MSI/NIS I - ASIA/MIDDLE EAST:
This is the first section of the earth observations. The spacecraft flies roughly over the north
pole and down across Asia and the Middle East.

POINTING -  At about 23/06:49 we slew the boresight to an inertial position (RA=69.37 , Dec=- 57.68) and HOLD.  
We define the boresight as the best currently known center of the MSI fov. This is the same boresight used at Mathilde, where  
MSI is 15.04 'short' pixels toward +z from x', and 2.99 'long' pixels toward -y from x'.  A 'short' pixel = .000095895
ur, a 'long' pixel = .00016182 ur.  See Scott Murchie's memo from August 15, 1996, "Geometric properties of MSI" based on 
analyses of the may 1996 star cals.  NOTE: This boresight offset used for all Earth observations.

At this position the boresight will fall along the desired ground track across Asia, Middle East, Saudi Arabia, 
etc. during closest approach; it also keeps z-axis 45 deg off sun.  There is no slewing during these sequences. 
Images and NIS spectra are acquired as the boresight passively falls over the surface of the earth. 

MSI:
see plots:  /pre-eros/earthmoon_flyby/msiearth1.gif - shows zoomed out view of whole earth with all 6 sets of 8 images each
                                       aral.gif    -   shows the 8 image set near aral sea
                                      mideast.gif  -  shows iran, persian gulf, saudi1, saudi2 sets
                                      ethiopia. gif  - shows the 8 image set in ethiopia


First we acquire two dark sky images when the boresight has not yet come on the Earth.  Prior to and during closest 
approach, we acquire six sets of 8 monochrome images each while the ground- track passively sweeps across Asia, the 
Middle East, and Africa.  In the first 5 sets, images are acquired 2 seconds apart. In the last set (Ethiopia), 
images are acquired 3 seconds apart.  There is no slewing here.



NIS:

see plots:     /pre_eros/earthmoon_flyby/nisflygrndtrka.gif       northern view of nis footprint groundtrack
                                         nisflygrndtrkb.gif       equatorial view of nis footprint groundtrack
                                                                   (only one frame plotted per minute in these plots)
                                         nisflyoverlap.gif        shows how the overlap changes throughout the observation
                                                                   due to changing rate of territory movement 

- A few minutes before the boresight falls onto the lit portion of the Earth, we execute NIS
Sequence 3 followed immediately by Sequence  4.  We repeat execution of these two sequences
13 additional times.  In Sequence 3, 100 individual spectra are acquired consecutively (one second
per spectrum), with no mirror stepping. There is no delay between spectra. In Sequence 4 NIS
acquires 4 individual dark spectra.  There is no mirror stepping, mirror position 75 is used
throughout. Data acquisition ends a few minutes after the boresight passes off the lit part of the
Earth and into dark sky.