Elevation 1" arc

[nordlicht]

but it's not always easy to find elevation european data in HGT

It's straight forward as HGT is NASA's standard format for the SRTM dataset:

https://dds.cr.usgs.gov/srtm/version2_1/SRTM1/

SRTM elevation data in other formats is converted from NASA data.

As one of several alternatives for Europe you have:

http://viewfinderpanoramas.org/dem1d.html
http://viewfinderpanoramas.org/Coverage%...s_org1.htm

At least Global Mapper can also write HGT files.