In the ai.zip, there is a database with Czech and Slovak astronomical institutions. It is meant to be used as *.dbf or printed. For that purpose, there are inner and outer sides of a booklet (as PostScript files). Such a booklet contains an explanation as well. The explanation is contained also in the PDF version of the booklet, ai.pdf. Apart from ai.pdf, three other separate files are offered (in ISO Latin 2 code, of course). One containes labels to be eventually printed (just Czech institutions are contained), another is a HTML version of the whole database --- this one is definitely not meant to be printed (!), just to be viewed on the screen, and the remaining is a list of addresses that can be appended to the file .addressbook used by the "pine" programme. Two other files are e-letters to the contained institutions with e-mails. E-mails of two other institutions are different from previously mentioned: risehvezd@mbox.vol.cz and hvezdarna.pv@mbox.vol.cz. Email to Teplice planetarium did not work, as their mailbox is full. This work is just my attempt to bring a bit up to date an old database, prepared for the ``Sdruzeni hvezdaren a planetarii'' by me in 1993. It is not based on new correspondence with all the institutions, nor authorized by them, apart from some e-mails or phone calls. However, I will gladly correct the contained information, when asked by their represetnatives. Jan Hollan, August 1998