Broad Design of Experiment
	The NITEOWL experiment is to be launched from Churchill, MB aboard a "Orion" rocket. This rocket will take the experiment to an altitude of 80km.  From apogee the experiment will fall to earth beneath a parachute specially designed to provide a known, low rate of spin.  As the payload falls measurements allowing the calculation of the abundance of ozone will be taken using an optical spectrograph.  The position of the rocket and instrument will be monitored using a (GPS) Global Positioning System.  This will be used both to track the altitude and geographic position of the instrument during flight and to facilitate post-flight recovery.  An attitude video camera (AVC) will be included in the payload to monitor the direction from which the ISP is recieving its input signal.  There will be two data streams sent from the NITEOWL experiment to receiving equipment on the ground.  The first data stream will include the measurements made by the ISP and the GPS.  The second will transmit the information generated by the AVC.  A block diagram of the entire instrument is shown in Figure 1-1.


Figure 1-1 Block Diagram of the NITEOWL Experiment
	The ISP will measure the intensity of incident starlight after it has been attenuated by the atmosphere and dispersed using a diffraction grating.  The dispersed and attenuated light will be focused on a CCD (Charge Coupled Device) detector.  The spectral resolution of the data collected by the CCD will be 5 nm with a total wavelength range of 400 nm ranging over the Chappuis band from 400 to 800 nm.  The CCD detector readout will be sent to the on-board data compression system which will take incoming data from both the GPS and the detector and pass all of the information to the telemetry system which will transmit the data to a receiving system on the ground.
	The attitude video camera is an optical camera which has a wider field of view than the optical system and is used to determine the pointing direction of the optical system.  This camera transmits the images it receives down to the data processing equipment on the ground on a separate frequency.
	The first section below describes the methods which will be used to aquire and analyse the optical data.  The instrumentation used is described in more detail in section 1.5.2.  Section 1.5.3 describes the resolution and confidence which are expected to be obtained for the ozone concentration profile.  Last the zeroth level data processing and ground-based validation which will be discussed.
Description of Experimental Methods

Instruments
	The starlight from a field of view which subtends 15 degrees horizontally and 7.5 degrees vertically will be imaged by the optical system on the CCD detector.  This starlight is assumed to be emitted by point sources and to arrive at the entrance to the optical system collimated.  The first element in the optical system is a transmission grating which diperses the collimated light which is incident from the stars in the field of view.  This dispersed light is then focused on the CCD detector by an objective lens.  These two elements have been chosen such that the dispersion of the incoming light by the transmission grating allows the objective lens to project an image onto the CCD detector such that 5 nm of the spectrum covers a single pixel of the CCD detector.
	The global positioning system is to be provided by Bristol aerospace as an integrated portion of the orion rocket telemetry system.  This system should allow tracking of the experiment with a precision of up to 100 m.
	The attitude video camera will be a camera with a CCD detector with a wide enough field of view and a high enough sensitivity that one can be assured of enough stars being in the field of view at all times to be able to determine the pointing direction of the optical system.  This type of system has been used on both Gemini and oedipus-c missions.
Expected Performance