Space and Solar Definitions - C
C-band - A range of microwave radio frequencies in the neighborhood of 4 to 8 GHz.
Caltech - The California Institute of Technology.
Carrier - The main frequency of a radio signal generated by a transmitter prior to application of any modulation.
Carrington Longitude - A system of fixed longitudes rotating with the sun.
Cassegrain - Reflecting scheme in antennas and telescopes having a primary and a secondary reflecting surface to "fold" the EMF back to a focus near the primary reflector.
CCD - Charge Coupled Device, a solid-state imaging detector.
CCS - Computer Command subsystem on board a spacecraft, similar to CDS.
CCSDS - Consultative Committee for Space Data Systems, developer of standards for spacecraft uplink and downlink, including packets.
CDR - GCF central data recorder.
CDS - Command and Data Subsystem onboard a spacecraft.
CDSCC - DSN's Canberra Deep Space Communications Complex in Australia.
CDU - Command Detector Unit onboard a spacecraft.
Centimeter - 10-2 meter.
Centimeter Burst - A solar radio burst in the centimeter wavelength range.
Central Meridian Passage (Cmp) - The passage of an active region or other feature across the longitude meridian that passes through the apparent center of the solar disk.
Centrifugal force - The outward-tending apparent force of a body revolving around another body.
Centripetal acceleration - The inward acceleration of a body revolving around another body.
CGPM - General Conference of Weights and Measures, Sevres France. The abbreviation is from the French. CGPM is the source for the multiplier names (kilo-, mega-, giga-, etc.) listed in this document.
Channel - In telemetry, one particular measurement to which changing values may be assigned.
Chromospheres - The layer of the solar atmosphere above the photosphere and beneath the transition region and the corona.
Chromospheres Events - Some flares are just chromospheres events without centimetric bursts or ionospheric effects. (sid) (class c flare
CIT - California Institute of Technology, Caltech.
CMC - Complex Monitor and Control, a subsystem at DSCCs.
CMD - DSN Command System. Also, Command data.
CNES - Centre National d'Études Spatiales, France.
Coherent - Two-way communications mode wherein the spacecraft generates its downlink frequency based upon the frequency of the uplink it receives.
Coma - The cloud of diffuse material surrounding the nucleus of a comet.
Comets - Small bodies composed of ice and rock in various orbits about the sun.
Comprehensive Flare Index (Cfi) - The indicative of solar flare importance given by the sum of the following five components a) importance of ionizing radiation as indicated by time- associated short wave fade or sudden ionospheric disturbance; (scale 0-3) b) importance of h-alpha flare; (scale 0-3) c) magnitude of 10cm flux; (characteristic of log of flux in units of 10**-22watt/m**2/hz) d) dynamic spectrum; (type ii = 1, continuum = 2, type iv with duration > 10 minutes = 3) e) magnitude of 200mhz flux; (characteristic of log of flux in units of 10**-22watt/m**2/hz)
Conjugate Points - Two points on the earth's surface, at opposite ends of a geomagnetic field line.
Continuum Storm (Ctm) - General term for solar noise lasting for hours and sometimes days.
Coordinated Universal Time (Utc) - By international agreement, the local time at the prime meridian, which passes through Greenwich, England. Therefore, it is also known as Greenwich mean time, or sometimes simply universal time.
Corona - The outermost layer of the solar atmosphere, characterized by low densities (<1.0e+09/cc) and high temperatures (>1,0e+06deg.k).
Coronal Hole - An extended region of the corona, exceptionally low in density and associated with unipolar photospheric regions.
Coronal Rain (Crn) - Material condensing in the corona and appearing to rain down into the chromospheres as observed in h-alpha at the solar limb above strong sunspots.
Coronal Transients - A general term for short-time-scale changes in the corona, but principally used to describe outward-moving plasma clouds.
Cosmic Ray - An extremely energetic (relativistic) charged particle.
CRAF - Comet Rendezvous / Asteroid Flyby mission, cancelled.
Crochet - A sudden deviation in the sunlit geomagnetic field (h component; see geomagnetic elements) associated with large solar flare x-ray emission.
CRS - Cosmic Ray Subsystem, high-energy particle instrument on Voyager.
CRT - Cathode ray tube video display device.
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