Guide9 recognizes older observatory codes for the location.

It does not recognize my observatory code, H19, which was
obtained a few years ago. Is there a way to update the list?

What I do for find_orb and should work equally well for guide is run get_ObsCodes.sh which is:

====snip====
#!/bin/bash
wget -N http://www.minorplanetcenter.org/iau/lists/ObsCodesF.html && \
chmod 644 ObsCodesF.htm*
wget -N http://www.minorplanetcenter.org/iau/lists/ObsCodes.html && \
lynx -dump ObsCodes.html > ObsCodes.htm &&
chmod 644 ObsCodes.htm*
====snip====

It works in Cygwin. You can convert to a cmd file (leave out the chmod) if you have native Windoze versions of wget and lynx.

Andrew

-- 
There's no point in being grown up if you can't be childish sometimes.
-- Dr. Who