AOS.EXE Version 2.5 by DK1TB
  ===============================

  Thanks to Erich Eichmann, DK1TB who has made his AOS.EXE, which was
  first released in 1994 Y2K compliant.
  
  This new version should run on all MS-DOS and DR-DOS versions and also 
  on any Windows platform and should have no problems in loading any files 
  with Keplerian data, if edited or not. 

  Please report if the program runs flawless and if it is of any use for
  you, thank you.

  Comments and any correspondence please to:
  Erich Eichmann, DK1TB, DK1TB@amsat.org
  or
  Reinhard Richter, DJ1KM@amsat.org


  How to get started
  ==================
  AOS.EXE is written by DK1TB and is freeware for Amateur Radio use only.
  It is an derivatet from his version SAT-PC which is widely in
  use in Germany, but unfortunately available in German language only,
  distributed by AMSAT-DL Warenvertrieb. To make it understandable to the
  outer world DJ1KM has translated it into English. However, date format 
  in the lists is shown in German order as dd-mm-yyyy and cannot not be 
  changed to a different kind of writing, sorry.

  AOS.EXE creates lists (similar to SORT.DMP) in chronological order to
  screen, to printer or into a file. Such kind of list is very helpful for
  an operator for listening to his favorite sat to plan his coffeebreak
  accordingly if he always carries the printout with him. Also if you take a
  two weeks list with you for your vacation to make your xyl happy showing
  her how busy you would have been at home with that many various satellites.

  The program is using Keplerian data files in 2-line NASA format as well
  as in AMSAT format. There is no need to remove other text from the
  original files. However, if you wish to have only certain satellites in
  your list you must remove the other satellites from the data file by using
  an ASCII editor. Be careful to have always complete data sets in that
  file. Example files are supplied, one each in NASA2LINE format and 
  in AMSAT format and one with three satellites only. 

  Before running the program you must enter some personal parameters. Call
  "Tools" first and make your selections in "Path", "Mask", "Location"
  and "Time Offset". Also select if you like to have the list output in UTC
  or local time.

  For correct calculation your location is required. Therefore your personal
  geographical coordinates have to be entered into the program.

  You have the choice of entering your (Maidenhead) grid locator or your
  decimal coordinates. If you choose the latter press just <RETURN> when the
  program asks for Locator.

  Longitude must be entered in eastern sense, southern latidudes require a
  minus sign. Minutes have to be entered as decimal figure.
  Example:
  10 degree 45 minutes southern latitude = -10.75.
  96 degree 12 minutes western longitude = 263.80 (360 - 96.20). 

  The list displays AOS, LOS, duration of a pass in minutes and maximum
  elevation of a pass together with azimuth at AOS based on the location of
  the user. In the header the day # is indicated in AMSAT count. By choice
  you can have the listing in UTC or local time. Depending on your selection
  letters L for local or U for UTC are displayed in the header of the list
  between AOS and LOS time, and also in the Main Menue right behind the time
  in the upper right corner. Local time is the time your computer is set to.

  We have received some reports on the accuracy of AOS.EXE when compared
  with sort.dmp created by IT. First please remember that the intention of
  AOS.EXE is to give you an aid for your satellite activity so that you
  can print lists and can check what will happen in the next hours or days
  with your favourite satellites. For this purpose extreme high accuracy is
  not required. To make the calculation run fast it is programmed like this:

  The program searches in 5-minute steps for the next satellite. If the pass
  duration of any satellite is less than 5 minutes this sat may be but must
  not skipped. It depends on if the 5 minutes step lays inside this short
  pass or not. If the program found a satellite in the 5 minute window it
  returns to the last step and starts searching in 1 minute spaces. It stops
  as soon it notices a change between minus and plus elevation and writes
  this value to disk. Thus the tolerance is 1 minute only, not seconds. Then
  the program advances further in 1 minute steps till it sees the highest
  elevation. Especially at overhead passes the max. elevation will vary very
  fast within 1 minute.  At lower passes the variation is only small. The
  snapshot is not done at second steps but in minute steps. So it can happen
  that it will not meet the absolute highest elevation but that elevation
  only at the specific 1 minute step. Actually this is not important because
  the user should just know that the elevation will become rather high.
  Together with the duration of a pass he can decide if the pass is useful
  for him or not. The LOS value will be determined the same way. First in 5
  minute steps and the in 1 minute steps. With phase 3 satellites the steps
  are 15 minutes.

  If you don't like the colors you may wish to alter them to your taste.
  Editing AOSPER.SQF by using an ASCII editor replace the numbers in line 7
  for foreground and in line 8 for background. Use numbers from 0 to 15 as
  given in the file 'color.txt'.

  Have fun!

  Erich Eichmann, DK1TB