Natural satellites mutual phenomena observations: Achievements and future

New Positions of Triton Based on Gaia DR2 and New Image-processing Methods

We present a methodology to analyse and interpret a set of telescopic observations of the mutual orbital phenomena between Jupiter's Galilean satellites (occultation and eclipses) as a practical teaching tool for photometry and astrodynamic studies in astronomy courses. The mutual phenomena we describe took place in 2014 and 2015 and the observations were obtained using a 28 cm aperture telescope and a video camera. We introduce simple models to explain occultation and eclipses of the events, and offer the data and the software for their analysis.

Using Galilean satellites’ mutual orbital events as an educational tool for studies of orbital dynamics

The 2014-2015 Brazilian mutual phenomena campaign for the Jovian satellites and improved results for the 2009 events

/pdf/the-photometric-observation-of-the-quasi-simultaneous-mutual-2axw7pow.pdf

The photometric observation of the quasi-simultaneous mutual eclipse and occultation between Europa and Ganymede on 22 August 2021

Aims. During the 2014–2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies.Methods. We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction.Results. We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These observation accuracies largely override standard astrometric measurements. The (O − C)s for the eclipse of Thebe are 75 mas on the X -axis and 120 mas on the Y -axis. The (O − C)s for the total eclipses of Amalthea are 95 mas and 22 mas, along the orbit, for two of the three events. Taking into account the ratio of (O − C) to precision of the astrometric results, we show a significant discrepancy with the theory established by Avdyushev and Ban’shikova in 2008, and the JPL JUP 310 ephemeris.

/pdf/eclipses-of-the-inner-satellites-of-jupiter-observed-in-2015-42enc44pyj.pdf

Eclipses of the inner satellites of Jupiter observed in 2015

The Phemu 2015 campaign of observations of the mutual events of the Galilean satellites of Jupiter

During the 2014-2015 campaign of mutual events, we recorded ground-based photometric observations of eclipses of Amalthea (JV) and, for the first time, Thebe (JXIV) by the Galilean moons. We focused on estimating whether the positioning accuracy of the inner satellites determined with photometry is sufficient for dynamical studies. We observed two eclipses of Amalthea and one of Thebe with the 1 m telescope at Pic du Midi Observatory using an IR filter and a mask placed over the planetary image to avoid blooming features. A third observation of Amalthea was taken at Saint-Sulpice Observatory with a 60 cm telescope using a methane filter (890 nm) and a deep absorption band to decrease the contrast between the planet and the satellites. After background removal, we computed a differential aperture photometry to obtain the light flux, and followed with an astrometric reduction. We provide astrometric results with an external precision of 53 mas for the eclipse of Thebe, and 20 mas for that of Amalthea. These observation accuracies largely override standard astrometric measurements. The (O-C)s for the eclipse of Thebe are 75 mas on the X-axis and 120 mas on the Y-axis. The (O-C)s for the total eclipses of Amalthea are 95 mas and 22 mas, along the orbit, for two of the three events. Taking into account the ratio of (O-C) to precision of the astrometric results, we show a significant discrepancy with the theory established by Avdyushev and Ban'shikova in 2008, and the JPL JUP 310 ephemeris.

/pdf/eclipses-of-the-inner-satellites-of-jupiter-observed-in-2015-42z7z161jr.pdf

E. Saquet

Papers

Eclipses of the inner satellites of Jupiter observed in 2015

The Phemu 2015 campaign of observations of the mutual events of the Galilean satellites of Jupiter

Eclipses of the inner satellites of Jupiter observed in 2015