The paper considers various technologies of alignment of rotary kilns in their operation mode. It gives the theory of mathematical processing of rotary machines measurements with the help of electromagnetic emission and the influence of refraction onto their accuracy. The research showed that the technology of measuring along the kiln shell can contain significant errors, caused by refraction in horizontal section due to big temperature gradients. The technology, when the observing beam goes perpendicular to the kiln shell, is practically unresponsive to the influence of refraction. The paper considers the tasks, which demand further research and refinement.