I can not see how this device would give any new insights of radion below 400 nm??? According to the manufacturer specification the Apogee MQ-650 has a range of 400-750 nm (?) while the MQ-510 goes slightly lower (389 to 692 nm) and the MQ-210X even lower (370 to 650 nm). BUT... according to the graph the MQ-650 and MQ-510 would go equally low.
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