NEAR Earth Swing-By prediction program for DOS

Mike McCants (mikem@fc.net)
Sun, 11 Jan 1998 22:12:14 -0600 (CST) 

I have used a numerical integration program with the vector
given on the NEAR web page and determined Earth-centered
X,Y,Z values for the time period Jan. 23, 06:00UT until 06:48UT.
The file is 97 lines for the 48 minutes with a 30 second interval.
The height and X,Y,Z values are in kilometers.

    Date       Height      X          Y          Z
  23.250000    37654.   9288.102  34796.496  25320.444
  23.250347    37419.   9252.252  34574.479  25231.022
    ...
  23.283333    14594.   5541.363  12495.514  15888.950

I have modified my version of Paul Hirose's program SeeSat version 4
to use this table to generate predictions for any time during this
range.

The input takes the form:

lat 30.315 lon -97.866 height .16

The command "epoch 98023.25" is required.

To generate predictions, enter:

start 1998 jan 23 0620 stop 1998 jan 23 0640 step 0:30

This generates 41 predictions with a 30 second interval.

The output looks like this:

 time   alt azi    R.A.    dec  range   hgt sun
0630:00  39 300   3 55.5  40.59 15758 14526  38
0635:00  36 302   3 43.0  42.06 14368 13019  38
0640:00  32 305   3 27.1  43.72 12989 11504  38

The RA and dec are precessed to 2000 coordinates.
The range and height are in miles.
The "sun" value is the angle between the sun and the Earth limb.

I have compiled this program for DOS and placed it in my ftp area
with the name "jan23.zip".  The zip file contains a batch file
"run.bat" which says "jan23 <inp >out".  The file "inp" should
be modified to contain the lat, long and the time span that you
need predictions for.  Then the "run" command produces output
in the file "out".

If you get "too many users" when you try to ftp, there is a "direct"
link on my "direct.html" web page.

Craig Cholar posted:

>posting here in case there is anyone else in the Washington D.C. metro
>area interested.
>
>                          Alt  Az     RA      Dec        Range
>1/23 06:30 UT (01:30 EST) 26   298  03h 55m  36:32  26557km 16533sm

I have run my program with the Washington, DC, lat, long:
lat 38.8975 lon -77.0092 height .16

 time   alt azi    R.A.    dec  range   hgt sun
0630:00  26 297   3 55.2  36.52 16412 14528  38

This seems to be in good agreement with Craig's prediction.

Mike McCants
mikem@fc.net
http://www.fc.net/~mikem/direct.html  and get jan23.zip
ftp://ftp.fc.net/pub/users/mikem/     and get jan23.zip