Update: Sadly, parts of the dish have collapsed, several cables have snapped, and the Arecibo radio telescope is now decommissioned and demolition has been recommended because it is now too unsafe to do anything else.
- NSF begins planning for decommissioning of Arecibo Observatory’s 305-meter telescope due to safety concerns
- Iconic radio telescope in Puerto Rico to be demolished
Perhaps an answer now can pay tribute to Arecibo's monumental half-century contribution to science!
Although it is technically a radio telescope for astronomy and radar ranging, the Arecibo Observatory has been used for Messaging for Extra-Terrestrial Intelligence (meti). For how many total hours had Arecibo been used to transmit a signal?
If your reference source distinguishes between METI, radar, and/or other types of transmissions, please include this information in your answer.