• A Roy Chowdhury

      Articles written in Journal of Earth System Science

    • Terrain mapping camera for Chandrayaan-1

      A S Kiran Kumar A Roy Chowdhury

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      The Terrain Mapping Camera (TMC) on India’s first satellite for lunar exploration, Chandrayaan-1, is for generating high-resolution 3-dimensional maps of the Moon. With this instrument, a complete topographic map of the Moon with 5 m spatial resolution and 10-bit quantization will be available for scientific studies. The TMC will image within the panchromatic spectral band of 0.4 to 0.9 Μm with a stereo view in the fore, nadir and aft directions of the spacecraft movement and have a B/H ratio of 1. The swath coverage will be 20 km. The camera is configured for imaging in the push broom-mode with three linear detectors in the image plane. The camera will have four gain settings to cover the varying illumination conditions of the Moon. Additionally, a provision of imaging with reduced resolution, for improving Signal-to-Noise Ratio (SNR) in polar regions, which have poor illumination conditions throughout, has been made. SNR of better than 100 is expected in the ±60° latitude region for mature mare soil, which is one of the darkest regions on the lunar surface. This paper presents a brief description of the TMC instrument.

    • Hyper-Spectral Imager in visible and near-infrared band for lunar compositional mapping

      A S Kiran Kumar A Roy Chowdhury

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      India’s first lunar mission, Chandrayaan-1, will have a Hyper-Spectral Imager in the visible and near-infrared spectral bands along with other instruments. The instrument will enable mineralogical mapping of the Moon’s crust in a large number of spectral channels. The planned Hyper-Spectral Imager will be the first instrument to map the lunar surface with the capability of resolving the spectral region, 0.4 to 0.92 Μm, in 64 continuous bands with a resolution of better than 15 nm and a spatial resolution of 80 m. Spectral separation will be done using a wedge filter and the image will be mapped onto an area detector. The detector output will be processed in the front-end processor to generate the 64-band data with 12-bit quantization. This paper gives a description of the Hyper-Spectral Imager instrument.

  • Journal of Earth System Science | News

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