One is the wide-field planetary faint-object camera developed by the California Institute of Technology and the Jet Propulsion Laboratory.

But the wide-field and planetary camera that was to perform 40 percent of the craft's scientific work will not be useable.

The wide-field and planetary camera, which would supply most of the images for astronomers to examine, will not be useable, he said.

To create microform media, a planetary camera is mounted with the vertical axis above a copy that is stationary during exposure.

At that time, the main instrument, called the wide-field planetary camera, will be replaced with an updated version that has corrective mirrors to refocus the light.

It's a beautiful, spanking new wifpic," Dr. Hoffman exclaimed, using the project's nickname for the wide-field planetary camera.

Until then, the wide-field and planetary camera, which was to bear the observational brunt of the mission, is virtually useless.

In tests over the last few weeks, astronomers determined first that the replacement wide-field planetary camera had fully compensated for the Hubble telescope's flawed primary mirror.

On the sixth and seventh days, they are to install the wide-field planetary camera and then Costar.

Until then, however, most of the observations involving the wide-field and planetary camera will have to be deferred.