1.5.1 Description of Experimental Methods
The NITEOWL experiment is going to measure ozone concentrations using stellar occultation. The decent 
of the rocket through the atmosphere and its rotation allow various stars to be viewed.  Because the 
methods applied do not depend on tracking any particular star, or on the position of the sun or moon,  
measurements may be at any local time during the night.  The data from the ISP is aquired at a rate of one 
frame per second. In each frame several stars will be visible, however the SNR required to do accurate 
inversion will only be achieved by stars of magnitude x or brighter. Each star provides a line of sight 
through the atmosphere. The combination of all the lines of sight seen as the rocket falls is necessary to 
perform tomographic analysis.

The initial measurement of each star will be used as a benchmark for all subsequent measurements of that 
star.  This allows self-calibration of the ISP.  Using the ratio of the initial intensity, which will be the least 
attenuated signal from a given star, and the intensity measured viewing the same star along a different 
line of sight with greater absorption the ozone column amount may be calculated.  Using the column 
amounts one can use a simple onion peeling technique to determine the vertical ozone profile.  The 
expected resolution of such a vertical profile is 1 km.  This resolution is determined by the number of stars 
which provide information pertaining to a each altitude.  Tomographic methods will be employed to 
improve the ozone profile by providing a horizontal component to the result. The expected resolution of 
such a profile is 1 km vertically, and 100 km geographically.  This resolution is based on the number of 
lines of sight through a given volume.