Instrument Functional Description: The VIS Instrument is a Set of three Low Light Level Cameras. Two of these Cameras share primary and some secondary Optics and are designed to provide Images of the Nighttime Auroral Oval at Visible Wavelengths. A Third Camera is used to monitor the Directions of the Fields-of-View of the Auroral Cameras with respect to the sunlit Earth and return Global Images of the Auroral Oval at Ultraviolet Wavelengths. The VIS Instrumentation produces an Auroral Image of 256 × 256 Pixels approximately every 24 s dependent on the Integration Time and Filter selected. The Fields-of-View of the two Nighttime Auroral Cameras are 5.6 × 6.3° and 2.8 × 3.3° for the Low and Medium Resolution Cameras, respectively. The Medium Resolution Camera was never activated. One or more Earth Camera Images of 256 × 256 Pixels are produced every 5 min, depending on the commanded Mode. The Field-of-View of the Earth Camera is approximately 20 × 20°. See: http://vis.physics.uiowa.edu/vis/vis_description/vis_description.htmlx Reference: Frank, L.A., J.B. Sigwarth, J.D. Craven, J.P. Cravens, J.S. Dolan, M.R. Dvorsky, J.D. Harvey, P.K. Hardebeck, and D. Muller, The Visible Imaging System (VIS) for the Polar Spacecraft, Space Science Review, Vol. 71, pp. 297-328, 1995. Data Set Description: The VIS Earth Camera Data Set comprises all Earth Camera Images for the selected Time Period. Full Coordinate Information is included for Viewer Orientation. In addition, a Rotation Matrix and a Table of Distortion-correcting Look Direction Unit Vectors are provided for the Purpose of calculating Coordinates for every Pixel. To facilitate viewing of the Images, a Mapping of Pixel Value to a recommended Color Table based on the Characteristics of the selected Filter will be included with each Image. A Relative Intensity Scale is provided through an Uncompressed Count Table. Approximate Intensity Levels in kiloRayleighs are given in an Intensity Table. For detailed Information on Intensities, see Sensitivities_and_Intensities.txt at https://cdaweb.gsfc.nasa.gov/Polar_VIS_docs/SENSITIVITIES_AND_INTENSITIES.TXT. Supporting Software is available at: http://vis.physics.uiowa.edu/vis/software/ Included is an IDL Program that displays the Images with the recommended Color Bar, provides approximate Intensities, Coordinate Data for each Pixel, and includes multiple Options for Image Manipulation.

The Extreme Ultraviolet Imager (EUVI) is part of the Sun Earth Connection Coronal and Heliospheric Investigations (SECCHI) instrument suite on the NASA STEREO mission. The SECCHI on the two STEREO spacecraft are identical suites of remote sensing instruments designed to observe coronal mass ejections (CMEs) at the Sun and in transit outwards to 1 AU.EUVI measured emission lines at 30.4 nm (He II), 17.1 nm (Fe IX), 19.5 nm (Fe XII), and 21.1 nm (Fe XIV). The EUVI's 2048 x 2048 pixel detectors have a field of view out to 1.7 solar radii, and observe in four spectral channels that span the 0.1 to 20 MK temperature range. In addition to its view from two vantage points, the EUVI will provide a substantial improvement in image resolution and image cadence over its predecessor SOHO-EIT, while complying with the more restricted mass, power, and volume allocations on the STEREO mission.

Instrument Functional Description: The VIS Instrument is a Set of three Low Light Level Cameras. Two of these Cameras share primary and some secondary Optics and are designed to provide Images of the Nighttime Auroral Oval at Visible Wavelengths. A Third Camera is used to monitor the Directions of the Fields-of-View of the Auroral Cameras with respect to the sunlit Earth and return Global Images of the Auroral Oval at Ultraviolet Wavelengths. The VIS Instrumentation produces an Auroral Image of 256 × 256 Pixels approximately every 24 s dependent on the Integration Time and Filter selected. The Fields-of-View of the two Nighttime Auroral Cameras are 5.6 × 6.3° and 2.8 × 3.3° for the Low and Medium Resolution Cameras, respectively. The Medium Resolution Camera was never activated. One or more Earth Camera Images of 256 × 256 Pixels are produced every 5 min, depending on the commanded Mode. The Field-of-View of the Earth Camera is approximately 20 × 20°. See: http://vis.physics.uiowa.edu/vis/vis_description/vis_description.htmlx Reference: Frank, L.A., J.B. Sigwarth, J.D. Craven, J.P. Cravens, J.S. Dolan, M.R. Dvorsky, J.D. Harvey, P.K. Hardebeck, and D. Muller, The Visible Imaging System (VIS) for the Polar Spacecraft, Space Science Review, Vol. 71, pp. 297-328, 1995. Data Set Description: The VIS Earth Camera Data Set comprises all Earth Camera Images for the selected Time Period. Full Coordinate Information is included for Viewer Orientation. In addition, a Rotation Matrix and a Table of Distortion-correcting Look Direction Unit Vectors are provided for the Purpose of calculating Coordinates for every Pixel. To facilitate viewing of the Images, a Mapping of Pixel Value to a recommended Color Table based on the Characteristics of the selected Filter will be included with each Image. A Relative Intensity Scale is provided through an Uncompressed Count Table. Approximate Intensity Levels in kiloRayleighs are given in an Intensity Table. For detailed Information on Intensities, see Sensitivities_and_Intensities.txt at https://cdaweb.gsfc.nasa.gov/Polar_VIS_docs/SENSITIVITIES_AND_INTENSITIES.TXT. Supporting Software is available at: http://vis.physics.uiowa.edu/vis/software/ Included is an IDL Program that displays the Images with the recommended Color Bar, provides approximate Intensities, Coordinate Data for each Pixel, and includes multiple Options for Image Manipulation.