@prefix skos: . @prefix ns0: . skos:prefLabel "Cameras"@en ; a skos:Concept ; skos:narrower . skos:changeNote """2015-05-12 13:14:28.0 [saritz] Changed Nimbus to mixed case. update AltLabel (Automatic Picture Transmission System on Nimbus-1); update PrefLabel (APT Nimbus-1); """ ; ns0:altLabel [ ] ; skos:definition """[Source: National Space Science Data Center, http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1964-052A-02 ] The Nimbus 1 Automatic Picture Transmission (APT) system was a camera and transmitter combination designed to transmit local daytime, slow-scan television pictures of cloudcover conditions to properly equipped ground receiving stations on a real-time basis. The camera used a 108-deg wide-angle f/1.8 objective lens with a focal length of 5.7 mm. The camera was mounted facing earthward on the H-frame inside the sensory ring, with its optical axis parallel to the spacecraft spin axis. The actual picture taking required 8 s and the transmission 200 s. Earth-cloud images retained on the photo-sensitive surface of the 2.54-cm-diameter vidicon were read out at four lines per second to produce an 800-line picture. A 5-W TV transmitter (136.95 MHz) relayed the pictures to local APT stations within communication range. The faceplate of the vidicon had reticle marks that appeared on the picture format to aid in relating the picture to its geographical position on the earth's surface. At the nominal satellite altitude, a picture covered approximately a 1660- by 1660-km square with a horizontal resolution of around 3 km at nadir. The experiment supplied over 1600 high-quality cloudcover pictures to participating APT stations during the spacecraft's 3.5-week lifetime. It proved the capability of weather satellites to provide high-quality daytime local cloudcover data to operational meteorologists on an essentially real-time basis. Its success bolstered the decision to include such instrumentation in the TIROS Operational System (TOS). For more detailed information of the experiment, see "APT Users' Guide" (TRF B04499), available from NSSDC. APT data are primarily intended for operational use within the local APT acquisition station and are generally not available for distribution. Group: Instrument_Details Entry_ID: APT NIMBUS-1 Group: Instrument_Identification Instrument_Category: Earth Remote Sensing Instruments Instrument_Class: Passive Remote Sensing Instrument_Type: Photon/Optical Detectors Instrument_Subtype: Cameras Short_Name: APT NIMBUS-1 Long_Name: Automatic Picture Transmission System on NIMBUS-1 End_Group Group: Associated_Platforms Short_Name: NIMBUS-1 End_Group Group: Spectral_Frequency_Information Wavelength_Keyword: Visible End_Group Online_Resource: http://nssdc.gsfc.nasa.gov/nmc/experimentDisplay.do?id=1964-052A-02 Online_Resource: http://nasascience.nasa.gov/missions/nimbus Online_Resource: http://atmospheres.gsfc.nasa.gov/nimbus/ Creation_Date: 2009-07-16 Group: Instrument_Logistics Instrument_Owner: USA/NASA End_Group End_Group"""@en ; skos:prefLabel "APT Nimbus-1"@en ; skos:inScheme ; skos:broader ; a skos:Concept .