Many modern catalogues and/or observing lists are too large for easy printing in a magazine, or have too short a life to be economically worth printing as a catalogue or a book. We have therefore two ways of presenting them:

• (a) on microfiche

• (b) on tape (or diskette).

One could add computer print-outs, but by experience there are mostly made for private use.

Microfiches have never become very popular, although they are quite handy for long catalogues. The Henry Draper catalogue, weighting 10 kgs occupies 14 microfiches weighting 42 grams and can be accommodated in a common envelope. Durability of good microfiches is guaranteed for several decades and its price is cheap. Except thus for the reading device, which is bulky, the microfiche is a handy way to store information, especially when only small amounts of information are to be retrieved.