Hi Peter,
just FYI: There is a reason why e.g. the German Astronomical Directory GAD (https://www.sternklar.de/gad/), which lists all planetaria, public observatories and amateur associations in Germany, does not provide a map or kml file: Concerns were raised several years ago that a map that shows all the exact locations would make it very easy for burglars specialized on stealing astro equipment to find a whole list of remote but easily accessible places for their next raid. And while several of the MPC observatory codes belong to research institutes or public observatories that can be found on the internet anyway, the remaining ones are private observatories whose owners might worry about this too (or simply do not want their observatory to be featured publicly). For similar reasons (but mainly of course for much better accuracy), the MPC itself only provides a list with parallax constants which have to be converted to latitude first for a map projection. Keeping this in mind, you might want to reconsider featuring the MPC obs codes this way.
Best regards
Carolin
