The Multi-angle Imaging SpectroRadiometer (MISR), aboard NASA's Terra satellite, views the sunlit Earth with cameras pointed at nine widely spaced angles. As the instrument flies overhead, each region of Earth's surface is successively imaged by all of the cameras in each of four wavelengths (blue, green, red, and near-infrared). 

MISR is the first such instrument to be flown in space, and it provides ongoing global coverage with high spatial detail. Its imagery is carefully calibrated to measure the brightness, contrast, and color of reflected sunlight. 

Scientific Applications

MISR provides data for scientists studying Earth's atmosphere and climate, such as:

• The partitioning of energy and carbon between the land surface and the atmosphere

• The regional and global impacts of different types of atmospheric particles and clouds

Unique Capabilities

The change in light reflection at different view angles allows researchers to distinguish different types of:

• Atmospheric particles (aerosols)
• Cloud forms
• Land surface covers

Combined with stereoscopic techniques, this enables construction of 3-D models and estimation of the total amount of sunlight reflected by Earth's diverse environments.

MISR Camera

MISR employs nine discrete cameras pointed at fixed angles, named Df, Cf, Bf, Af, An, Aa, Ba, Ca, and, Da, beginning with the most forward-viewing oblique camera and ending with the most aft-viewing oblique camera. 

The initial letter (A, B, C, D) denotes the focal length of the camera lens, with the A cameras having the shortest focal length and the D cameras the longest. With the exception of the A design, which is used for the nadir view as well as the near-nadir views, each letter (B, C, D) also denoted the camera angle, that is, the zenith angle of the optical axis of the camera. 

The small letters (f, n, a) denote whether the camera is looking forward, nadir, or aftward. Nominally, the view angles for the off-nadir A, B, C, and D cameras are 26.1, 45.6, 60.0, and 70.5 degrees, respectively, relative to a local horizontal plane at mean sea level.