491 Echosounder Operation Manual Brandname: NorthStar Category: Marine Equipment Total Pages: 76 Table of contents Contents2Welcome5WelcometoTheNorthstar4916Conventions7TechnicalSupport8HowEchoSoundingWorks9PoweringThe491OnandOff11UsingThe491With12Figure313Figure6Illustrated16Figure7Illustrated17UsingDemoMode18EchoSounding19UsingAutomaticMode20Manually21Figure822ZoomingInandOut23UsingBottomZoom24UsingBottomLock25LeavingZoomMode26EnteringNumerical27TransducerDepth28Speedand29ThePictureMenu32UnderstandingThe36SettingTheWhite37UnderstandingDepthSettings39ViewingTheSeabedDepth40UsingTheMoreKey46DisplayingTheA-Scope47UsingTheA-Scope48BottomDepthBox49TemperatureGraph50Archivingand51Archivingand52MarkingFishAsWaypoints57GoingDirectlytoA58SettingTheAlarms59UnderstandingTheAlarms60SettingTheAlarmS61SettingInsideOr62SettingTheBottom63TurningTheBottom64SettingTheUpper65TheAlarm66CheckingTheTransducer69MaintainingA70Glossary75