Motivation for ASCOM - Why Does it Exist?

In the early days of computer-assisted astronomy, devices came with their own "computer control" (usually ASCII over RS-232).One such protocol was the so-called LX-200 standard, derived from the commands published by Meade Instruments Corporation for use with their Meade LX-200 series of telescopes. The LX-200 protocol was copied by other mount makers so their mounts would run with apps that spoke "LX200". But each mount maker eventually customized their mount's ASCII commands because their mounts had unique features, so these protocols diverged and became unique. Other high-end mounts had their own unique ASCII or TCP/IP protocols from the outset. A few kept their control protocol private and provided their own apps (software hand boxes or planetariums) completely locking out others from controlling the mount.

In the story board below you can see some of the problems. There are eight pictures in the story. There is more historical context below the story board. Take your time, these are important concepts.

First, each application had to include its own unique adapter code for each mount, written by the app developer. The poor app writers were developing special interface logic for each mount, relying on often sketchy documentation of the mount controller's protocol (and timing quirks), plus apathetic or even hostile attitudes from some mount makers. The app developer was taken away from creating the envisioned app, instead slogging away re-inventing unique control logic for every mount out there (and creating support headaches as well)! Worse, when a new mount came out, the mount maker, and the prospective users, pressured all of the app makers to add "support" (to write more special code and another support headache) for that new mount type. Must the app developers write and test more adapter code and release a new update of their apps? And what about the person who has a great idea for a new astronomy app? That developer is faced with the daunting task of writing adapter code for a whole load of mounts (and other devices) before the app can even go to market, a huge barrier to entry and innovation. And must a hapless app developer have a warehouse full of mounts in order to develop and support these things? A year from now a customer complains that the mount went wonky. Does the app developer deserve to be saddled with supporting this thing? That's how it usually went. The problems go even deeper but I'll spare you the pain.

Perhaps this will help you understand why universal standard interfaces became the norm in computers as well as virtually every other modular ecosystem back in the early 1980s, almost forty years ago. ASCOM brought a standardized ecosystem to astronomy in 1998. Now you can start to learn about the environment and design elements of ASCOM. Continue to 1. Overview of ASCOM.