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Introduction Experimental setup Summations measurements of Baily’s bead width during contacts

IAP Eclipse meeting 30th Sept 2010. Flash spectra and contact timing at high frame rate, during the July 11th 2010 total solar eclipse observed from the atoll of Hao, French Polynesia. Introduction Experimental setup Summations measurements of Baily’s bead width during contacts

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Introduction Experimental setup Summations measurements of Baily’s bead width during contacts

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  1. IAP Eclipse meeting 30th Sept 2010 Flash spectra and contact timing at high frame rate, during the July 11th 2010 total solar eclipseobserved from the atoll of Hao, French Polynesia • Introduction • Experimental setup • Summations measurements of Baily’s bead width during contacts • Inflexion points and contacts • Measurements of intensities continuum of the last C2 and first C3 Baily’s bead during contacts • Fitting of the Baily’s beads spectra with the lunar profile • Solar edge analysis at the 3rd contact : F and emission lines • Conclusion Cyril Bazin, Serge Koutchmy, Jean Mouette, Patrick Rocher and François Sevre Institut d’Astrophysique de Paris- IAP/CNRS-UPMC & IMCCE-Obs de Paris

  2. Introduction • Contacts timing to evaluate the solar diameter thanks to solar eclipses in the context of the Picard experiment • True continuum between solar edge emission lines with flash spectra : no parasitic/scattered light from the disc • The eclipse phenomenon occurs in space : no seeing effects due to the Earth turbulence • Precise contact measurements (millisecond range) • Spatial resolution (~ 20 km) on the Sun much better than the scale height (~100 km) due to the differential angular motion of the Moon and Sun : approx 1’’/2 second • The lunar profile should be taken into account

  3. Motivation • What is the influence of emission lines superposed to F-line when defining the limb of the Sun ? • How the solar limb is defined when measuring the solar diameter ?

  4. I) Flash spectra experimental setup :high dynamic CCD Lumenera Camera of 12 bit, 15 frames/s The slit less eclipse experiment put on its equatorial mount using manual pointing Day of the 11th July total eclipse Atoll of Hao, in front of the ocean (Photo by Meleana Adams) Views of the grating 50 mm objective and removable filters

  5. Diagram of the flash spectra eclipse setup CCD Lumenera camera 12 bit – 15 frames/s Pixel size 4,6 µ USB-2 Spectral resolution : 0,012 nm/pixel Spectral range : 470,0 +/- 5,0 nm Spatial resolution (effective achieved) : 1,5’’/pixel Time effective exposure : 55,1 ms PC computer for spectra acquisition Software used : Lucam Recorder

  6. II) Summation profile of the Baily’s bead width in arcseconds 2nd contact of the 11th July 2010 total eclipse in Hao

  7. II-1) Enlargement Baily’s bead width summation profile in arcseconds 2nd contact of the 11th July 2010 total eclipse in Hao Intensity levels In log scale

  8. II-2) Enlargement Baily’s bead width Summation profile in arcseconds 3rd contact of the 11th July 2010 total eclipse in Hao - C3 He I 471,3 nm He II 468,6 nm Intensity levels In log scale

  9. II-3) Summation profile of the Baily’s bead width in arcseconds 3rd contact of the 11th July 2010 total eclipse in Hao Thicker clouds Intensity levels from 0 to 4095 adu In linear scale

  10. III) Last Baily’s bead intensity profile during the 2nd contact – C2 of the 11th July 2010 total eclipse Missing points : Images lost : -saturation of the caméra -low frame speed Last Baily’s bead 9

  11. III-1) Last Baily’s bead intensity profile during the 3rd contact – C3 of the 11th July 2010 total eclipse Missing points : realignement Last Baily’s bead

  12. III-2) Results of contact timing measurementsusing the Baily’s beads « width » measurements • 1st inflexion point 2nd contact : 18h 41 min 26, 9 +/- 0,1 s (TU, GPS time) • 2nd inflexion point 2nd contact : 18h 41 min 32,2 +/- 0,1 s (TU, GPS time) • 1st inflexion point 3rd contact : 18h 45 min 04,5 +/- 1,0 s (TU, GPS time) • 2nd inflexion point 3rd contact : 18h 45 min 08,0 +/- 0,7 s (TU, GPS time) Bad precision at 3rd contact C3 : thicker clouds

  13. IV) Fitting of the spectra and the lunar limb profile at the 2nd contact – C2 Lunar profiles from Patrick Rocher, IMCCE

  14. IV-1) Fitting of the spectra and the lunar limb profile at the 3rd contact – C3 Lunar profiles from Patrick Rocher, IMCCE

  15. Transition 3’’ 1pixel = 1,5 ‘’=0,012 nm 1125 km/pixel 1’’ = 750 km 14

  16. IV-3)Levels adjustements to show the F and emission linessummation of 5 pictures near the 3rd contact – C3 He I 471,3 nm He II 468,6 nm N° 5168 at 18h 45 and 6,2 s

  17. V) Conclusion • Solar contacts evaluations using inflexion points • Eclipse duration evaluated • True continuum between lines well estimated • Intensity continuum profiles of the last and the first Baily’s Bead during contacts : to be evaluated • New Solar edge definition : F-lines and emission lines seen simultaneously ? • Perspectives : solar diameter measurements : model of the upper layers of the solar atmosphere

  18. Bibliographic References • A great total solar eclipse on July 22 2009, by S. Koutchmy, J. Mouette and C. Bazin • Observations et Travaux, Société Astronomique de France, December 2008 , Vol 71, p 2-12 • . Poster at the Leuven (Be), solar physics conference : « Helium shell, formation and Origin », C. Bazin and S Koutchmy, April 2009 • .«Results from 2008 solar eclipse », C. Bazin, and S. Koutchmy, Suzhou China Conference, 25/07/2009, • « The chromospheric spectrum at the 1962 eclipse, Dunn », Evans and Jefferies, ApJ Supplement, 15, 275, 1968 • « The He+ 4686 A line in the low chromosphere », SP Worden, JM Beckers, T. Hirayama,, Solar Physics, Volume 28, Issue 1, pp 27-34 01/1973 • « Theoritical line intensities, Excitation of chromospheric He II and hydrogen », R.G. Athay, High Altitude Observatory, ApJ, Vol 142, p 755 08/1965 • « A model of the chromosphere from the helium and continuum emission », R.G. Athay and D. Menzel, • ApJ, vol 123, p 285 03/1956 • « Observation of prominences in He II with a new 25 cm Coronograph », T. Hirayama, Y Nakagomi, Tokyo Astronomical Observatory, Astronomical Society of Japan, vol 26, p 53 1974 • . « Model atmosphere, VAL » , Vernazza, Avrett, Loeser ApJ Suppl. Series, Vol 45, p 635 – 725 04/1981 • . « Continuum of the extreme limb and chromosphere at the 1970 eclipse », H. Kurokawa, Solar Physics, Vol 36, Issue 1, pp 69 – 70 05/1974 • . « Baily’s bead Atlas in 2005-2008 Eclipses » Sigismondi, C et Al Solar Physics, Vol 258, Issue 2 • P 191-202 • . Solar database, Bass 2000 : http://bass2000.obspm.fr/present_fr.html (visited 8th July 2009)

  19. Bibliographic References . IMCCE Ephemerides, Eclipses solaires, Rocher P. http://www.imcce.fr/fr/ephemerides/phenomenes/eclipses/soleil/index.php . « guidelines for measuring solar radius with Baily’s bead analysis » Sigismondi, C. November 2009, Science in China Series G: Physics, Mechanics and Astronomy, Volume 52, Issue 11, pp.1773 -1777 .Koutchmy, S., Vial, J-C. (1973) «Angular Dependence of the Optical Properties of a Narrow Band Interference Filter», Astronomy & Astrophysics, 25 p 145 .Françon, M. (1984) «Séparation des radiations par les filtres optiques», Masson Edition Safety while using Coronado filters and manual user guides: http://www.coronadofilters.com/pdf/Coronado_Manual_06.pdf voir également la présentation en français par J-M. Malherbe et N. Mein sur le site http://solaire.obspm.fr/pages/obs_amateur/coronado.html Bray, R.J., Loughhead, R.E. (1974) «The solar chromosphere», Chapman and Hall edition, London p 16-68 .Zirin, H. (1987) «Astrophysics of the Sun», Cambridge University Press 433 p .Athay, G. (1961) «Physics of the solar chromosphere», Interscience publishers, 384 p .Vilinga, J. (2006) «Analysis of the variations of the Solar Chromospheric Shell and its Prolateness», PhD, Pierre et Marie Curie University, ParisVI, 7th December 2006 http://www2.iap.fr/users/leboutei/JDT/Vilinga_fichiers/frame.htm .Vilinga, J., Filippov, B., and Koutchmy, S. (2007) “On the dynamic nature of the prolate solar chromosphere: jet formation” Astronomy and Astrophysics, 464, Issue 3, p 1119-1125

  20. Additional slides • PC computer time calibration with US Navy web site : • http://tycho.usno.navy.mil/simpletime.html • 9h50 TU the 27th June 2010 • 20h 50 TU the 7th July 2010 • The PC advances + 3 s on 10 days and 11 hours (903600 s) • The computer was calibrated the 8th July evening 3 days before eclipse • by substarcting 1 second in order to try to be at the exact time at the eclipse day • Next checking of the drift of the computer after eclipse : • The 27 of September at 19h 30 TU advance of + 30 s confirmed • 81 days (6998400 s) so 1 second for 2,7 days • Depend on the calibration of the US Navy time • Drift also linked with temperature

  21. II) Methods of measurements of the time difference GPS - PC • -The screen of the GPS was recorded by the same Lumenera camera used for flash spectra : • camera removed and insertion of a small focusing lens • Transition between 18h 51 min 29 s and 30 s • taken as reference. • - Using DS9 : fits headers of the image of GPS gives PC time 20

  22. III) time difference calibration : PC – GPS

  23. IV) Trying explanations of the factor 2 or 2,5 for the scale True width Image : J. Mouette 2nd contact - C2 Frame n° 2780 Alpha ~ 26 ° and sin (alpha) ~ 2 Measured width on flash spectra

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