This classification was developed from broad band spectra ( between 0.31 μm and 1.06 μm ) obtained during the Eight-Color Asteroid Survey ( ECAS ) in the 1980s , in combination with albedo measurements .
This classification was developed from broad band spectra ( between 0.31 μm and 1.06 μm ) obtained during the Eight-Color Asteroid Survey ( ECAS ) in the 1980s , in combination with albedo measurements ( 4 ) .