1. PHEMU 2015 Europe eclipse Amalthea COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

2. Ephemeris 2E5, Europe eclipse Amalthea,2015-04-08, 20h16mn33s UTC (Start). Duration: 2,7 minutes (30 images) Amalthea magnitude: 14.5 Distance between satellites: 37 arc/second Jupiter elevation : 58 ° Ideal conditions ! COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

3. Sky field map COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

4. Saint-Sulpice Observatory - IAU947 Newton Telescope Diameter: 60 cm Focal length: 336 cm …. COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

5. « Methane strategy » Jupiter absorption on Methane CH4 COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

6. Methane Filter 890nm Bandpass Interference Filter: 10nm FWHM Edmund Optics « Techspec » series. COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

7. EMCCD Raptor Camera EMCCD Camera Raptor Photonics Gain : 50 %. Recorded on Dell PC laptop(FITS files). GPS datation (Michel Chevreton Software). COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

8. First result: Amalthea detected COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

9. Photometric analysis 1 The unit images reveal of very faint signal, Amalthea is barely visible. The measurements of Amalthea is difficult with: – common software (Prism, Iris, Tangra,…) – different photometry mode (Aperture or PSF fitting) – 360 pictures on pretreated (Dark) and recentered on Callisto The results are not usable ( SNR too low). COLLOQUIUM Astrometry of the solar system after the Gaia project - PARIS Bernard Christophe, Olivier Dechambre

10. Processing and Photometry 2 360 pictures ( 5 sec) Dark processing Realigned using Callisto (Maxim DL) Sliding average on N pictures Amalthea photometry (N) Minimum of eclipse (N) Timing

11. Photometry fonction of N N= 5..\..\..\..\..\PHEMU2015\sortie05.xls..\..\..\..\..\PHEMU2015\sortie05.xls N=15..\..\..\..\..\PHEMU2015\sortie15.xls..\..\..\..\..\PHEMU2015\sortie15.xls N=21..\..\..\..\..\PHEMU2015\sortie21.xls..\..\..\..\..\PHEMU2015\sortie21.xls N=25..\..\..\..\..\PHEMU2015\sortie25.xls..\..\..\..\..\PHEMU2015\sortie25.xls N=35..\..\..\..\..\PHEMU2015\sortie35.xls..\..\..\..\..\PHEMU2015\sortie35.xls

12. Amalthea photometry (N) Amalthea curve light Rank is first image on an N packet

13. Minimum de l’eclipse fonction de N

14. Timing The middle of the PHEMU is n°153 image ( N°154 but Raptor camera started the first image at zero number) The datation of the n°153 image is 20150408 201756.8 ( Raptor camera header file displays image beguinning ) 154.14 => 20h17mn56.8s + 2.5s + 0.14*5s = 20h17mn60s The middle of the PHEMU is 2015 04 08 20h18mn00s + or - 3s

15. Conclusions : Methane filter reduces the Jupiter diffusion but also Amalthea's light… Methane filter: the Galilean moons are still very bright and can be in close proximity of Amalthea. Occultation disk ?? The functions of photometric analysis software must evolve. Example: Sliding average on N pictures. For the moment, a quite difficult observation for amateurs !