Transient luminous event
Transient luminous events (TLEs) are various brief optical emissions between the top of the thunderclouds and the lower boundary of the ionosphere. These emissions are consequences of occasional, intensive flow of electromagnetic energy and charge in the upper atmosphere up to 90-100 km height. More details you can find here: Wikipedia
Red sprite observations
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Sprites captured on 13.6.2015 originate from a storm only several kilometers away from the observation site. The extent of sprites can be easily compared with the Cassiopeia constellation. The ß Cas (upper star in the picture) is on 27°.
Captured sprites on 17.7.2015.
Video samples
Video sequence of the captured sprites on 17.7.2015. at 22:43:27
Video sequence of the captured sprites on 17.7.2015. at 22:53:17