Christian VILADRICH's home page

(last update: November 16, 2025)

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Image gallery

	Sun	Solar eclipse	Lunar eclipse	Moon full-disk	Lunar close-up	Comets	Auroras	DeepSky:
1 meter telescope Pic du Midi Observatory	Mercury	Venus	Mars	Jupiter	Saturn	Uranus	Neptune	Planet satellites

Miscellaneous topics :

• Optics :
  • Fabry-Perot etalons
  • Analysis of Fabry-Perot etalons (mica-spaced or air-spaced) for Ha solar observations
  • Selectivity of some Ca K filters
  • Sweet spot, banding and tilted etalons
  • Testing Fabry-Perot etalons and Ca K filters: methods and results (SM40, PST, SM III 60, SM III 60 RichView, etc.)
  • Telecentric assembly: principle, impact of tilt on telecentricity
  • Takahashi Mewlon 250 with 2.7×, 3.5× or 4.2× telecentrics
  • Collimating mount : f-ratio of telescope and collimator
  • Impact of FWHM on solar limb images (double limb effect)
  • Reference comparison images for the qualitative evaluation of the FWHM of Ha etalons
  • Optical systems
  • Comparison of the theoritical performance of various telescope designs (Takahashi TOA 130 & 150, Newton, Dall-Kirkham, Cassegrain-Gregory, Ritchey-Chretien, Classic Cassegrain, Schmidt-Cassegrain, Maksutov-Cassegrain) for high resolution imaging (simulations with OSLO software)
  • Simulation of the theoritical perfomance of the Celestron 14 for high resolution imaging
  • Optimisation of the Schmidt plate position in the "classic" C14 design
  • Optimisation of the Schmidt plate position in the "classic" C8 design
  • Optical performance of Takahashi Mewlon 250 CRS in white light and UV
  • Theoritical wide-field (24×36) performances of refractors (Vixen Fluorite 55 mm f/8, TS Photoline 96 mm f/6 triplet)
  • Comparison of Barlow lenses for high resolution imaging
  • Solar wedge ray-tracing
  • Spider diffraction
  • Central obstruction diffraction
  • Filter transmission profile data base
  • UV transmission of some Barlow lenses
  • Seeing and height of the telescope
• Instruments and tests :
  
  • Full-frame (24x36) coverage of various optics
  • Mesurements of D-ERF Baader filter optical quality (HASO)
  • A 300 mm Newtonian solar telescope
  • Ca K observation techniques
  • IR emission and OTA thermal balance
  • Focusing devices
  • Periodic error measurements of equatorial mountings
  • Measurement of characteristics of various CMOS cameras (e/ADU, dynamic range, linearity) : ASI 290, ASI 462, ASI 1600, Player One IMX533
  • Basler 1955-155 (IMX174) : comparison between 8 and 12 bits mode
  • Various tests (Barlow lens, MPEG/DV compression, etc)
  • Comparison of DV and MPEG2 compression for video camera acquisition
  • B/W raw webcam : influence of acquisition speed on image quality

• 2025 : Solar Imaging in Ca II - Solar Chat Meeting (in English)
• 2025 : solar high-resolution imaging at St Véran
• RCE2024 : haute résolution solaire
• RCE2024 : traitement semi-automatique des images de l'éclipse totale du Soleil d'avril 2024
• ROS2024 : methodology for measuring etalon characteristics (Ca II et Ha) - Processing solar eclipse images
• ROS2022 : methodology for measuring etalon characteristics (Ca II et Ha) - High resolution solar imaging
• RCE2021 : derniers progrès en haute résolution solaire (visible, Ca II et Ha)
• RCE2018 : haute résolution solaire en visible et proche UV
• ROS2018 : haute résolution solaire à St Véran
• RCE2016 : recent advances in high resolution solar imaging
• 2015 : a 300 mm solar telescope
• 2015 : optimisation of Ha F-P etalon
• 2015 : Solar Scintillation Monitor
• Nov 2014 : High resolution lunar imaging
• RCE Nov 2014 : High resolution lunar imaging
• RCE Nov 2014 : High resolution solar imaging part 1
• RCE Nov 2014 : High resolution solar imaging part 2
• AIP : High resolution solar imaging (June 2014)
• AIP : High resolution planetary and lunar imaging (June 2014)
• AIP : Turbulence and seeing (June 2014)
• AIP : Animation of solar imaging (June 2013)
• RCE Nov 2012 : Autostakkert 2 and high resolution solar imaging
• Serbannes - Juin 2012 : High resolution solar imaging - Presentation given at the Rencontre des Observateurs du soleil
• RCE Nov 2010 : Avistack software - Presentation given at the Rencontres du Ciel et de l'Espace - Cité des Sciences - Paris
• High resolution Ca K solar imaging (written with Serge Koutchmy - Astrophysical Institute of Paris) - Astrosurf Magazine 2010
• High resolution lunar imaging - Astrosurf Magazine - 2008

Last updates :

• 16 November 2025: measurement of the FWHM and FSR of an Heliostar 76 etalon
• 20 September 2025: test of the Acuter 40 mm
• 12 September 2025: shadow of the ozone layer seen during lunar total eclipses 7 September 2025 and 26 September 2015.
• 25 June 2025: measurement of the FWHM of the Heliostar 76
• 17 February 2005 : high-resolution Ha solar images taken on February, 16th
• 23 October 2004 : comet C/2023 A3 (Tsuchinshan-ATLAS)
• 5 October 2004 : selectivity of some Ca K filters
• 15 August 2024 : solar images taken with the 300 mm solar Newtonian at St Véran
• 8 June 2024 : update of the images of the total solar eclipse Mexico April 8, 2024 (work in progress)
• 12 May 2024 : solar images taken on May 10 and 11
• 9 March 2024 : full-disk solar images
• 15 January 2024 : image of  the earthshine taken on 18 December 2023
• 24 December 2023 : measurement of iOptron HAE29EC periodic error
• 9 December 2023 : high resolution triple-stack Ca K images taken on September 26
• 4 December 2023 : reference comparison images for the qualitative evaluation of the FWHM of Ha etalons
• 2 December 2023 : full-frame (24x36) coverage of various optics
• 1 December 2023 : measurement of characteristics of various CMOS cameras (e/ADU, dynamic range, linearity) : ASI 290, ASI 462, ASI 1600, Player One IMX533
• 20 November 2023 : high resolution solar images taken with the 300 mm solar Newtonian at St Véran on August 18, theoritical wide field (24×36) performance of some refractors
• 1 November 2023 : images of October 14, 2023 annular solar eclipse
• 19 september : measurement of transmission of various Barlow lenses and ADC
• 5 September 2023 : high resolution solar images taken with the 300 mm solar Newtonian at St Véran,
• 4 September: transmission curves of various filters, Quark Combo test
• 24 Aujust 2023 : transmission curve of various Barlow lenses from 300 to 1000 nm

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