How does Lepenski Vir elucidate its Archaeoastronomy?
The first archaeoastronomical surveys were conducted during the winter solstice in 2014. They pointed to the possibility of a "double sunrise" occurring during the summer solstice. The volcanic hill Trescovăț, which is located across the Danube from Lepenski Vir, has a rocky outcropping near the top and an inclination higher than the inclination of the Sun's apparent orbit. The Sun appears above Trescovăț, then goes behind the outcropping and reappears again. The phenomenon was observed and confirmed during the summer solstice of 2015. The entire passage, which was filmed, lasts slightly over 4 minutes. Scientific literature mentions two archaeological locations in Great Britain where a "double sunset" has been observed during the solstices, but a "double sunrise" has not been recorded. As the axial tilt has changed since then, a geospatial analysis was conducted using the GPS, which proved that the "double sunrise" occurred at that time as well, and that it was visible from the original location of Lepenski Vir.The phenomenon was investigated by Pavlović and Aleksandra Bajić, who published their findings in 2016 book "The Sun of Lepenski Vir". As only the specific position of the Sun during the winter and summer solstices was necessary to calculate the time using a reference point which repeats after one year, they believe that Lepenians used the "double sunrise" as a basis for some kind of a solar calendar which dated to 6300–6200 BC. As Lepenski Vir was a sedentary community for several millennia, Pavlović and Bajić hold that the inhabitants must have observed the phenomenon, especially since people were then much more observant of natural phenomena than they are today. Even Srejović, who died in 1996 and was unaware of the phenomenon, said that, based on the geographical configuration of the gorge, the "dance of light and shadows occasionally reach the levels of hierophany". The terrain was further surveyed by theodolite, and an astrogeodetic analysis was conducted in 2017. The results show that the "double sunrise" was visible from the northernmost part of the settlement.  Viewed from the southernmost part, the summer solstice Sun rose on the southern  part of the flattened top of Trescovăț. So, the whole settlement was accurately measured with respect to the astronomical event.
axial tilt Trescovăț summer solstice hierophany archaeoastronomical astrogeodetic theodolite Danube winter solstice