Welcome to


This server runs mainly to provide a mail server that is not controlled by anyone else than me (and a hopefully uninterested netcup team).

PGP key

Hannes Riechert

key ID: 5C936AF0788A16F3
on keys.gnupg.net
as file

Tinkering & Crafting

3D stellar constellations

These are written instructions for making little 3D stellar constellations, e.g. as nerdy Christmas presents.
Instructions here ... (German text only.)

Bits and Bytes for Calliope mini

Small and not so small programs for the Calliope mini, a platform for children to make first steps in programming. There is a Snake variant and a two-player game over the in-built radio!
Programs here ... (German text only.)



Python package and scripts for analyzing geometric distortions of optical systems. This software is meant for quick-look inspection of distortion data sets exported from Zemax models. (GitHub, Documentation)

physics utilities (completely outdated)

Python module that assists in formatting physical quantities, fitting models while keeping track of quantities, and formatting results in LaTeX tables. (GitHub, quick-start guide)

Impressum / legal notice