@ARTICLE{Wittel2014, title = {{T}hermal correction of astigmatism in the gravitational wave observatory {GEO} 600}, status = {}, author = {Wittel, H., Lueck, H., Affeldt, C., Dooley, K. L., Grote, H., Leong, J. R., Prijatelj, M., Schreiber, E., Slutsky, J., Strain, K., Was, M., Willke, B. and Danzmann, K.}, journal = {Classical and Quantum Gravity}, volume = {31}, pages = {065008}, year = {2014}, }