Landsat Surface Reflectance CDRs are generated using Landsat Ecosystem Disturbance Adaptive Processing System (LEDAPS) software, which applies Moderate Resolution Imaging Spectroradiometer (MODIS) atmospheric correction routines to Landsat Level-1 scenes.
The following products are available as options when requests for surface reflectance processing are made through the on-demand USGS Earth Resources Observation and Science (EROS) Center Science Processing Architecture (ESPA) system (https://espa.cr.usgs.gov/):
● Source Products (Landsat Level-1 Product or Metadata, or both)
● Top-of-Atmosphere Reflectance [Hierarchical Data Format for Earth Observing System (HDF-EOS) data format]
● Surface Reflectance (SR) (HDF-EOS data format)
● Band 6 Brightness Temperature (HDF-EOS data format)
+ Landsat Surface Reflectance Climate Data Records Fact Sheet [PDF]
+ Landsat Surface Reflectance Climate Data Records

STELLA: A DIY Handheld Scientific Instrument
If you are looking for a do-it-yourself (DIY) handheld spectrometer, you need to meet STELLA. STELLA (Science and Technology Education for Land/Life Assessment) is a portable scientific instrument developed by