==================================================================================

   Description of Commands

In order to measure the actual pointing of the S/C using the FSS and the PMT,
only point 5 (and optionally point 4) is needed.

==================================================================================

1. To remove unnecessary data from the data stream,
switch off SAS data once the Sun is not in the SAS FOV
anymore.

a) stop ADP
b) save Day table
c) copy night table to day EEPROM place
d) run ADP

==================================================================================

2. Calibrate FSS with SAS using VC0 data

read FSS data (VC0)
o=hsi_packet()
o->set,filename='/disks/sunny/raid2/vc0_input_file/<VC0 file>', file_type='smex'
hsi_as_crab_fss, ftime, ft0, fxysc, packet_obj=o, sun=sun
a=hsi_aspect_solution()
a->set,obs_time_interval=hsi_sctime2any(ft0)+minmax(ftime)+[0.2,-0.2]
d=a->getdata(/sas_only,/ras_only, $
  this_ut_ref=hsi_sctime2any(ft0), $
  this_time  =ftime, $
  this_unit_time=2L^20 )
  
fit_fss_sas, [[d.dx],[d.dy]], fxysc, a, ft0, ftime

==================================================================================

3. FSS-VC0 vs FSS-VC1

time offset between VC1 and VC0 data = 1./8 seconds


==================================================================================

4. Create Input Data for the Analysis Program

(This step is needed only if a pointing offset and a blipmin number needs to be
given to the PMT analysis program.)

a)

Edit 'input_i.pro', update t0, offset for PMT, blipmin for PMT
   t0  : Start time of analysis.
   off : Array of pointing offsets [degrees] from the Sun for every data chunk.
   blip: Array of blipmin (input to PMT) for every data chunk (not needed anymore).
         (only even numbers, odd numbers used to input period_est)

b)

input_i, t0, off, blip        ; set t0, array of offsets and blipmin

==================================================================================

5. Plot Pointing

a) 

Set the following variables in the IDL working session.

t0 = anytim('2004-06-08 22:30:00')
!X.style=1
!Y.style=1
window,/free,xsize=400,ysize=400
number=10                         ; number of data chunks to be analyzed
skip  =0                          ; number of data chunks to be skipped
incr  =10000.                     ; length of data chunk in seconds
xrange=[-6.5,0.5]                 ; xrange for plot
yrange=[-2.5,0.5]                 ; yrange for plot
aim_p =[[-5.7288  ,-0.9260], $
        [-5.6610  ,-0.9318], $
        [-5.5938  ,-0.9375], $
        [-5.5266  ,-0.9432], $
        [-5.4621  ,-0.9487]]
                                  ; aiming points (relative to Sun center)
target=[ 83.7002  ,22.0172]       ; aiming point in absolute coordinates (R.A./Dec)
abs_coord=0                       ; =0 relative coordinates, =1 absolute coord
ps=0                              ; =0 plot to current window, =1 make ps-file
print=0                           ; =0 nothing, =1 copy ps-file to lp spooler
zbuffer=0                         ; =0 nothing, =1 write to zbuffer

b)

Execute the following IDL commandline. To change the output device or plotting
properties, the parameters shown in the paragraph above (5a) can be changed.
Note: PRINT=1 works only on UNIX systems using the lp-spooler.

plot_fss_day, t0, number, increment=incr, skip=skip, aim_p=aim_p, target=target, $
              sc_sun_offset=off, blip=blip, /no_range_test, $
              xrange=xrange,yrange=yrange, $
              /out, xout=xout, yout=yout, tout=tout, t0out=t0out, $
              abs_coord=abs_coord, /polar,/oplot,/smooth, $
              ctindex=ctindex, $
              ps=ps, print=print, zbuffer=zbuffer

c)

Optionally 'oplot' some additional info.

==================================================================================

6. Note for R.A. and Dec Plots (needs update)

R.A. and Dec

utplot,tout[iii],era-xout[iii]/cos(edec*!dtor),t0,psym=-4, $
       yrange=[46.47,46.5],ytitle='R.A.'
utplot,tout[iii],edec+yout[iii],t0,psym=-4, $
       yrange=[16.82,16.85], ytitle='Dec'

==================================================================================

7. Before coming to go back to the Sun, re-enable the SAS data.

a) stop ADP
b) copy saved day table to the day EEPROM place.
c) if at night: load night table from EEPROM
d) run ADP

==================================================================================