Clementine 5 Band UVVIS Spectra:

     Five band spectra from calibrated Clementine images taken at 415, 750, 900, 950 and 1000 nm can easily be created by downloading the images in 16 bit tiff format from the USGS map-a-planet website (pdsmaps.wr.usgs.gov/PDS/public/explorer/html/moonpick.htm ).  It is extremely important to use the 16 bit tiff images and not the jpg images because the latter are suitable only for mapping purposes.

     Downloaded images are then opened in the freeware program ImageJ (see rsb.info.nih.gov/ij/). Select the Image menu, the Stacks submenu, and the Convert Images to Stacks option. The images will appear as an image stack and you can move between then using the arrow keys on the image display. Simply draw a box around the area that you want to obtain five band spectra from.  Next, from the Analyze menu select Histogram (or you can simply type Control H). Enter No when asked if a 5 band display is wanted. The greyscale average for the pixel box and the number of pixels in the box is displayed.  Repeat the process for each image in the image stack, recording the greyscale average for each image. Multiply the greyscale value by 0.000135 for each wavelength (this converts the value to absolute reflectance).

     Next, in your favorite spreadsheet program (I prefer Excel) make two columns: one for the wavelength and the second for the average greyscale value of the boxed area multiplied by 0.000135.  Plot the wavelength on the x axis and the absolute reflectance on the y axis of a chart.  This is the five band spectra for the boxed area.  The spectra can be interpreted for mineral content by referring to this paper by Tompkins and Pieters (Composition of the Lunar Crust beneath the Megaregolith, Lunar and Planetary Science XXVIII abstract number 1251).

     A sample calculation for Dionysius is shown below:

     The method used to calibrate the USGS 16 bit tiff images is outlined by Pieters [see Pieters CM (1999) The moon as a spectral calibration standard enabled by lunar samples: The Clementine example. Workshop on new views of the moon2: Understanding the moon through the integration of diverse datasets. Flagstaff, Az. abstract #8025].  

     Analysis of mineral content by the specific shape characteristics of the 5 band UVVIS spectra in a reflectance vs wavelength plot has been described by Tompkins and is discussed here:  Tompkins, S. (1998) Mafic Plutons in the Lunar Highland Crust. LPSC XXIX p.999-1000.  It is also discussed in Tompkins, S. and Pieters CM (1999) Minerology of the Lunar Crust: Results from Clementine. Meteoritics & Planetary Science, 34, p. 25-41. Additional description of this method is given in issue #11 of the free online journal Selenology Today (see side menu).