Annual meeting of the Astronomische Gesellschaft, September 1995, Bonn, Germany Implications of Light Metals (Li - Ca) on NLTE Model Atmospheres for Hot Stars Workshop on Supersoft X-Ray Sources, February 1996, Garching, Germany NLTE Analysis of Central Stars of Highly Excited Planetary Nebulae IAU Symposium No. 180, Planetary Nebulae, August 1996, Groningen, The Netherlands Implications of Light Metals (Li - Ca) on NLTE Model Atmospheres of Compact Hot Stars Annual meeting of the Astronomische Gesellschaft, September 1996, Tübingen, Germany Analysis of IUE spectra with NLTE model atmospheres Ultraviolet Astrophysics - Beyond the IUE Final Archive, November 1997, Sevilla, Spain Improved NLTE Model Atmospheres for the Analysis of Hot Compact Stars Second Oak Ridge Symposium on Atomic & Nuclear Astrophysics, December 1997, Oak Ridge, TN, USA NLTE Model Atmospheres for Extremely Hot Compact Stars IAU Symposium 195, Highly Energetic Physical Processes and Mechanisms for Emissions from Astrophysical Plasmas , July 1999, Bozeman, USA NLTE Model Atmospheres for Central Stars of Planetary Nebulae Asymmetrical Planetary Nebulae II: From Origins to Microstructures , August 1999, MIT, Cambridge, USA Survey of Large Planetary Nebulae in Decay Asymmetrical Planetary Nebulae II: From Origins to Microstructures , August 1999, MIT, Cambridge, USA NLTE model atmospheres for post-AGB stars The Fourth Tetons Conference, Galactic Structure, Stars and the Interstellar Medium , May 28 - June 1 2000, Jackson Hole, Wyoming, USA Calculation of Synthetic Ionizing Spectra for Planetary Nebulae IAU Symposium 209: Planetary Nebulae: Their Evolution and Role in the Universe, November 19 - 23, 2001, Canberra, Australia The Enigma of AA Dor IAU Colloquium 215, Stellar Rotation , November 2002, Cancun, Mexico The Rotational Velocity of hot Pre-White Dwarfs IAU Colloquium 215, Stellar Rotation , November 2002, Cancun, Mexico NLTE Spectral Analysis of Central Stars of PN Interacting with the ISM Asymmetric Planetary Nebulae III: Winds, Structure, and the Thunderbird , July 28 - August 1 2003, Mt. Rainier National Park, Seattle, USA AA Dor - An Eclipsing sdOB - Brown Dwarf Binary IAU Colloquium 194, Compact Binaries in the Galaxy and beyond , November 2003, La Paz, Mexico On the Velocity Field and the 3D Structure of the Galactic Soccer Ball Abell 43 International Conference on Planetary Nebulae as Astronomical Tools , June 2005, Gdansk, Poland FUV Spectroscopy of the Central Star of Sh 2-216 Space Astronomy: The UV window to the Universe , May 2007, El Escorial, Spain Search for Mass-Ejections from Late He-Shell Flash Stars Asymmetrical Planetary Nebulae V: The Shaping for Stellar Ejecta , June 2010, Bowness on Windermere, England Jurassic World: The Decline of the Blackbody Asymmetrical Planetary Nebulae VII, Dezember 2017, Hong Kong TheoSSA: Synthetic Stellar Spectra on Demand - The Geier Grids 9th Meeting on Hot Subdwarfs and Related Objects (sdOB9), Hendaye, France, June 23–27, 2019