21.   Radio telescopes collect signals that help fill in gaps left by optical instruments.

22.   The sale also includes the Keeler companies which produce optical instruments.

a. + instrument >>共 744
musical 10.71%
financial 7.73%
new 3.24%
surgical 2.73%
blunt 2.59%
scientific 2.41%
precision 2.19%
medical 1.47%
electronic 1.33%
traditional 1.29%
optical 0.79%
optical + n. >>共 201
component 4.25%
system 3.97%
scanner 3.84%
fibre 3.84%
mouse 3.29%
network 3.29%
equipment 3.01%
instrument 3.01%
networking 2.88%
technology 2.60%
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