                 G N O M P L O T    version  4.2


is an ASTRONOMY program for the Atari ST and it is SHARE WARE.

It is not allowed to sell this program or the star charts plotted 
by GNOMPLOT 4.2 without the explicit permission of the author !


You can order your own copy or updates of GNOMPLOT directly  from 

                         Dieter Heinlein
                         Puschendorfer Str. 1
                         D  8501  VEITSBRONN
                         West Germany
                         09 11 / 75 14 76


Please  report any problems,  comments or suggestions  concerning 
GNOMPLOT to the above address.   
If you like this program enough to use it on a regular  basis,  I 
would  be pleased if you could appreciate my efforts  by  sending 
along a few bucks. 
This  will put your name on my list of registered users and  will 
enable me to inform you on new releases or any major bugs fixed.


Hardware  requirements:   Atari ST with 1 Mbyte  RAM,  monochrome 
monitor (Hi-Res only) and Epson FX80- compatible matrix printer.

The  following files should be in the same directory (desktop  or 
folder)
               GNOMPL42.PRG          main prg, incl. star data
               GNOMPLOT.RSC                resource file
               HARDCOPY.PRG              auxiliary program
               GNOMPLOT.TXT                 this manual


GNOMPLOT was designed in order to calculate and to print out star 
charts using the gnomonic projection.

Such maps show a small region of the starry sky (around the  pro-
jection  center)  and make it possible to  draw  trajectories  of 
METEORS as straight lines !


Make  sure  that at least the four files described above  are  on 
your  working  directory and that you have  enough  free  memory. 
Otherwise remove Accessories or/and too large RAM-Disk.

Then start the program by double-click on the GNOMPL42.PRG icon.

The drop down menu of GNOMPLOT V4.2 is self-explanatory.  Only  a 
few comments on some program features may be still useful:

It  is possible to switch the pull down menu OFF / ON by pressing 
the <ESC> key. [ This won't work while using special functions !]
MENU Desk:

About GNOMPLOT:
     will show a copyright message.

Desk Accessories:
     It  is possible to run Accessories from the  GNOMPLOT  desk, 
     but you should be aware,  that (in actual release) the back-
     ground, that was covered by the ACC, will NOT be restored.

     
MENU Gnomonic chart:

Set parameters:
     You will be prompted to input the equatorial coordinates for 
     the center of gnomonic projection:
          right ascension (hours):        0.0 ......  23.99
          declination (degrees):        -90.0 ...... +90.0
          scale factor of screen:  150 (overview) ... 450(detail)     
     Default value for center of screen is the position  320/200. 
     If you want to change this value: type <y>, otherwise <CR>.
      
Read star data / Change limiting magnitude:
     GNOMPLOT contains data of right ascension,  declination  and 
     apparent magnitude for 5033 stars up to mag +6. These values 
     are read in ascending order of magnitude.  You can stop data 
     input by pressing <ESC> if the desired magnitude is reached. 
     [ Notify that the standard equinox for RA and DE is J 2000 ]

Erase screen:
     This option will clear screen, but does NOT erase the chosen 
     parameters  of  the actual projection in  memory.  Use  this 
     function to draw a coordinate grid WITHOUT stars.

Quit or Ctrl-C:
     Quit will exit GNOMPLOT with query. ^C exits to desktop fast


MENU Functions:

Insert / remove main axes:
     The main axes of the screen center are shown / erased.

Coordinate grid:
     Distance of grid lines: 1 hour in RA and 10 degrees in DE !!

Locate coordinates: 
     This locate mode shows RA/DE values of the current  position 
     of mouse icon. Cancel function with right mouse button.
     
Show constellation:
     Invoking this function first time will cause sorting of  all 
     star data according to constellations. After that just klick 
     left (exactly) on any (major) star and all stars that belong
     to  the same constellation and its latin name are shown  up. 
     Press <ESC> to cancel blinking.  Clicking right button exits 
     the searching mode and returns to main menu.
Draw trajectories:
     To  draw a meteor path (trajectory) mark the  initial  point 
     with the left and choose the final point with right  button. 
     Press <ESC> to cancel the drawing mode.


MENU Pictures:

Degas / Doodle:
     Toggles the picture format (active format is checked). 

Load Pic:
     Load Degas / Doodle Picture from working directory.

Save Pic:
     A message about the space available on the actual drive will 
     appear  and  enables  you to save a picture  of  the  chosen 
     format on the current working directory.

Kill Pic:
     will erase pictures of any format from working directory.


MENU Hardcopy:

Normal:
     enables 'correct scale' output of entire screen to printer.
     ( 640x400 pixels / for Epson FX80 / format: 225x140 mm )

Partial:
     Using the drag_box you can choose the location of an 384x240 
     pixel wide area on the screen.  Fix its position by clicking 
     the left mouse button and you will receive a printer  output 
     of this area, that is  expanded twice in  length and height. 
     ( format: 270x169 mm )
     
Special:
     BEFORE  using this function it is necessary to save the  de-
     sired  screen as a DOODLE Picture !  After that invoke  item 
     'Special' and choose this picture from the file select  box. 
     Then a correct scale and FULL DIN A4 SIZED hardcopy of  this 
     PIC  will be sent to your printer ( format: 259x162 mm )  
     

All  functions that occur in the pull down menu are  implemented. 
Some  items are SHADOWED (disabled) temporarily to indicate  that 
these functions can't be activated at present. In order to enable 
them you must calculate a new set of projection parameters first.  


Relation of star magnitude and radius of dot on the screen:

  mag:     -1.5 ..... 0 ..... +1.5 ..... +3 ..... +4.5 ..... +6
r(pixels):        4       3          2        1          0 


Veitsbronn,  March 18, 1988                   Dieter Heinlein
