page_title: Ralph (New Horizons)
section_title: Specifications
hierarchical_section_title: Ralph (New Horizons) / Specifications
caption_attribution_description: English: This beautiful image obtained with the Ralph/Multispectral Visible Imaging Camera aboard NASA's New Horizons spacecraft shows the night side of Pluto's large, Texas-sized moon Charon, against a star field, lit by faint, reflected light from Pluto itself. The bright crescent on Charon's right side is a sliver of sunlit terrain; it is overexposed. New Horizons was already about 100,000 miles (150,000 kilometers) beyond Pluto when the image was taken on July 15, 2015. The Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, designed, built, and operates the New Horizons spacecraft, and manages the mission for NASA's Science Mission Directorate. The Southwest Research Institute, based in San Antonio, leads the science team, payload operations and encounter science planning. New Horizons is part of the New Frontiers Program managed by NASA's Marshall Space Flight Center in Huntsville, Alabama.
context_page_description: Ralph is a science instrument aboard the unmanned New Horizons spacecraft, which was launched in 2006. Ralph is a visible and infrared imager and spectrometer to provide maps of relevant astronomical targets based on data from that hardware. Ralph has two major subinstruments, LEISA and MVIC. MVIC stands for Multispectral Visible Imaging Camera and is a color imaging device, while LEISA originally stood for Linear Etalon Imaging Spectral Array and is an infrared imaging spectrometer for spaceflight. LEISA observes 250 discrete wavelengths of infrared light from 1.25 to 2.5 micrometers. MVIC is a pushbroom scanner type of design with seven channels, including red, blue, near-infrared, and methane.
context_section_description: Specs:
  Mass— 10.5 kg (23.1 pounds)
  Max power use— 7.1 watts
  Telescope design
  unobscurred
  off-axis
  three-mirror anastigmat
  Aperture 75 mm 
  f/8.7
  Effective focal length 658 mm
  Electronic control boards
  Detector electronics  (DE)
  Command and data handling  (C&DH)
  Low voltage power supply  (LVPS).
  The one telescope feeds light to both LEISA and MVIC channels, with light split by a dichroic beamsplitter.
  MVIC detects light between 400 and 975 nm wavelengths
  LEISA detects light between 1250 and 2500 nm (1.25 to 2.5 μm wavelengths)
  MVIC has seven CCD's that are wide but narrow, utilizing a time-delay integration method to scan over an imaging area. These channels have a resolution of 5024x32 pixels, with the larger direction providing the swath of the image. There are seven channels, with 6 used for time delay integration imaging and the seventh with an array of 5024x128 for navigation framing. MVIC has a field of view that is 5.8 degrees wide The framing channel with 5024x128 pixel size, is panchromatic and a field of view of 5.7 degrees x 0.15 degrees. Unlike the other six channels, it can stare at one target and take an image. The purpose of this channel is to support optical navigation. The Navigation channel is a Frame array that operates as a single frame, rather than the other channels which generate an image by time delay integration.
  MVIC Bands: There are six channels that use Time Delay Integration and another that takes a frame and is for navigation.
  2 panchromatic channels (observing light wavelengths from 400 to 975 nm)
  Blue (400-550 nm)
  Red (540-700 nm)
  Near infrared (from 780 up to 975 nm light wavelengths)
  methane band (860-910 nm)
  Navigation channel / framing array
  LESIA achieved its highest resolution data of Pluto of about 3 km/pixel at New Horizon's closest approach to Pluto on July 14, 2015, when it was 47,000 km distant.
caption: This extremely low-light image is a view of the dark side of Pluto's moon, lit by starlight and Plutoshine. Ralph-MVIC channel data
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