Hungary’s level marker
The travelling astronomer is now in Budapest, Hungary. So far I have not been near any astronomical observatories, but I hope to get to one or two next week. There has been one interesting and relevant site though.
In Australia maps indicate heights above sea level. What happens in a land-locked country? The answer is the marker in the village of Nadap on the hills above Lake Velencei, about 45 km from the capital city, Budapest. That position was not chosen randomly but because the geology of the area is exceptionally stable. The pictured marker was installed in 1888 showing the level of the Adriatic Sea. There is another marker nearby that was installed in 1951 and shows the level of the Baltic. Al least until recently all heights in Hungary were measured in relation to these markers.
For the edification of anyone interested the marker is known in Hungarian as: “Nadapi Szintezési Ősjegy”.