

                            ASTROMETRICA SHAREWARE
                           


 This is an  unclicensed version of  "Astrometrica".  As usual,  you may use
 this shareware two weeks for free. After you have tested this software, you
 either delete all copies,  or register yourself as licensed user. To do so,
 send at least US$ 25.- to the author of  "Astrometrica"  and you will get a
 licensed copy of the latest version of this shareware.

 As a shareware author,  you may use  the program  for free,  but you should
 contact the author of  "Astrometrica", too:  After sending a description of
 your  shareware-programs  to the address  given  below,  you will receive a
 licensed copy of the latest version of "Astrometrica", too.

 The licensed version of  "Astrometrica"  offers  the  following  additional
 functions, disabled in this unlicensed copy:

 * Up to  ten reference stars can be selected,  whereas  an  unlicensed copy
   allows the selection of four stars only.

 * Determination  of the  brightness  of the object  of interest,  using the
   'Measure Position & Mag' command.

 * Comparison of two CCD-images by electronically blinking them.

 * Calculation of ephemeris for the end of evening twilight or the beginning
   of morning twilight, and a "what's up" function.

 The address of the author, where you can order licensed versions of "Astro-
 metrica", is:

                                 Herbert Raab
                                Schrammlstr. 8
                                 A-4050 Traun
                                   Austria


 The following documentation  refers to the full version of  "Astrometrica".
 Some of the functions are therefore  not  available when using a unlicensed
 shareware-version.




                               ASTROMETRICA 2.0
                              


  ABOUT ASTROMETRICA
  

  "Astrometrica"  1.0  was  implemented  between  February and June 1993  in
  order to check the possibility  of using  CCD-cameras for astrometric work
  on minor planets and comets.

  During the developement of "Astrometrica",  in the months mentioned above,
  about  150  CCD images of comets were measured successfully.  Thus, it was
  possible to adapt the program to the needs of practical working amateurs.

  Version 1.1 was created in September 1993.  It allowed  loading compressed
  ST-6 files and writes,  besides the conventional REPORT file, a file named
  CREPORT,  which is compatible to the standard format given on M.P.C. 18847
  to 18849 (October 1991).  This file  may be used  for sending  astrometric
  observations via computer networks or on diskette.

  Version 1.2,  which was released in October 1993, supported the comparison
  of two CCD images by electronically blinking them. The method used to dis-
  playing  CCD images was improved,  and the access to  GSC regions has been
  sped up, too.

  A major step is  Version 2.0,  which was finished in April, 1994:  Besides
  some new small, but nevertheless useful features, like negative display of
  CCD images,  the Scan function for orbital elements to create a "What's up
  tonight" listing,  and  the function for  remeasuring  the object  without
  having to measure the reference stars, again,  it is now possible  to work
  not only with ST-6 images, but also with ST-4 and TIFF images.
  Furthermore,  the methods  for astrometric  and photometric data reduction
  have been improved,  and the ASTROMET.LOG file now gives more detailed in-
  formation on the measurement than REPORT.TXT and CREPORT.TXT.


  WHAT YOU NEED
  

  * PC-compatible computer with 80286 (or later) CPU,  standard VGA graphics
    card, Microsoft-compatible mouse, and 512kB free memory.

  * MS-DOS 5.0 (or later version).

  * The  "Hubble Space Telescope Guide Star Catalog"  (GSC),  version 1.0 or
    1.1,  on CD-ROM  or copied onto the computer's hard disk,  with the same
    directory structure as on the CD-ROM.
    The two GSC CD-ROM's are available from the following adress:

                    Astronomical Society of the Pacific
                    390 Ashton Ave.
                    Dept. AD
                    San Francisco, CA 94112
                    USA


  WHAT'S ON THE DISK
  

  The diskette holds the following files:

  * ASTROMET.EXE: The executeable "Astrometrica"-program.

  * REGIONS.DAT: A file which holds information  on the location of the GSC-
    regions.

  * README.BAT and README.TXT: The text you are reading  and a batch-file to
    display it.

  * LIESMICH.BAT and LIESMICH.TXT: The german version of this text and a the
    batch-file to display it.

  * CCD:  A sundirectory with some sample images and a text file, containing
    some comments to these images.

  * ELM:  A subdirectory  with the orbital elements  of the objects  on  the
    sample images.


  INSTALLING ASTROMETRICA
  

  Installing  "Astrometrica"  on  your  computer's  hard disk drive  is very
  simple.  Using  the  MS-DOS  command  MD  (for  Make Directory),  create a
  directory to operate from and then copy the files from your "Astrometrica"
  floppy disk onto your hard disk.  You may also  copy the sample images and
  the orbital elements to the subdirectories where you store your CCD images
  and orbital elements, respectively.

  When you start  "Astrometrica"  for the first time,  a message will appear
  telling  you  that the  file for  initializing  the  software could not be
  found.  You should go  trough the 'Options'-menue  now  and  configure the
  sofware, as described later.


  COMMANDS
  

  ͻ
   Menue    Command           Description                               
  ͹
   File     Load Image        Load,  depending  on  the  configuration, 
                              ST-6, ST-4 or TIFF-images  from disk into 
                              the main memory.                          
           Ķ
            View Text-File    Load and display a text-file.             
           Ķ
            Change Dir        Change the default directory.             
           Ķ
            DOS Shell         Temporarily exit to DOS.                  
           Ķ
            Exit              Exit "Astrometrica".                      
  Ķ
   Display  Chart             Display a chart of a part of the sky.     
           Ķ
            Image             Display the current image.                
           Ķ
            Parameters        Display information on the current image. 
           Ķ
            Negative          Toggle negative display of the CCD image. 
           Ķ
            Load User         Load and set a ST-6 color table.          
            Color Table                                                 
           Ķ
            Set Standard      Set the standard color table.             
            Color Table       (Gray-scale)                              
  Ķ
   Measure  Select Reference  Display a  chart of that  part of the sky 
            Stars             seen on the CCD image, in order to select 
                              the  reference stars,  which will be used 
                              to calculate the  position and brightness 
                              of the object in question.                
           Ķ
            Measure Position  Display  the current  image  in  order to 
                              measure  the  position of  the  reference 
                              stars and the object in question.         
           Ķ
            Measure           Display  the current  image  in  order to 
            Position & Mag    measure the position  and  brightness  of 
                              the  reference  stars  and  the object in 
                              question.                                 
           Ķ
            Remeasure Object  Remeasure the object  without remeasuring 
                              the reference stars.                      
  Ķ
   Utility  Scale             Scale  the  image  so  that  a  specified 
                              percentage  of  pixels appear  black (Low 
                              Limit) and white (High Limit).            
           Ķ
            Smooth            Apply a mean value filter to the image.   
           Ķ
            Median Filter     Apply a median filter to the image.  This 
                              removes  speckles and  noise  just as the 
                              mean  value  filter  does,   but  without 
                              sacrificing image sharpness.              
           Ķ
            Blink Images      Compares two images by blinking them.     
           Ķ
            Edit Parameters   Edit  information  on the  image which is 
                              important  for  astrometric  work.   This 
                              function  will  also  be called  after an 
                              image has been loaded from the disk.      
  Ķ
   Ephem    Load Elements     Load orbital elements  from the disk into 
                              the main memory.                          
           Ķ
            Save Elements     Save the current set of  orbital elements 
                              to disk.                                  
           Ķ
            Discard Elements  Remove the  current orbital elements from 
                              the main memory.                          
           Ķ
            Calculate         Calculate an  ephemeris from the  current 
                              set of orbital elements for a given time, 
                              at  the  end of  evening  twilight or the 
                              beginning of morning twilight.            
           Ķ
            Scan Elements     Scan the orbital elements on the disk and 
                              display a "what's up tonight" listing.    
           Ķ
            Display Elements  Displays the current set of elements.     
           Ķ
            Edit Elements     Edit orbital elements.                    
  Ķ
   Options  Directories       Set paths  for the  CCD images,  GSC-data 
                              and ephemeris-files.                      
           Ķ
            Observatory       Set default  information on the  location 
                              and equipment of the observatory.         
           Ķ
            CCD               Set default information on your CCD.      
           Ķ
            Delta T           Set the default value for  T = TDT - UT, 
                              used while calculating an ephemeris.      
           Ķ
            User              Set default information on the user.      
  Ķ
   Windows  Resize/Move       Change the size or position of the active 
                              window.                                   
           Ķ
            Zoom              Enlarge or restore the size of the active 
                              window.                                   
           Ķ
            Next              Make the next window active.              
           Ķ
            Close             Close the active window.                  
           Ķ
            Tile              Arrange windows by tiling.                
           Ķ
            Cascade           Arrange windows by cascading.             
  Ķ
   About    About             Display information about "Astrometrica". 
            Astrometrica                                                
           Ķ
            License Info      Display license information.              
  ͼ


  USING "ASTROMETRICA"
  

  Setup
  

  When you use  "Astrometrica"  for the first time, you should go trough the
  'Options'-menue at first. The 'Directory'-subcommand allows you to specify
  the path where the CCD images are stored, the CD-ROM-drive where to search
  for the GSC-data  (or a  subdirectory on a  hard disk,  with the same tree
  of subdirectories as on the CD-ROM)  and the path where the files  holding
  the orbital elements can be found.

  The 'Observatory'-subcommand is used to set the default information on the
  location  and  equipment  of your  observatory,  which is used  during the
  calculation of an ephemeris and the preparation of the REPORT-file.

  The 'CCD'  submenue  allows you  to specify  weather you want to use  ST-4,
  ST-6 or TIFF images.  The spectral band in which your CCD camera works  can
  also be selected here.  While many CCDs  (like the ST-4 and ST-6)  are most
  sensitive  for  red light,  when you don't use filters,  a sensitivity  for
  visual light would be desireable, as the magnitudes given by the GSC are V-
  magnitudes.
  If you use a camera other than the ST-4 or ST-6,  you should also enter the
  pixel size and the focal length of the telescope you use.

  The 'Delta T'-subcommand allows you  to set  the value for  T = TDT - UT,
  which is used while  calculating an ephemeris to convert universal time to
  dynamical time and vice versa.

  The 'User'-Subcommand asks you  for your name and your adress,  which will
  appear in the REPORT-file.


  The Status Window
  

  The status  window  appears  on the  bottom of the  desktop when you start
  "Astrometrica". Like other windows, it can be moved around,  but you can't
  close it. It shows the filename  of the image loaded,  the filename of the
  color table loaded, the filters applied to the current image, the filename
  of the  current  orbital  elements,  and the  number of selected reference
  stars held in the  computers  main memory.  In some cases,  short messages
  appear within the status window.


  Loading Images
  

  Using the 'Load Image'-command from the File-menue,  you can load the CCD-
  images you want to measure. Version 2.0 of "Astrometrica" reads ST-4, ST-6
  and uncompressed 8 bit gray-scale TIFF images.

  After the image  has been loaded,  the most important  parameters  will be
  displayed  and may be changed,  if  neccessary.  "Astrometrica"  tries  to
  calculate the time of mid-exposure, in case of ST-6 images, by adding half
  the exposure time used to the time  when the exposure was started. As this
  time is taken from the header  of the image file,  it depends on the clock
  of the computer that was used while taking the images.

  CAUTION:  When loading an image taken with the ST6 'Track and Accumulate'-
  mode, the time of mid-exposure can  NOT BE CALCULATED CORRECTLY!  You have
  to calculate the time of  mide-exposure manually by averaging the times of
  mid-exposure of the individual images.

  In case of ST-4 images, "Astrometrica" tries to isolate date and time from
  the comment string,  and substracts half the exposure  from that time,  as
  the ST-4 saves the time when the exposure ended.

  With sufficient memory, it is possible to load TIFF images up to 512 x 256
  pixels in size.  Even larger images, up to 1024 x 512 pixels, can be read.
  Then, four pixels will be combined internally in order to divide the image
  dimensions in half.  As  TIFF  images  give no information on the exposure
  time, the time of mid-exposure can not be calculated.

  ALWAYS check the  date and universal time (UT)  of mid-exposure carefully,
  no matter which camera you use!


  Filtering Images
  

  The  'Smooth'  function  and the  'Median Ffilter'  can be used to  remove
  specks  in the image or reduce  the effects of noise.  The smooth function
  applies  a mean value filter  to the image,  which sets the  gray value of
  each  pixel  to the  mean  value of the  pixel  itself  and  its  adjected
  neighbours, which blurs the image a bit.

  The median filter removes specks and noise without sacrifying sharpness by
  setting  the  gray value  of  each  pixel to the  median of itself and its
  adjected  neighbours.   However,  it  takes  about  three times  longer to
  process the image this way as with the smooth function.

  Be  careful  when measuring images processed by filters other than the two
  mentioned above!  Some filters,  such as high pass filters  ('Sharpening'-
  filters),  unsharp masking or convolution methods may modify  the image in
  a way that the calculation of the centeroid of an image is influenced.

  Scaling of images may influence the results, too. Linear scaling (which is
  necessary to create 8 Bit TIFF images from 16 Bit image data, for example)
  does not much harm,  when  you try  not to loose  much information.  Other
  methods,  like  logarithmic scaling,  should not be used on the images you
  want to measure.

  The scaling function of  "Astrometrica",  by the way,  does not change the
  values of the  pixels in the image,  and therefore may be used  safely. It
  just sets the display parameters (background and range)  so that the image
  may be viewed at optimum contrast.

  In general, try using unfiltered and unscaled images for astrometric work.


  Compare Images
  

  By using the 'Blink Images' command of the 'Utility' menu,  two CCD images
  can be compared, in order to detect moving or variable objects. First, the
  file holding the comparison image must be selected.  Then you have to mark
  a reference point (a bright star, for example) on both images  by clicking
  on it, so the images can be aligned.

  For comparison,  the images  will be displayed alternately.  The time each
  image will be displayed  can be controlled  by the keys '0' to '9',  where
  pressing the key '1'  means that each image  will be displayed  for  50ms,
  while it will be displayed  for 450ms  when you press '9'.  After pressing
  '0', each image  will be  displayed  until  the user  allows  switching by
  pressing any key.

  Pressing the Escape-key exits the blinking procedure.


  Selecting Reference Stars
  

  By issuing the 'Measure - Select Reference Stars' Command,  you can select
  the reference stars,  whose data from the  GSC are later used to calculate
  the position and brightness of the object in question.

  From the time  stored with the CCD image  and from  orbital elements,  the
  computer is able to select the region of the sky so that the chart and the
  CCD image  can be displayed  at the same scale,  where the aspect ratio of
  the chart  will be set  to  fit  that  of  the CCD image.  If there are no
  orbital elements loaded,  the user has to enter the position of the object
  at the time the image was taken.

  If you have rotated the camera  so that north is not up in the image,  you
  can compensate this field Rotation,  so the cahrt and the CCD image may be
  displayed with the same orientation.

  You can also select reference stars from a chart  drawn after you selected
  the  'Display - Chart'  command.  You have to care for the  coordinates of
  the field then. While the computer gives you a suggestion for the scale of
  the chart to fit the CCD image,  the aspect ratio of the chart will not be
  changed to fit the CCD image.

  Select reference stars,  which are neither under-  (hardly distinguishable
  from  the background noise)  nor over-exposed  (with a saturation of 100%,
  or,  in other words,  with a pixel-value  of 65535 for 16 bit images).  If
  possible, select seven to ten reference stars which are evenly distributed
  around the object.


  Measuring an image
  

  Before you use  CCD images  for  astrometric purposes,  substract the dark
  frame  and  apply  the  flat field correction  to the image.  It should be
  possible to display the image  in a way  that the stars and the object you
  want  to measure  appear  on a uniform,  dark  background.   Otherwise,  a
  longer integration time  may be necessary.  On  the  other  hand,  neither
  the reference stars  nor the object  you want  to measure  should be over-
  exposed (e.g. with a saturation of 100%).

  After  selecting  the   'Measure Position'-  or  'Measure Position & Mag'-
  command, the current CCD image will be displayed and a box,  which is used
  to measure the  position  and  magnitude  of the stars on the image,  will
  appear.  The size of this box may be changed using the keys  F1 to F4,  so
  it will fit the images of the objects to be measured: Using the  F1 and F2
  keys, the x-size of the box can be decreased and increased,  respectively,
  while the  F3 and F4  keys can be used to decrease and increase the y-size
  of the box.

  A small window  displayed  below  the  image  gives you information on the
  location of the box (x,y coordinates), the saturation of the central pixel
  in percent, and the boxsize.

  Before the object of interest and the refernce stars can be measured,  the
  brightness  of  the  backgound-sky  has to be  determined.  In order to to
  this,  move the box to a region  free of nebulae and stars,  and press the
  Enter key. If the background does not appear uniformly bright, measure the
  brightness of the background near the object of interest.

  If you have selected the 'Measure Position & Mag'-command,  the brightness
  of the  object of interest  will be measured next.  Locate the box so that
  the object lies completely within this box  -  including the faint,  outer
  coma in case  of comets  -  and press  the Enter key again.  If the faint,
  outer region  of a comet's coma  has not been recorded  because of a short
  integration time,  the magnitude  of the comet  may be under-estimated  by
  several magnitudes!

  Then, the position of the object of interest will be measured.  Locate the
  box so that the  centeroid of light  lies near  the middle of the box.  In
  case of comets,  you  may  "cut off"  the coma  and  take into account the
  nucleus of the object only.

  Now, the reference stars will be measured. Locate the box so that the com-
  plete image  of each star  lies within  the box.  If you have selected the
  'Measure Position & Mag'-command,  the position and brightness will be me-
  asured simultaneously.

  After the measurement has been completed,  the positions and magnitudes of
  the reference stars  and the object will be calculated.  The brightness is
  calculated  from a linear regression  between the measured intensities and
  the intensities calculated from the entries in the GSC. Using the measured
  positions of the reference stars,  the plate constants a, b, c, d, e, f, g
  and h will be calculated. With their help, it is possible to calculate the
  rectangular standard coordinates X and Y from the measured positions x and
  y in the following way:
                          X = a*x + b*y + c*xy + d
                          Y = e*x + f*y + g*xy + h

  In case you have measured only four reference stars, the plate constants c
  and g are set equal to zero. From the rectangular standard coordinates, it
  is finally possible  to calculate the spherical coordinates of the objects
  we are looking for.

  After the calculations described above have been finished, the  results of
  the data reduction  will be  displayed.  For each reference  star  and the
  object of interest, the measured position and magnitude will be shown. For
  the reference stars,  the O-C (observed-calculated) residuals for position
  and  magnitude  will appear,  too.  If you have selected  the 'Measure Po-
  sition'- command,  no  magnitudes  will be given.  The  measured pixel co-
  ordinates of each object will be displayed instead.

  If there are orbital elements loaded,  the O-C residual of the object will
  be shown as compared to the ephemeris.  In contrast to the residuals given
  for  the reference stars,  this value is not the  "true" residual,  as you
  usually measure the position of the object to refine it's orbit,  and thus
  the position of the object can not be calculated precisely.  However,  you
  can compare the value given with that for other images of the same object,
  taken during the same observing session.  This allows you  to make a guess
  of the quality  of the measurements  from the variation  of the residuals.

  The results of the measurement will be summarized in the files REPORT.TXT,
  CREPORT.TXT and ASTROMET.LOG.

  If your image shows more than one minor planet, or if you want to measure,
  for example,  a comet using both a 7 x 7 and a 9 x 9 box,  you may use the
  'Remeasure Object' command, which allows you to measure the object without
  having to measure the background and the reference stars, again.

  If you measure different objects using the 'Remeasure Object' function, do
  not forget to load the corresponding orbital elements, if you want to com-
  pare your results with the ephemeris.  If you have a series of images,  it
  is recommended always to measure the different objects in the same order.


  Results
  

  Since the beginning of its developement,  "Astrometrica"  has been used by
  the author and his  collegue  Erich Meyer.  Using a ST-6 CCD camera on the
  Schmidt-Cassegrain telescope  (288mm diameter, 1500mm focal length) of the
  private observatory Obermair/Meyer, which lies near Linz, Austria, Europe,
  at 48.4425 northern latitude, 14.2753 eastern longitude,  815m above the
  sea level,  roughly 500 precise positions of comets and minor planets have
  been measured within one year, starting in March, 1993. These observations
  have been published in the  IAU Circulars and Minor Plabet Circulars under
  the observatory code 540.

  Although the pixel size is 3.5" x 3.7" at the focal length of 1500mm,  the
  mean residual of the reference stars has been setteled near  0.15" per co-
  ordinate.  However, these residuals are minimized by the least square fit.
  Furthermore,  there are systematical errors within the GSC.  Therefore, we
  may expect higher residuals for the objects we measure.  But how large are
  these errors?

  On Minor Planet Circular 22962, published on January 27, 1994, the results
  of the orbital calculations for minor planet 1993WD are given.  Of the 101
  astrometric observations of the object made between Nov. 13, 1993 and Dec.
  18, 1993, 89 have been used in the calculation of the orbit.  The mean re-
  sidual of all the observations is 0.73" per coordinate,  the largest total
  error is 6.5"
  All the 17 observations we made within this time,  using the equipment de-
  scribed above, have been used in the orbital solution, their mean error is
  0.57"  per coordinate (which corresponds to only 0.17 pixels).  Of our ob-
  servations, 12 (71%) had a total residual of less than  1.0", 14 (82%) had
  a total residual  of less  than 1.5",  and the largest  total residual was
  only 1.9".

  These results are possible  due  to  the  calculation  of the centeroid of
  light.  However,  to calculate it,  the images  of the stars  must cover a
  minimum amount of pixels.  A short focal length  or  extremly  sharp  star
  images will therefore negatively influence the results.  Keep in mind that
  unfavorable observing conditions, like moderate seeing or light pollution,
  decrease your limiting magnitude, but do hardly harm the quality of astro-
  metric measurements.


  Editing orbital Elements
  

  After selecting 'Ephem - Edit Elements' from the Menue, you have to decide
  weather  you want  to edit  the  orbital  elements  of a comet  or a minor
  planet.  If there is  already  a set of orbital elements loaded,  only the
  selection which does not conflict with these elements is possible.  Before
  you  load,  or key in,  any elements,  or  after  selecting  the  'Discard
  Elements' command, both selections are possible.

  The field  asking for the name  of the object  is split in two parts.  The
  firts part may be used to enter a name or number for the object, while the
  second part  may be used  to enter  a short name  (see informations on the
  file 'CREPORT.TXT'). In case you don't need the CREPORT-file, which uses a
  standard format for reporting astrometric observations,  this field may be
  left blank.

  The orbital elements  you key in now  may be given for any aequinox:  They
  will be converted to the standard epoch J2000.0 by the program.


  Calculatin an ephemeris
  

  "Astrometrica"  can calculate  a detailed ephemeris  from orbital elements
  keyed  in  by  the  user  or  read from  the  disk.  The ephemeris  may be
  calculated for  a given instance of time,  for the end of the astronomical
  evening twilight or the beginning of the astronomical morning twilight.

  The following information is given:

  Date, U.T. .... Date  and  universal Time for which the following data are
                  valid.

  R.A., Decl. ... Aequatorial coordinates of the object (J2000.0).

  Alt, Az ....... Horizontal coordiantes of the object.

  El ............ Elongation of the object from the Sun.

  Moon .......... Angular distance of the object from the Moon.  An asterisk
                  is printed  if the moon is above the horizon  at the given
                  instant.

  k ............. Illuminated fraction of the moon's disk in percent.

  mag ........... Predicted magnitude of the object.

  Ph ............ Phase angle of the object. (For minor planets only.)

  Tail .......... Predicted  position angle  of  the  ion-tail.  (For comets
                  only.)

  r, d .......... Distance of the object  to Sun  and Earth  in Astronomical
                  Units.

  , P.A. ....... Appearent motion  of the object:  Angular speed in arcsec.
                  per minute, position angle of the direction of motion.

  t ............. Period for the motor  which is used  to compensate for the
                  motion of the object. (The period at 1"/min may be entered
                  using the 'Options/Observatory' command.)


  The file 'CREPORT.TXT'
  

  This file  holds the data  from the astrometric observations  according to
  the standard format given on M.P.C. 18847 to 18849 (October 1991)  and may
  be used  for sending astrometric observations  via computer networks or on
  diskette.  (CREPORT stands for Computerized Report.)  In this format,  the
  object is  identified  by a short name,  which you can enter  when editing
  orbital elements. Here are a few examples (most are taken from the October
  1991 M.P.C.s) which illustrate how to use the short name:

  Name:   [Ceres     ] [00001     ]  --  Minor Planet (1) "Ceres"
                                         Note the leading zeros!

  Name:   [1990HV4   ] [J90H04V   ]  --  Minor Planet 1990 HV4
                                         J for century digit 19

  Name:   [2000YZ109 ] [K00YA9Z   ]  --  Minor Planet 2000 YZ109
                                         5th digit A for 10

  Name:   [P/Halley  ] [J8603J820i]  --  Comet 1986III = 1982i "P/Halley"

  Name:   [1988 XVIII] [J8818J871c]  --  Comet 1988 XVIII = 1987c1

  Name:   [1993e     ] [J930e     ]  --  Comet 1993e "P/Shoemaker-Levy 9"
                                         No definite designation yet

  Name:   [P/Encke   ] [J9021    `]  --  Comet 1990XXI "P/Encke"
                                         No provisional designation
                                         ` marks a comet

  Take care to enter the short name correctly!


  COPYRIGHT
  

  The copyright and all other rights are owned by the author:

  Herbert Raab
  Schrammlstr. 8
  A-4050 Traun
  Austria

  "Astrometrica" was implemented using Borland Pascal 7.0 (c).
  The user interface is based on Borland's Turbo Vision 2.0 (c).

  Brand and product names  mentioned  in the text are  usually trademarks or
  registered trademarks of their respective holders.


  DISCLAIMER
  

  "Astrometrica"  is  supplied as is.  The author  disclaims all warranties,
  expressed or implied, including, without limitation,  the warranty of fit-
  ness for any purpose. The author assumes no liability for damages,  direct
  or consequential, which may result from the use of "Astrometrica".

  However,  I tried hard to write  a program which is  easy to use  and does
  what you want it to do. Months of using it have shown that "Astrometrica",
  in  combination  with  modern CCDs   is a powerful instrument  which gives
  amateur astronomers the possibility to do scientific work on minor planets
  and comets.

  If you have discovered a bug or have any ideas for future releases of this
  software, please let me know!


                                           Have fun with "Astrometrica" !

                                                    Herbert Raab
