (Nyrölä Observatory, Finland)
• observations
• A. Christou (Armagh Observatory, Northern
  Ireland)
• image calibration
• photometry
• IMCCE (Paris Obs, France)
• campaign coordination
• final analysis

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Observations by Arto

• V-filtered CCD-images with short exposures
• 16-inch Meade LX200 SBIG ST8XE
• Accurate timing (local ntp server)
• Short duration events (few minutes)
• Easy to find targets

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Observed events

• DATE TYPE OBS. START OBS. END SAMPLES EXPTIME FILT
  ER OBS.
• 30/12/02 2 ECL 1 203008 205902 144 (154)
  5.0 V I/II
• 30/12/02 4 OCC 3 210632 213621 180
  1.05.0 V IIIIV/I
• 06/01/03 2 ECL 1 232408 234904 400 0.5
  C I/II
• 14/01/03 2 ECL 1 021947 025334 523 (537)
  0.5 C I/II
• 16/01/03 4 OCC 2 234632 O10527 502 (604)
  1.0 V IVII/III
• 19/02/03 4 OCC 1 201929 204130 282 1.0
  V IVI/III
• 19/02/03 4 ECL 1 220025 222747 448 1.0
  V I/III
• 15/03/03 3 ECL 4 214740 223230 579 (599)
  1.02.0 R IV/III
• 17/03/03 1 ECL 3 180920 184014 560 1.0
  V III/I
• 20/03/03 1 OCC 2 234604 000000 201 1.0
  V III/III
• 25/03/03 1 ECL 3 195818 202041 250 (420)
  0.5 V IIIII/I
• 25/03/03 2 OCC 3 203718 205616 353 0.5 V
  IIIII/I
• 25/03/03 2 ECL 3 235835 002021 305 (326)
  1.0 V III/II
• 11/04/03 3 ECL 2 205323 211115 261 1.0
  V II/III
• in these cases the dataset was truncated by
  removing data points before midnight in order to
  facilitate plotting. The actual data files
  contain the full dataset.

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Beginning of an eclipse
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Photometry by dr. Christou

• Aperature photometry with IDL
• Relative flux of
• eclipsed moon vs. eclipsing moon
• occulting moon occulted moon vs. third moon
• Moons move during events
• Photometry data given to IMCCE

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Europe ecl. Io Jan 6, 2003
13
Callisto occ. Europe Jan 17, 2003
14
Ganymede ecl. Callisto Mar 15, 2003
15
Io ecl. Ganymede Mar 17, 2003
16
Europe ecl. Ganymede Mar 25, 2003
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(No Transcript)
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Mid event timings
Measured with Peranso (www.peranso.com) using
the Kwee-van Woerden method (Kwee, K., van
Woerden, H., 1956, Bulletin of the Astronomical
Institutes of the Netherlands BAN, Vol XII,
464.)
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Challenges

• Weather !
• only about 15 percentage of the events were
  observable
• Brightness of moons
• short exposure -gt scintillation -gt scatter
• Timing
• Only full seconds in FITS headers !
• Shutter delay, about 0.5 s
• 0.1 s accuracy of ntp server
• Windows, about 0.1 s accuracy
• Minimum finding with Peranso
• Assumes symmetrical light curves

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Acknowledgements

• Jenny and Antti Wihuri Foundation
• supporting the Nyrölä observatory
• AAVSO and Curry Foundation
• providing the ST8XE CCD camera

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Questions?
http//nyrola.jklsirius.fi/phemu03/

• Arto Oksanen
• tel [phone]
• arto.oksanen_at_jklsirius.fi
• http//www.ursa.fi/sirius