
        QuickSat Satellite Prediction Program
        Version 2.15N            June 4, 2010


        Description of the Documentation

This documentation consists of the following parts:

1. Introduction                                     line  20
2. Operation of the program                         line  69
3. How to run the test                              line 128
4. Description of the control file                  line 144
5. Description of the intrinsic magnitudes file(s)  line 577
6. Description of the orbital elements file(s)      line 670
7. Description of the prediction output             line 708



        Introduction

This program has gradually evolved over many years.  Its purpose has always
been to support visual observations of satellites.  For that reason, the
normal execution of the program produces a single prediction for each
satellite.  That prediction point is the culmination point if that point is
outside the Earth's shadow.  Otherwise, a point outside the Earth's shadow
that is nearest the culmination point is chosen.  Multiple predictions for
each satellite may also be chosen.  The prediction of an object's magnitude
is a primary goal.  The probable error in time of prediction is computed by
a heuristic.  The observer may create his own "intrinsic magnitudes override"
file so that his own information will "override" the information in the
default "intrinsic magnitudes" file.  There is a "radio" predictions flag
that will bypass all of the parts of the program having to do with magnitudes,
the Earth's shadow, RA and Dec.

This program is freeware.  There are no restrictions on its distribution.

The program is written in Fortran. This version requires the use of a
coprocessor.  This is a "DOS" program.

The program has certain "built-in" limits:  1) No more than 5000 names and
magnitudes may be stored from the "intrinsic magnitudes" file.  2) If the
"store elements in memory" option is chosen, no more than 5000 element sets
may be stored from the orbital elements files.  3) No more than 600 different
set of "size" values can be stored.

The following files are provided:
1. quicksat.txt - this file
2. quicksat.exe - the executable
3. quicksat.mag - a file of intrinsic magnitudes, sizes, and RCS values
4. quicksat.ctl - an input test control file
5. quicksat.dat - an input test elements file (these elsets are 11 years old)
6. quicksat.ref - the output file from the test

The author of the program is Mike McCants.  I can be reached at
"mmccants@io.com" on the Internet.  The current version of Quicksat is
located in my ftp area, which can be accessed from my home page.
(http://www.io.com/~mmccants/)

Changes for version 2.15N:  This is a 32-bit executable.  It was generated
by using f2c to convert the Fortran files to C and then by using Digital
Mars C to generate the program.  The limit on the number of input tles has
been increased to 5000.  The limit on the number of satellite names has
been increased to 5000.  The limit on the number of output predictions
that can be generated has been increased to 5000.



        Operation of the Program


The user is expected to operate the program in the following way:

I. Input data preparation
   1. Orbital elements are obtained.  Note: the elements file must have
      a carriage return character at the end of each line.  If you obtain
      a file from kilroy.jpl.nasa.gov/pub/elements and you fail to add
      a carriage return character to the end of each line, the message
      "no elements were loaded" will be printed.  The program ADDCR can
      be used with the command "ADDCR input-file output-file".
   2. Optionally, names, intrinsic magnitude, sizes, or comments
      can be added to an "intrinsic magnitudes override" file.

II. Control file preparation
   1. The control file is edited to specify either "tonight" or the year,
      month and day (or zero) for the time of predictions, the latitude
      and longitude for the observing site, and the name(s) of the satellite
      elements input file(s).

III. Program execution
   1. The program is executed.  (This is a DOS program.)
   2. The name of the control file to be used can be placed on the command
      line as a single parameter.  If no control file is specified on the
      command line and there is a control file named QUICKSAT.CTL in the
      current directory, then that file is used.  If there is not a file
      named QUICKSAT.CTL in the current directory, the program prompts for
      the name of the control file to be used.
   3. As determined by the control file, the user may be requested for the
      day of the month for the desired predictions.
   4. As determined by the control file, the user may be requested to enter
      up to 20 NCAT numbers of objects to be predicted for.
   5. As determined by the control file, the user may be requested for the
      name of the file to contain output.
   6. As determined by the control file, the user may be requested for the
      name of a file containing orbital elements.

IV. After the program completes, the output file may then be printed or
    displayed.

The program operates in the following way:

1. The control file is read.
2. The intrinsic magnitudes data is read into memory.
   (Note: the program will continue even if this file is not present.)
3. The intrinsic magnitudes override data is read into memory.
4. The orbital elements are read into memory (if the "store elements
   in memory" flag is true).
5. All predictions for the first night are generated and stored in memory.
6. The predictions are sorted into time order and written to the output file.
Steps 5 and 6 are repeated for subsequent days.

However, if a "combine" operation is specified, predictions for only one night
should be specified and steps 1, 4, and 5 are repeated for each set of control
lines.  Then step 6 is performed.



        How to Run the Test


1. Enter QUICKSAT to execute the program.

2. Compare the generated file, OUTPUT.TXT to the reference file, QUICKSAT.REF.

Note:  Of course, lower case file names may be used, upper case is shown here
for clarity.

Note: the elements in the QUICKSAT.DAT test file are from 1990 and the
test output is for 1990.  You must obtain current elements in order to
compute current predictions.



        Description of the Control File


This file controls the operation of the program.  If the name of a control
file is entered on the command line, that file is processed.  If no filename
parameter is given and a control file named QUICKSAT.CTL exists in the
current directory, it will be used.  If not, the user will be prompted to
enter the name of the control file to be used.

There are at least 21 lines in this file.  Each will be described in turn.

NOTE:  Each line is in a "free form" format.  Values may be separated by
spaces or a comma.  Comments may be placed after the data values.

NOTE:  Two or more complete sets of control information may be "combined"
so that a single output file will contain output generated by any of them.

Example test input control file (QUICKSAT.CTL):

1990  7 Year, month number
26 0 Start date, end date
-0.3 -5.5   Start time, end time, "A" flag
30.3340  97.7600  520.  5105 Crestway Dr.
-5 CDT 12 correction for UT to time zone, time zone name, 12/24 flag
2000 Epoch of predicted RA, Dec
6.5 Magnitude limit
15 Altitude cut-off value
1.0 The search/step parameter value
T True means store all elements in memory
T True means accept only the most recent elements for each object
F True means ignore shadow test
T  1 True means generate multiple prediction points, how many each way
T True means output distance values in miles
T True means generate a blank line before each object's prediction.
           Up to 10 non-blank flags to select class(es) of objects
A        Output format flag, R/P option, D/C/N option, Azimuth option
quicksat.mag      Intrinsic magnitudes input file
none              Intrinsic magnitudes override file
output.txt        Output file
quicksat.dat      Elements input file
EOF               End of input file list


Line 1:  This line is either the word "tonight" or the year and
         month number.

tonight  Use current computer date
1990  7 Year, month number

If the word "tonight" appears in lower case, then the current computer
date will be used to obtain the year, month, and day. In this case,
line 2 must NOT be present in the control file.  Note: the computer time
is ignored.  If it is 1AM on the 18th, predictions will be generated
for the evening of the 18th and/or the morning of the 19th, not for the
morning of the 18th.


Line 2:  This line gives the dates for prediction.

26  0 Start date, end date

Note: if line 1 has the word "tonight", line 2 must NOT be present.

The first number is first day for predictions, the second number is the
last day for predictions.  An end date of zero means perform predictions
for only one day.  If the start date is specified as zero, the user will
be prompted and asked to supply the start date and stop date from the
terminal.  If only one number is entered, predictions for only that day
will be performed.

NOTE:  Due to the way the date is used in the program, the user must NORMALLY
enter the date which ENDS at midnight.  In the test case, the number 26 is
given as the date.  This means that predictions will be performed for the
evening of July 26 and the morning of July 27.  July 26 was a Thursday.  The
title, "July 26  Thu evening", will appear at the top of the predictions.
The user should ALWAYS double check to make sure that a one day error is
not being made.

If it is desired to run predictions for only the morning of July 27, then
the date must STILL be entered as 26.  The start time, end time values
should be changed to +5.5, +0.3 to run morning predictions only.

Note:  This is NOT the case if the "A" flag is set or the "radio" predictions
flag is set.  In these cases, the actual UT date must be entered.


Line 3:  This line specifies the prediction time limits and the "A" flag.

-0.3 -5.5   Start time, end time, "A" flag

The prediction time limits values are in hours.  A negative number means
"before", a positive number means "after".  Unless "absolute" mode or "radio"
predictions mode has been specified, the reference times are the times that
the sun is 10 degrees below the observer's horizon.  Therefore a value of
-0.3 means begin predictions 18 minutes BEFORE the time that the sun is 10
degrees below the observer's horizon in the EVENING.  A value of -5.5 means
end the predictions at the time which is 5 hours 30 minutes BEFORE the time
the sun is 10 degrees below the observer's horizon in the MORNING.  These
10 degree reference times are printed as part of the output title.

To run evening predictions, a span of 0 to -6 is appropriate.  To run morning
predictions, a span of +6 to 0 is appropriate.  A span of 0 to 0 runs
predictions for both morning and evening.  But, of course, the "-6" value
depends greatly on the latitude and time of year.

If the start/stop times are followed by the letter "A", then absolute times
(UT) are specified.

If The "A" flag or "radio" predictions have been specified, then these times
are relative to zero hours UT.  That is, -5.0 +2.0 would be a 7 hour span
beginning 5 hours before 0 hours UT and ending 2 hours after 0 hours UT.
Remember, in these cases, the start date is the actual UT date.


Line 4:  This line gives the latitude, longitude, height, and site name
of the observer.

30.334  97.760  520.  5105 Crestway Dr.

The site name text can be up to 24 characters in length.
The longitude is positive for WEST longitude, negative for east longitude.
Note that this is the opposite from most prediction programs.
Height is in feet.


Line 5:  This line gives the UT correction value, the time zone name,
         and the 12/24 hour flag.

-5 CDT 12 Correction for UT to time zone, time zone name, 12/24 flag

The time zone correction value is added to the UT time of prediction to
produce a local time of prediction.  If the resulting value is zero or
negative, 24 will be added to make it greater than zero.  If the resulting
value is greater than or equal to 24, then 24 will be subtracted.  In
either case, the date will be adjusted.  The result is a time from 0 to 23.
The designation AM or PM is based on this value.

If the 12/24 flag is not 12, then this result is the output.  If the flag
is 12, then the time value is adjusted to be from 1 to 12.


Line 6:  This line gives the epoch of the RA and Dec values.

2000 Epoch of RA, Dec


Line 7:  This line gives the "cut-off" magnitude.

6.5 Magnitude limit

Any prediction whose magnitude is fainter than the "cut-off" magnitude
will be suppressed.  If the intrinsic magnitude of an object is unknown
but an RCS value is known, then an intrinsic magnitude for the object will
be computed from the RCS value for use by this "cut-off" test.  If the
RCS value is unknown, then the intrinsic magnitude is assumed to be either
4.0 or 7.0 for this magnitude limit test.  For objects whose NORAD catalog
number is less than or equal to the "7.0 test value", an intrinsic magnitude
of 7.0 is assumed.  For objects with a greater number, 4.0 is assumed.


Line 8:  This line gives the altitude "cut-off" value.

15 Altitude cut-off value

Any prediction which has an altitude below this "cut-off" value will be
suppressed.


Line 9:  This line gives the search/step parameter value.

1.0 The search/step parameter value

This parameter value is used as a "step size" value in two situations.
If multiple points of prediction are specified, this value gives the step
size between each.  If the culmination point is inside the Earth's shadow,
then 1/2 of this value is used as the step size to search for a point that
is outside of the Earth's shadow.

If multiple points of prediction are specified, this parameter should be
adjusted to provide the desired spacing between the points.  A value of 1.0
will give the following results:  For an object at 400 miles, about a 1
minute spacing.  For an object at 600 miles, about a 1:30 spacing.  For an
object at 1000 miles, about a 2 minute spacing.  If an object will pass
through the observer's zenith, then a step size of 1.0 will give predictions
at an altitude of about 50 degrees before and after the zenith prediction.

If multiple points of prediction are not specified, 1/2 of the value is
used to search for a position that is about 20 miles outside of the Earth's
shadow.  Thus a smaller search size value would require more computation,
but would often find a point higher in the sky that has a shadow height
of more than 20 miles.


Line 10:  This line gives the "store elements in memory" flag.

T True means store all elements in memory

If this flag is true, elements are read from the input file(s) and
stored in memory.  No more than 5000 elements may be stored.  The
"keep only the most recent elements" flag works across files.

If this flag is false, elements are read in and processed, so there is
no limit on the number of elements that can be processed.  However,
the "keep only the most recent elements" works only when the multiple
element sets for an object are grouped together in an element file.
If the elements for an object are not together in the file or appear
in multiple files, then multiple predictions will be generated.


Line 11:  This line gives the "keep only the most recent elements" flag.

T True means keep only the most recent elements for each object

If this flag is false, all elements in all input files will be accepted
for predictions.  If there are duplicate element sets for an object, then
there will be multiple predictions for that object.  If this flag is true,
each element set will be checked to see if it is for the same object as an
element set already read in.  If so, then the element set which has the
older epoch will be discarded.  Thus only the latest data for each object
will remain for prediction purposes.  But, see limitations on this process
described under line 10.


Line 12:  This line gives the shadow test flag.

F True means ignore shadow test

If this flag is false, no prediction will be generated for any point
where the height of the object is less than about 20 miles above the
Earth's shadow.  If this flag is true, such prediction points will not be
suppressed, so predictions inside the Earth's shadow will be generated.
Such predictions will have negative shadow height values.


Line 13:  This line has the multiple points flag (T/F) and the limit on
          the number of points that will be generated.

T  1 True means generate multiple prediction points, how many each way

If this flag is false, only one prediction point will be generated for each
pass of each object.  If this flag is true, multiple points may be generated.
Each point must satisfy the shadow test, altitude cut-off, and magnitude
cut-off.  The time difference between the points is determined by the step
size parameter value and the object's mean height.  The number of points
is the limit on how many points can be generated "on each side" of the
culmination prediction.  In the normal case, a value of 1 will generate
3 prediction points - the culmination point and one point both before and
after it.  However, if the culmination point is in the Earth's shadow, then
only one point will be generated.  Similarly, a value of 2 would normally
generate 5 points, but could generate only 1 or 2.

Note: a value of 99 means "no limit".

Note: the step size parameter is the value on line 9.


Line 14:  This line specifies the miles/kilometers flag.

T True means output distance values in miles


Line 15:  This line specifies the blank line flag.

T True means generate a blank line before each object's prediction.


Line 16:  This line specifies flags for "classes" of objects.
          Or specific NCAT numbers may be entered from the terminal.
          Or alt/azi or RA/dec output limits may be specified.

    1. Classes of objects

f t s      Up to 10 non-blank flags to select class(es) of objects

If there are no classes specified, then all objects will be predicted for.
If there are non-blank characters for the classes, then only those objects
which have one of these characters as their "flag" value will be predicted
for.  In general, "c" means a classified object, "f" or "t" means a tumbling
object whose tumble period is of interest, and "s" means an object that is
now steady (but has tumbled in the past).  (See the definition of the flag
value in the intrinsic magnitudes file description.)

    2. Specific objects

If the word "prompt" (in lower case) appears in the first 6 columns, then
the prompt "Enter next NCAT number" will be given.  A single NCAT number
can be entered. If the entered value is non-zero, then the prompt will be
repeated.  If a blank or zero is entered, then predictions will be generated
for just the objects specified.  Up to 20 NCAT numbers may be entered.

    3. Limits for a "box"

If the letters "AA" are given in columns 1 and 2, then alt/azi output limits
are read from the next line.  The format for this line is:

all alh azl azh   alt low lim, alt high, azi low, azi high in degrees

The four values, altitude lower limit, altitude upper limit, azimuth lower
limit, and azimuth upper limit are in degrees.  Only predictions which
are inside this "box" will be generated.  Note: the limits 340 and 20
could be specified for a box around azimuth 0.

Note: all other limits are still in effect.  In particular, the altitude
limit (line 8) is still in effect.  The magnitude limit and the Earth's
shadow are still in effect.

Note: it is normally advisable to lower the step size parameter to a "small"
value (line 8) and increase the number of steps (line 13) so that one or
more predictions for an object going through the box will be generated.

If the letters "RD" are given in columns 1 and 2, then RA/dec output limits
are read from the next line.  The format for this line is:

rhl rml rhh rmh dcl dch   RA hrs low, RA mns low, RA hr/mn high, dec low, high

The six values, RA hours/minutes low limit, high limit, dec low limit, and
dec high limit must be specified.  Only predictions which are inside this
"box" will be generated.  The values 23 40 and 0 20 could be used to specify
a box around 0 hours RA.  See notes for AA option above.


Line 17:  This line specifies the output format and options.

12345678901
A          Output format flag, R/P option, D/C/N option, azimuth option,
           Range Limit option

The standard output format is A.  Each set of predictions for an object is
preceded by a title line containing the name, sizes, intrinsic magnitude, and
comments.  Format D is the same as A except that azimuth is followed by
elevation.  The alternate formats B and C are "one-line" formats where the
name appears on the same line as the prediction.  These formats are described
below.  The format letter must be in upper case.  If the format is A or D and
a D appears in column 5, then the object designation will be printed after the
satellite name.  (The designation comes from the intrinsic magnitudes file.)

If the output format is B or C, then column 3 may contain the letter P indi-
cating that the phase angle is to be printed instead of the range.  If column
5 contains the letter N, then the comments information will not be printed.

If the output format is R, then "radio" predictions will be generated.  There
is no output of magnitude, shadow height, RA, or Dec.

If column 7 contains the letter A, then the azimuth will be adjusted by 180
degrees so that 0 means south, 90 means west, and 180 means north.

If columns 9-10 contain the letters RL, then the range limit value is
specified on the next line.  The range limit is in miles if the miles
flag is true and in kilometers if the miles flag is false.  Any prediction
with a range greater than the specified value will be discarded.

Note: the format flag may be in column 1 or 2, the R/P flag may be in
column 3 or 4, the D/C/N flag may be in column 5 or 6, the azimuth
option flag may be in column 7 or 8, and the range limit flag may be
in columns 9-10 or 10-11.  All letters must be upper case.


Line 18:  This line specifies the intrinsic magnitudes input filename.

quicksat.mag      Intrinsic magnitudes input file

This file contains information on the name and intrinsic magnitude of
objects.  Comments may be retrieved for display with any prediction.
The physical size may also be included.  If this file is not found,
a message will be printed and no such data will be available.
(See further description below.)  The filename must be in columns 1-40.


Line 19:  This line specifies the intrinsic magnitudes override filename.

none              Intrinsic magnitudes override file

This file contains information that will "override" or supplement the
information in the quicksat.mag file.  The format is the same as the
quicksat.mag file.  The NCAT number is required.  Other fields are
optional.  Any non-blank field will override the corresponding field
in the quicksat.mag field.  If there is no entry in the quicksat.mag
file for this object, this entry will be used. (See the intrinsic
magnitude file description below.)  The filename must be in columns 1-40.


Line 20:  This line specifies the output filename.

output.txt        Output file

The name of the output file may be specified.  Alternatively, the
keyword "prompt" may be specified (in lower case). In this case, a
prompt message is issued at the terminal and the user must enter the
output filename.


Line 21:  This line specifies the first orbital elements filename.

quicksat.dat      Elements input file

The name of the first elements file may be specified.  Alternatively,
the keyword "prompt" may be specified (in lower case).  In this case, a
prompt message is issued at the terminal and the user may enter a simgle
elements filename.

The elements file must contain elements in standard "2-line" element form.
Preceding each set of elements, an optional object name may appear.  The
name will be obtained from columns 1-14.  This name will only be used if
there is no entry for the object in the intrinsic magnitudes file.

2-line elements are recognized by the digits 1 or 2 in column 1 followed by
a blank space.  Any lines which do not match this format will be ignored.

Note:  Any element set with a mean motion less than 4.0 will be ignored.
A separate program (HighFly) is available in my ftp area for generating
predictions for these objects.

Note:  If the elements file does not have proper DOS CR/LF characters at
the end of each line, no elsets will be recognized.  If there are no CR
characters at the end of each line, the program ADDCR may be used to add them.

If the keyword "prompt" is NOT present on line 21, then additional input
files may be specified on subsequent lines.  Normally the "T" flag on line
11 would be used to tell the program to keep only the most recent element
set for each object.  The end of the input file list is specified by either
the physical end of the control file or a line which contains "end" or "EOF".

No more than 10 input files may be specified.

If the keyword "combine" is present, then a complete new set of control lines
follows this keyword and the output file will contain the combined results.
Each set of control lines should specify the same site location and the
same (single) day for prediction output.  Each should agree in the type of
output that will be generated.  The intrinsic magnitudes file and the
intrinsic magnitudes override file will not be processed.



        Description of the Intrinsic Magnitudes File


This file contains information about satellites.  Each line contains the
NORAD catalog number, the designation, class, name, size, RCS value and
comments.  A line could be up to 87 characters in length.

The format for the "name" part of the line is:

         1         2         3
1234567890123456789012345678901234567
catno f desig...  name.......... mag.
00005   58 B2     Vanguard 1      9.0

Columns 1-5 contain the NORAD catalog number.

Column 7 contains either a "code" letter or the "class" letter of the object.
The following code letters are used:  "d" means that the object has decayed
or returned.  "h" means that the object is in a high altitude orbit.  The
class letter "c" means the object has a classified orbit.  The class letters
"f" and "t" indicate that the object is of interest because it is tumbling.
The class letter "s" indicates that the object has tumbled in the past, but
is currently steady.  Objects with a "d", "h", or "g" are not stored in memory
by Quicksat.

Columns 9-16 contain the designation.  This information is saved and printed
when the A output format is chosen and the D flag appears in column 6 of
line 16.

Columns 19-32 contain the satellite name.

Columns 34-37 contain the intrinsic magnitude, which is defined to be the
maximum apparent brightness of the satellite when it is seen at full phase
at a range of 1000 kilometers.  The program will adjust this value according
to the actual circumstances of the prediction to determine a maximum possible
apparent magnitude.  Of course many cylindrical objects are often one or two
magnitudes fainter than this predicted magnitude when their actual orientation
is unfavorable on a particular pass.


The format for the "size" part of the line is:

 4         5
901234567890
 7.4 2.4 0.0

The three numbers are the size values.  Many of the values given in this
file were obtained from data posted to the Canadian Space Society BBS by
Ted Molczan.  He normally obtains these values from the RAE Tables.  I have
"adjusted" some of the values to bring the computed intrinsic magnitude into
better agreement with my observations.  Some sizes have been obtained from
Joel Runes' catalog.

If there is only one value, the object is assumed to be a sphere and the
value is its diameter in meters.  If there are two values, the object is
assumed to be a cylinder - the first value is its length and the second
value is its diameter.  If there are three values, then the object is
assumed to be rectangular and the values are for its three sides.


The format for the "RCS" part of the line is:

5
1234
 6.4

The RCS (Radar Cross Section) value is the "median" of all of the "different"
values that appeared in the Satellite Situation Reports from about 5 years
ago to the present.  The RCS value is in square meters, so it should be
closely related to the size values for the object.


The format for the "comments" part of the line is:

5   6         7         8
67890123456789012345678901234567
observational information

Columns 56-87 contain the observational comments.  These comments will be
printed above each prediction with the name or after the first line of each
prediction when "one-line" output is specified (unless the "N" flag is set).

The quicksat.mag file may have the following comments:
1. date: per nn (dec) - the tumble period in seconds (was decreasing)
3. var n - the object is sometimes fainter than its maximum brightness
           by the specified value (in magnitudes).
4. fl nn - the object sometimes "flashes" and increases brightness
           by the specified amount.
5. fl to nnn - the object has be observed to "flash" up to the given
               magnitude.



        Description of the Orbital Elements File(s)


An orbital elements input file must be in the form of NORAD two-line
elements.  Each may be preceded by the satellite name.  Any line that does
not have a "1" or "2" in column 1 and a blank in column 2 will be ignored.

Examples of two-line elements:

Alouette 1
1 00424U 62B-A  1 90192.70736421  .00000170  00000-0  19423-3 0  3322
2 00424  80.4633 261.8991 0022426 207.0003 152.9977 13.67365462386044
ATS 3
1 03029U 67111  A 90194.54223643 -.00000074  00000-0  99999-4 0  3953
2 03029  13.2438  21.0153 0013818 204.7992 155.1757  1.00272749 83052
Cosmos 398
1 04966U 71 16  A 90200.49713217  .00042980  17752-4  27181-3 0  9862
2 04966  51.5262 157.4892 2249896 208.4414 137.3099 11.10705110595285

The name field is read, but is only used when no entry appears in the
intrinsic magnitudes file.

Note that only 14 characters of a name field will be remembered.  This
means that there is a chance that an object and its rocket body may
have the "same" name if the first 14 characters are the same.

Note:  There is no attempt to check the "check-digit" value.

Note:  The drag term which appears after the epoch is used.  The change in
the drag term value is not used.  The Bstar term is not used.

Note:  The ATS object is discarded because its mean motion is less than 4.

Note:  If carriage return characters are not present at the end of each line,
the program ADDCR may be used to add them.



        Description of the Prediction Output


The first line is an "echo" of some of the input values from
the control file:

  30.334  97.760  520.   5105 Crestway Dr.        2000  6.5 15 F F T T T

The latitude, longitude, height, and site name are listed.  The epoch
of RA and Dec is given.  The magnitude cut-off and altitude cut-off
are given.  Five true/false flags are given.


The next line gives the date and time zone:

***  1990 July 26  Thu evening  *** Times are PM CDT  ***  2116  558

For the prediction date of July 26, the evening predictions are for
Thursday.  The predictions times are PM for the time zone CDT.  The
value 2116 is the local time of twilight when the sun is 10 degrees below
the horizon.  The value 558 is the local time of morning twilight when
the sun is 10 degrees below the horizon.


--- The following describes the "A" two-line output format information ---

The next line gives the titles for each data line:

 H  M  S Tim Al Azi C Dir  Mag Dys F  Hgt Shd  Rng  EW Phs  R A   Dec

Each of these fields will be discussed below.


The object header line is given before the predictions for each object:

20625 Cosmos 2082 Rk 10.4 3.9      23   2.0 

The NORAD catalog number is given.  The name is given.  The three size
values, and the RCS value are given if they are available.  The class
value is given.  The observed intrinsic magnitude is given (if available).
Finally, the comments field from the intrinsic magnitudes file is given.

Each set of predictions has the following form:

 H  M  S Tim Al Azi C Dir  Mag Dys F  Hgt Shd  Rng  EW Phs  R A   Dec
 9 41 54  16 36 261    66  4.0  31 4  536 493  830 0.9 115 1251  10.7
 9 43 22  16 41 297 C  92  3.9  31 4  536 499  759 1.0 123 1234  38.7
 9 44 49  16 34 331   117  4.3  31 4  537 505  856 1.0 124 1140  64.8

The time is UT unless a time zone was specified in the input file.
In the current example, -5 was given to convert UT to CDT.

The Tim value is the estimated uncertainty in the time of prediction
(in seconds).  So, 18 seconds is a "likely" error in this prediction.
If the time error is less than or equal to 3 seconds, then the field
is left blank.

The Al value is the altitude of the prediction point.
The Azi value is the azimuth of the prediction point.
The letter C after the azimuth indicates that this is the point of
culmination.  The absence of the C would indicate that this is not a
culmination prediction.

The Dir value is the direction that the satellite is traveling.  A value
of 0 means traveling "up".  A value of 90 means "right".  A value of 180
means "down".  A value of 270 means "left".  In the given example, the
satellite travels right and a little up from the southwest until the
culmination point is reached.  Then it travels right and a little down
as it moves into the northwest.

The Mag value is the predicted maximum magnitude if an observed intrinsic
magnitude was avaliable.  This does not mean that the satellite cannot be
brighter or fainter than this magnitude.  The satellite can be brighter
if it reflects the sun better than expected at this phase angle.  It can
be fainter than expected if it reflects the sun worse than expected at this
phase angle or if it is a non-spherical object and its particular orientation
is unfavorable on this pass.  Since the comment "var 2.5" appears, then it
is likely that the object can change in brightness from this "maximum
predicted magnitude" to a brightness that is 2.5 magnitudes fainter.  Often
such a variation will take place in less than 2 minutes.  If "var att"
appears, then the object varies very slowly and is usually constant at
some brightness equal to or less than the prediction.  However, the comment
"var att" applies to a large percent of all objects, so I do not normally
explicitly include this as a comment.

If an observed intrinsic magnitude is not available, then the special value
"20" is used for the intrinsic magnitude.  This will normally produce a
predicted magnitude between 18 and 24.  If the observer has an expection of
the intrinsic brightness because of a knowledge of the expected size, then
this "20" magnitude can be transformed as follows: 20 is subtracted and the
expected intrinsic magnitude is added.  For example, if 20.4 appears, but
the observer expects an intrinsic magnitude of 3.5, then 20.4 - 20 + 3.5 =
3.9 and the expected magnitude is 3.9.  If the object is observed to be
about 4.4, then an intrinsic magnitude of 4.0 would be appropriate.

 H  M  S Tim Al Azi C Dir  Mag Dys F  Hgt Shd  Rng  EW Phs  R A   Dec
 9 41 54  18 36 261    66  4.0  31 4  536 493  830  .9 115 1251  10.7
 9 43 22  18 41 297 C  92  3.9  31 4  536 499  759 1.0 123 1234  38.7
 9 44 49  18 34 331   117  4.3  31 4  537 505  856 1.0 124 1140  64.8

The Dys value is the number of days from the epch of the elements to the
prediction date.

The F value is the fraction of a revoltion (in tenths) that the object has
made since its last perigee.  A fractional value of 9, 0, or 1 indicates
that the object is near perigee.  A fractional value of 4, 5, or 6 indicates
that the object is near apogee.  A value of 2 indicates the object is rising
from perigee to apogee.

The Hgt value is the height of the object in miles or kilometers.

The Shd value is the height of the object above the Earth's shadow.

The Rng value is the range of the object.

The EW value is the distance east/west that the orbital plane moves in
one minute.  If this satellite is one minute early, it will be 1.0 degrees
to the east of the predicted position.  If it is one minute late, it will
be 1.0 degrees west of the predicted position.

The Phs value is the sun-object-observer angle.  A value of 0 indicates
full phase, a value of 180 indicates new phase.

The R A value is the right ascension of the prediction.

The Dec value is the declination of the prediction.


---- The following describes the "B" output format information -----

The NORAD catalog number, EW displacement/minute and phase angle are not
displayed.  The object name is given on the first output line only.  If
there is any comment information, it is given only after the first line.

 H  M  S Tim Azi ElC Dir  Mag Dys F  Hgt Shd  Rng  R A  Dec RCS  Name
 9 41 54  18 261 36   67  4.0  31 4  536 493  830 1251 10.7  23 pCosmos 2082 Rk
        var 2.5
 9 43 22  18 297 41C  92  3.9  31 4  536 499  759 1234 38.7
 9 44 49  18 331 34  117  4.3  31 4  537 505  856 1140 64.8

But if the "P" format flag is present, the phase angle is displayed instead
of the range.  If the "N" flag is present, any comments are suppressed.


---- The following describes the "C" output format information -----

The "C" format is the same as the "B" format except that the altitude
precedes the azimuth and the title says "Al Azi".


---- The following describes the "Radio" output format information -----

 H  M  S Tim Al Azi C Dys F  Hgt  Rng
20625 Cosmos 2082 Rk
 9 41 54  16 36 261    31 4  536  830
 9 43 22  16 41 297 C  31 4  536  759
 9 44 49  16 34 331    31 4  537  856
