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1 Introduction Experimental setup Summations measurements of Bailys bead width during contacts Inflexion points and contacts Measurements of intensities.

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Presentation on theme: "1 Introduction Experimental setup Summations measurements of Bailys bead width during contacts Inflexion points and contacts Measurements of intensities."— Presentation transcript:

1 1 Introduction Experimental setup Summations measurements of Bailys bead width during contacts Inflexion points and contacts Measurements of intensities continuum of the last C2 and first C3 Bailys bead during contacts Fitting of the Bailys beads spectra with the lunar profile Solar edge analysis at the 3rd contact : F and emission lines Conclusion 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 Cyril Bazin, Serge Koutchmy, Jean Mouette, Patrick Rocher and François Sevre Institut dAstrophysique de Paris- IAP/CNRS-UPMC & IMCCE-Obs de Paris IAP Eclipse meeting 30th Sept 2010

2 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 ? 3

4 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 5 Diagram of the flash spectra eclipse setup 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 Software used : Lucam Recorder USB-2 CCD Lumenera camera 12 bit – 15 frames/s Pixel size 4,6 µ PC computer for spectra acquisition

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

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

8 8 Intensity levels In log scale II-2) Enlargement Bailys 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

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

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

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

12 12 III-2) Results of contact timing measurements using the Bailys 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 13 IV) Fitting of the spectra and the lunar limb profile at the 2 nd contact – C2 Lunar profiles from Patrick Rocher, IMCCE

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

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

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

17 17 Solar contacts evaluations using inflexion points Eclipse duration evaluated True continuum between lines well estimated Intensity continuum profiles of the last and the first Bailys 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 V) Conclusion

18 18 Bibliographic References A great total solar eclipse on July , by S. Koutchmy, J. Mouette and C. Bazin Observations et Travaux, Société Astronomique de France, December 2008, Vol 71, p Poster at the Leuven (Be), solar physics conference : « Helium shell, formation and Origin », C. Bazin and S Koutchmy, April «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 A line in the low chromosphere », SP Worden, JM Beckers, T. Hirayama,, Solar Physics, Volume 28, Issue 1, pp /1973 « Theoritical line intensities, Excitation of chromospheric He II and hydrogen », R.G. Athay, High Altitude Observatory, ApJ, Vol 142, p /1965 « A model of the chromosphere from the helium and continuum emission », R.G. Athay and D. Menzel, ApJ, vol 123, p /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 « Model atmosphere, VAL », Vernazza, Avrett, Loeser ApJ Suppl. Series, Vol 45, p 635 – /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. « Bailys bead Atlas in Eclipses » Sigismondi, C et Al Solar Physics, Vol 258, Issue 2 P Solar database, Bass 2000 : (visited 8th July 2009)

19 19. IMCCE Ephemerides, Eclipses solaires, Rocher P. « guidelines for measuring solar radius with Bailys bead analysis » Sigismondi, C. November 2009, Science in China Series G: Physics, Mechanics and Astronomy, Volume 52, Issue 11, pp 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: voir également la présentation en français par J-M. Malherbe et N. Mein sur le site Bray, R.J., Loughhead, R.E. (1974) «The solar chromosphere», Chapman and Hall edition, London p 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, 7 th December 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 Bibliographic References

20 20 Additional slides I)PC computer time calibration with US Navy web site : 9h50 TU the 27th June h 50 TU the 7th July 2010 The PC advances + 3 s on 10 days and 11 hours ( 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 ( s) so 1 second for 2,7 days Depend on the calibration of the US Navy time Drift also linked with temperature

21 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 22 III) time difference calibration : PC – GPS

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


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