There are five example programs at both Fortran and C languages
These programs should be linked against ners library. 
In addition, there are four examples of python wrappers. 

These examples can be compiled with a make file that has the following lines
.c.o:
	gcc -I${NERS_PREFIX}/include -c -o $*.o $*.c

.f.o:
	gfortran -ffree-form -I$(NERS_PREFIX)/include -c -o $*.o $*.f # for gfortran

.f.o:
	ifort -FR -fpp -I$(NERS_PREFIX)/include -c -o $*.o $*.f # for intel ifort compiler

The following line should be added to the command line for linking: -L$(NERS_PREFIX)/lib -lners
Here NERS_PREFIX is the prefix where NERS library is installed.


1) Test program NERS_FORTRAN_EXAMPLE_01 demonstrates how to compute   
   the Earth rotation matrix that transform a vector in the rotating  
   terrestrial coordinate system fixed with respect the Earth's       
   crust to the inertial non-rotating celestial coordinate system.    

2) Test program NERS_FORTRAN_EXAMPLE_02 demonstrates how to compute   
   TAI time that corresponds to UTC time tag. The UTC time tag        
   is expressed as sum of days elapsed since 2000.01.01_00:00:00 UTC  
   epoch multiplied by 86400.0 and the UTC time tag with respect to   
   the midnight.                                                      

3) Test program NERS_FORTRAN_EXAMPLE_03 demonstrates how to compute   
   the time series of 8 Earth orientation parameters with a specified 
   time step for the specified time range and print them as a table.  
   NB: the units in the table are not SI units, but the non-standard  
   units historically used in the past.                               

4) Test program NERS_FORTRAN_EXAMPLE_04 demonstrates how to learn     
   the range of dates for which the NERS provides the Earth           
   orientation parameters. NERS routine NERS_INQ returns either two   
   ranges:  1) the range of the EOP forecast which is based on        
   measurements, also called the data assimilation range and          
   2) the long-term prediction that is based in extrapolation, or     
   the time epoch of the forecast generation. It is assumed that the  
   EOP long-term prediction will be used only in a case of either     
   NERS servers failure or a failure of the NERS client to establish  
   Internet connection.                                               

5) Test program NERS_FORTRAN_EXAMPLE_05 demonstrates how to compute
   elevation angle, azimuth and hour angle at a given moment of time
   for a station with given Cartesian coordinates observing a source
   with given right ascension and declination.

6) Test program NERS_FORTRAN_EXAMPLE_06 demonstrates how to compute
   right ascension and declination, as well its rates of change, 
   at a given moment of time for a station with given Cartesian 
   coordinates observing a source with given azimuth, elevation,
   and time.

Test programs ners_c_example_01.c, ners_c_example_02.c, ners_c_example_03.c, 
ners_c_example_04.c, ners_c_example_05.c, and ners_c_example_06.c are 
analogous to Fortran code.

Python wrappers:

a) ners_python_get_eop_example.py

b) ners_python_utc_to_tai_example.py

c) ners_python_azelha_example.py

d) ners_python_radec_example.py

e) ners_python_transform_example.py
