Impact of technological developments

Computers

Besides the telescope itself, the electronic computer has become the astronomer's most important tool. Indeed, the computer has revolutionized the use of the telescope to the point where the collection of observational data is now completely automated. The astronomer need only identify the object to be observed, and the rest is carried out by the computer and auxiliary electronic equipment.

A telescope can be set to observe automatically by means of electronic sensors appropriately placed on the telescope axis. Precise quartz or atomic clocks send signals to the computer, which in turn activates the telescope sensors to collect data at the proper time. The computer not only makes possible more efficient use of telescope time but also permits a more detailed analysis of the data collected than could have been done manually. Data analysis that would have taken a lifetime or longer to complete with a mechanical calculator can now be done within hours or even minutes with a high-speed computer.

Improved means of recording and storing computer data also have contributed to astronomical research. Optical disc data storage technology, such as the CD-ROM (compact disc read-only memory) or the WORM (write-once read-many) disc, has provided astronomers with the ability to store and retrieve vast amounts of telescopic and other astronomical data. A 12-centimetre CD-ROM, for example, may hold up to 600 megabytes of data--the equivalent of 20 nine-track magnetic tapes or 1,500 floppy discs. A 13-centimetre WORM disc typically holds about 300 to 400 megabytes of data.