Hubble's systems checked; 'science verification phase' begins

WASHINGTON - The job took six months instead of three, but NASA is nearly finished checking out the various systems on the Hubble Space Telescope and is preparing its instruments for science use.

The "science verification phase" will run into next year. It involves comparing the Hubble's pictures of stars taken above the atmosphere with photos taken from the ground. That enables astronomers to adjust readings from the Hubble's five instruments.

During the orbital verification phase now nearing completion, the National Aeronautics and Space Administration discovered that one of the telescope's mirrors was ground to the wrong specifications and that the spacecraft develops an annoying shudder whenever it passes from sunlight to darkness.