Three of James Webb’s four instruments are now aligned

The long process of getting the James Webb Space Telescope ready to begin collecting science data continues, and the team has met another goal with the alignment of three out of its four instruments. The telescope's large primary mirror makes it necessary for the alignment process to make small adjustments to each instrument to make sure they are in the right place. A few weeks ago the telescope's mirrors were aligned with its main camera and now the telescope's other instruments are being adjusted.

The Near-Infrared Slitless Spectrograph, the Near-Infrared Camera, and the Fine Guidance Sensor are near-infrared instruments. The instrument takes longer to align because it uses a different type of sensor, which has to be cooled to a very low temperature. MIRI is still in the process of being cooled down to its operating temperature, and once it reaches this milestone, it too can be aligned.

The telescope's secondary mirror, a smaller round mirror on the end of a boom arm, was to be adjusted during the alignment process for the first three instruments. They will wait until MIRI is fully cooled before making any final changes to the secondary mirror, because their alignments were so accurate.

Coarse and fine corrections are the starting points for the commission process. The fine corrections in the first iteration of Phase Six were unnecessary because the early secondary mirror coarse corrections were so successful.

There will be a second multi-instrument alignment phase once MIRI is cooled and all four instruments are aligned. The team will be able to calibrate the instruments this summer once alignment is complete.

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