| Description: | The optical throughput of the MPL at Nauru is below an acceptable level. Despite an
extended stay to address the problem in Feb 2003, the problem was unresolved. An additional
repair was attempted in July 2003 with no significant success. Several optical components
were replaced and the system was repeatedly re-aligned.
The system appears to have been properly collimated as the shape of the signal is
appropriate for both near and far range. The magnitude of the signal was simply too low. This
signal decrease was apparent in ambient background values as well as from atmospheric
signal, so the impact on data quality was not as severe as might otherwise be the case. The
MPL was still capable of detecting high altitude cirrus (day and night) but the
sensitivity was reduced. |