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The Plate Scale of the SODISM Instrument and the Determination of the Solar Radius at 607.1 nm

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Knowledge of the Solar Diameter Imager and Surface Mapper (SODISM) plate scale is a fundamental parameter for obtaining the solar radius. We have determined the plate scale of the telescope on the ground and in flight onboard the Picard spacecraft. The results show significant differences; the main reason is that the conditions of observation are not the same. In addition, the space environment has an impact on the performance of a metrology instrument. Therefore, calibration in space and under the same conditions of observation is crucial. The transit of Venus allowed us to determine the plate scale of the SODISM telescope and hence the absolute value of the solar radius. The transit was observed from space by the Picard spacecraft on 5 – 6 June 2012. We exploited the data recorded by SODISM to determine the plate scale of the instrument, which depends on the characteristics of optical elements (mirrors, filters, or front window). The mean plate scale at 607.1 nm is found to be 1.0643 arcseconds pixel−1 with 3×10−4 RMS. The solar radius at 607.1 nm from 1 AU is found to be equal to 959.86 arcseconds.

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  1. Auchère, F., DeForest, C.E., Artzner, G.: 2000, In-flight determination of the plate scale of the extreme-ultraviolet imaging telescope. Astrophys. J. Lett. 529, L115 – L117. doi: 10.1086/312471 .

  2. Capitaine, N., Wallace, P.T., Chapront, J.: 2003, Expressions for IAU 2000 precession quantities. Astron. Astrophys. 412, 567 – 586. doi: 10.1051/0004-6361:20031539 .

  3. Duda, R.O., Hart, P.E.: 1972, Use of the Hough transformation to detect lines and curves in pictures. Commun. ACM 15(1), 11 – 15. doi: 10.1145/361237.361242 .

  4. Emilio, M., Kuhn, J.R., Bush, R.I., Scholl, I.F.: 2012, Measuring the solar radius from space during the 2003 and 2006 Mercury transits. Astrophys. J. 750, 135. doi: 10.1088/0004-637X/750/2/135 .

  5. Fienga, A., Manche, H., Laskar, J., Gastineau, M.: 2008, INPOP06: a new numerical planetary ephemeris. Astron. Astrophys. 477, 315 – 327. doi: 10.1051/0004-6361:20066607 .

  6. Haberreiter, M., Schmutz, W., Hubeny, I.: 2008, NLTE model calculations for the solar atmosphere with an iterative treatment of opacity distribution functions. Astron. Astrophys. 492, 833 – 840. doi: 10.1051/0004-6361:200809503 .

  7. Hestroffer, D., Magnan, C.: 1998, Wavelength dependency of the solar limb darkening. Astron. Astrophys. 333, 338 – 342.

  8. Hough, V., Paul, C.: 1962, Method and means for recognizing complex patterns. .

  9. Meftah, M., Hochedez, J.-F., Irbah, A., Hauchecorne, A., Boumier, P., Corbard, T., Turck-Chièze, S., Assus, P., Bertran, E., Bourget, P., Buisson, F., Chaigneau, M., Damé, L., Djafer, D., Dufour, C., Etcheto, P., Ferrero, P., Hersé, M., Marcovici, J.-P., Meissonnier, M., Morand, F., Poiet, G., Prado, J.-Y., Renaud, C., Rouanet, N., Rouzé, M., Salabert, D., Vieau, A.-J.: 2013, PICARD SODISM, a space telescope to study the Sun from the middle ultraviolet to the near infrared. Solar Phys., submitted. arXiv:1303.0731 .

  10. Seidelmann, P.K.: 1992, Explanatory Supplement to the Astronomical Almanac. A Revision to the Explanatory Supplement to the Astronomical Ephemeris and the American Ephemeris and Nautical Almanac.

  11. Shapiro, A.I., Schmutz, W., Schoell, M., Haberreiter, M., Rozanov, E.: 2010, NLTE solar irradiance modeling with the COSI code. Astron. Astrophys. 517, A48. doi: 10.1051/0004-6361/200913987 .

  12. Shimizu, T., Katsukawa, Y., Matsuzaki, K., Ichimoto, K., Kano, R., Deluca, E.E., Lundquist, L.L., Weber, M., Tarbell, T.D., Shine, R.A., Sôma, M., Tsuneta, S., Sakao, T., Minesugi, K.: 2007, Hinode calibration for precise image co-alignment between SOT and XRT (2006 November – 2007 April). Publ. Astron. Soc. Japan 59, 845.

  13. Thuillier, G., Dewitte, S., Schmutz, W.: 2006, Simultaneous measurement of the total solar irradiance and solar diameter by the PICARD mission. Adv. Space Res. 38(8), 1792 – 1806. doi: 10.1016/j.asr.2006.04.034 .

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Picard is a mission supported by the Centre National d’Etudes Spatiales (CNES), the CNRS/INSU, the Belgian Space Policy (BELSPO), the Swiss Space Office (SSO), and the European Space Agency (ESA). We thank CNES, and CNRS (Centre National de la Recherche Scientifique) for their support, as well as all participants providing their expertise to this study (P. Boumier, M. Rouzé, F. Sella, S. Turck-Chièze). We wish to express our gratitude to Patrick Rocher (IMCCE, France), who participated in the calculation of the ephemeris. The authors thank the referees for the constructive remarks and suggestions.

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Correspondence to M. Meftah.

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Meftah, M., Hauchecorne, A., Crepel, M. et al. The Plate Scale of the SODISM Instrument and the Determination of the Solar Radius at 607.1 nm. Sol Phys 289, 1–10 (2014).

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  • Instrumentation and data management
  • Instrumental effects
  • Center-limb observations
  • Solar diameter