On a display on the Defiant
A long range sensor scan or long range scan is a scan which allows the person to search a large area in space for something like starships.
In 2151, Captain Jonathan Archer ordered Lieutenant Reed to stay on their long range scanners and let him know when the Enterprise made another contact with the unidentified aliens. (ENT: "Silent Enemy")
In 2367. Lieutenant Commander Geordi LaForge stated that the long range sensors aboard the Enterprise-D were able to scan a radius of ten light-years within a 24-hour period; effectively, one sector per day. (TNG: "The Wounded")
In 2369, Lieutenant Commander Worf informed Commander William T. Riker that the long range sensors of the USS Enterprise-D picked up a distress call from a Romulan warbird. Later, Geordi La Forge was unable to find the Enterprise-D, which was not at the rendezvous point. He told Captain Picard that the long range sensors were at maximum and there was no sign of the Enterprise-D. (TNG: "Timescape")
In 2370, Sam Lavelle performed a long range scan to find the escape pod near the Cardassian border, but without any result. Data suggested it was possible that at this distance, the sensors of the USS Enterprise-D were unable to distinguish the pod from the inorganic matter normally present in space. (TNG: "Lower Decks")
In an alternate timeline, Data, on board the USS Pasteur, performed a long range sensor scan to locate anomalies in the Devron system but found nothing. (TNG: "All Good Things...")
In 2372, Worf performed a long range sensor scan from a console on the bridge of the USS Defiant, searching for Klingon starships. (DS9: "The Way of the Warrior")