Observing Plans

Current Observing Plans

February, 2025 -- LIGO's fourth observing run has been extended and is now expected to conclude in October, 2025. This extension will thus yield approximately the same amount of calendar observing time as was planned with the previous June 2025 end date, after accounting for the time lost from a planned April/May 2025 break, plus that lost from unplanned interruptions in 2024.

Current (as of June 2024) timeline for the O4 observing run

For more information on LIGO/Virgo/KAGRA observing plans for O4, please see IGWN Observing Plans, and for a longer term outlook, please visit

LIGO/Virgo/KAGRA Statement on Near-term Observing Plans

Future Observing Plans

Plans are currently under development by LIGO to chart a path for interferometer upgrades and observing periods beyond O5 and continuing into the next decade.

LIGO Laboratory Statement on Long-term Future Observing Plans