'\" t .\" Man page by Dale Scheetz .TH seesat5 7 "27 March 96" "Debian Linux" .SH NAME seesat5 \- provides satellite visibility information. .SH DESCRIPTION .LP This man page explains the commands used by seesat5 to produce and control the satellites that will be analysed and the output criterion. These commands are valid for use in SEESAT5.INI, in the command line, and from the seesat5 prompt. .SH SELECTION COMMANDS .TP MAXELEV This selects data where the calculated elevation is less or equal to the entered value. .TS tab (@); l l. @Example: @MAXELEV 70 .TE means that only elevation values of 70 or less will be selected. Only satellites that are at 70 or less degrees in elevation will be selected. .TP MINELEV This selects data where the calculated elevation is greater or equal to the entered value. .TS tab (@); l l. @Example: @MINELEV 15 .TE means that only elevation values of 15 or more will be selected. Only satellites that get to 15 or more degrees in elevation will be selected. .TP MINPHASE This selects data where the calculated phase angle (the angle between the sun and the satellite as seen by the observer), is greater or equal the entered value. .TP MINRANGE and MAXRANGE This selects data where the range of the satellite is within these limits. The number denotes either miles or kilometers depending upon whether you set the MILES or KILOMETERS option. If the satellite never gets between the MINRANGE and MAXRANGE values at your location, then no data is printed for it. The default values for MINRANGE and MAXRANGE is zero and 65535 respectively. .TP SET and RESET These commands are used to set and reset conditions and options. They are as follows : .TS tab (@); l l. @SET SHOWTLE @SET SHOWNORAD @etc. .TE is is useful when you want to see all the data using the ALL command. If you don't reset the selection conditions, the program does not print any lines because the conditions are not satisfied. The values for SHOWTLE, VISMAG, SUNELEVSAT, SUNELEVOBS, MINELEV, MINRANGE, MAXRANGE and SHOWAGE can be reset. .TP SET KILOMETERS | MILES This varient of SET determines whether distances are to be printed in MILES or KILOMETERS. Various people can only visualize distance in one or the other of these units. .TP SHOWAGE When this option is SET, the age (in days) of the element is displayed. This is the age of the element at the time for which the satellite data is printed. Also note that this value is UTC relative. For example, if you do a whole weeks run with the same satellite elements and the satellite is visible every day, then the TleAge value will be 1 day greater in each days printout. .TP SHOWNORAD Show the satellite NORAD number on the printout. .TP SHOWTLE Controles the printing of the Keplerian elements when a LOAD or NEXT is done. When SET, Keplerian elements are printed. When RESET, they are not .TP SUNELEVOBS This selects data where the calculated SUN's elevation at the observers location is less or equal the entered value. .TS tab (@); l l. @Example: @SUNELEV 0 .TE means select data when the sun is at or below the horizon. This will let you filter out satellite's that pass over in daylight. .TP SUNELEVSAT This selects data where the calculated SUN's elevation at the satellite is greater or equal than the entered value. .TS tab (@); l l. @Example: @SUNVAL 0 .TE means that only positive SUN values will be selected. This lets you select data when the sun is shining on the satellite. .TP VISMAG This selects data where the MAGNITUDE is less or equal to the supplied value. .TS tab (@); l l. @Example: @VISMAG 1.0 .TE means the calculated magnitude must be less than or equal to 1.0. This lets you select bright satellites only. .SS GENERAL COMMANDS .TP ALL Toggles between normal mode (predictions below horizon suppressed) and a mode which displays all predictions. .TP APPENDSDF This command requires a file name parameter. This is the same as the OPENSDF command except the file is opened for extend. If the file named does not exist, it will be created. .TP BLOCK This command is used to customize the skyline that you view from. It has the format BLOCK begin-azimuth end-azimuth elevation. The azimuth values are integers between 0 and 359 and the elevation 0 and 90 degrees. You can use this to accurately define your view of the sky. You can enter up to 30 block commands, each one defines a block from a starting azimuth, ending azimuth and an elevation. If a satellite never gets out from behind the blocks you define then its data will not be printed. If at any time (be careful with time steps here), the satellite is visible, then its data is printed and the data where it is behind a block will be printed with a 'b' next to the Az and El values. This lets you know that at that particular time you will not be able to see the satellite although it is above the horizon. .SP The MINELEV command is a more simplified version of BLOCK and only useful in an open field where the "mist line" at the horizon is uniform. BLOCK provides a better solution for "city dwellers" where buildings tend to block only some areas of the sky. .TP CENTER Followed by a time, this command determins the time to center the data run, usually used in conjuction with \fISPAN\fP. .TP Comments If you want to put comments inside your SEESAT5.INI file, just type in a forward slash (/) anywhere you want. When the slash is at the start of a line the entire line is treated as a comment. When it is in the middle of a line, everthing after the slash up to the end of the line is treated as a comment. .TP CMDLINE This command is reserved for use in SEESAT5.INI. When seesat5 encounters this command it executes the commands found on the command line as though they were located in the init file where the cmdline command is located. The main use of this command is to impliment the "go label" command. Typically the init file begins with setup commands that set the viewing location as well as some general filter criterion. Following this with cmdline, followed by as many blocks of instructions as you like, each one beginning with a unique label, allows a runtime choice of which block to execute. .TP DBS and DBS# To select satellites you want to run predictions on. You can maintain the list inside the seesat.bat file, together with comments. You may load the satellite either by name or by Norad Satellite Number. .TS tab (@); l l. @DBS "HST ARRAY" / Last seen 2/3/94, dim, blinks @DBS HST / Last seen with shuttle @DBS "OKEAN 1" / Fast @DBS MIR / Must see soon @DBS 23028 / SEDS 2 @DBS# 16609 / Its MIR again .TE After selecting your favorite satellites, run the prediction using the RUNDBS command. .SP RUNDBS is like RUNTIME but just runs satellites in your database. You can still do RUNALL or RUNTIME any time to run all the satellites loaded with your last OPEN. .SP If you want to select another set of DBS satellites, you can either OPEN a new TLE file (that resets all the DBS entries to false), or more efficiently (if you want to keep the current TLE file open), use the RESET DBS command. .TP EX Execute a batch file of commands. Any SEESAT command may appear in a batch file. Multiple commands per line are allowed, just as if you were entering the command line manually. EX itself may be in a batch file. If encountered, it will close the current batch file and begin executing the specified file. Control will not return to the preceding file. I.e., you can chain batch files but not nest them. .TP EXIT Exit from seesat5. .TP GO or GOTO Requires a label name to go to, and starts processing there. The GOTO command is probably going to be most useful from the command line to let you jump into a particular SEESAT5.INI file section of your choice. Obviously, any commands following the GOTO will not be processed. When you specify a GOTO command, the program begins searching the SEESAT5.INI file from the beginning and looks for the LABEL line. If one is not found, the message END OF BATCH FILE is displayed and the program goes into keyboard command mode. If you have duplicate labels, the first one will be processed. No checking is done to prevent you from making the program loop continously, so be careful. Also, if you use EX'ed files, the GOTO will only goto labels in the current file that is open. .TP HELP Displays a help screen. .TP HEIGHT Number, specifies, in kilometers, the height of the viewing location. Errors incurred from incorrect values for height have little propogation into the satellite location prediction. As a result, if you don't know your height, it may safely be left 0. .TP INDEX Lists the satellites in the currently open file. If there is more than one screenful, it will pause with a "more>" prompt. At this prompt you may either press RETURN to continue the listing, or enter a command (or commands) just as you would at the normal command prompt. In that case, the listing is aborted and your commands are executed. .TP LABEL This command requires a parameter that is a label that you want to GOTO later. The maximum label length is 30 characters and it must be the FIRST command on the line. More commands are allowed after the label name if you want, but I found it more readable to have the command on a single line. .TS tab (@); l l. @Example @LABEL DAILY-RUN .TE Use labels to keep my run parameters for different situations in a single SEESAT5.INI file and select which ones to process using the GOTO command. .TP LAT The number, in degrees, specifies the latitude of the viewing location. Southern latitudes are declaired with a negative number. Precision in this location is critical. A .14 degree error in location, approximately 10 miles will cause a 1 degree error in the satellite position. .TP LENGTH Sets maximum number of characters the OPEN command will consider significant in the satellite name when building the index. The LENGTH command must therefore be issued before OPEN, to have any effect. Any number from 1 - 22 is allowed. Default is 22, and may be left alone unless you're using a file such as Molczan's N2L series. In that case, you'll want to reduce LENGTH to 15 to prevent SEESAT from using the extra data as part of the satellite name. LENGTH is set to 22 if you enter a number larger than 22. .TP LINEFEED This command as added for predictions done on a machine where a typical run takes hours. Starting the run with the output redirected to the printer serves two purposes: .TS tab (@); l l. 1.@to print out the data, and 2.@to serve as an alarm. .TE How does this serve as an alarm? With a dot matrix printer the machine can be left to run. While other work gets done the machine chuggs along. Eventually, the program finds a satellite that can be seen. When the printer starts clacking away after the long silence you know that there is new data available. So that you can come to the printer and tear off the new data without interfering with potential new printing this command prints a selected number of linefeeds after the satellite listing. .TP LOAD Loads the named satellite from the file you opened with the OPEN command. If the name has spaces, begin the name with quotes. .TP LOAD# This is just like the original LOAD command except you must supply the Norad Satellite number. This is most usefull when you have TLE files from different sources and the satellite names are not consistent. .TP LON The number, in degrees, specifies the longitude of the viewing location. Western longitudes are specified with a negative number. As with latitude a relatively small error of .14 degrees will cause a 1 degree error in the satellite location. .TP MAG For entering the absolute magnitude of a satellite. It will be adjusted for range and illumination angle to generate the "mag" value in the prediction table. Absolute magnitude is its magnitude at 1000 km and 50% illuminated (i.e., 90 degree phase angle). .SP Absolute magnitude input can be automatic during loading of the elements from the file. If the first line of the element set (the satellite name line) is longer than 32 characters, SEESAT assumes it's a Molczan format line, and reads the magnitude. You can use the MAG command to override the value if necessary. .TP MAGBIAS Bias to be applied to SEESAT's computed magnitude before display. A negative sign is allowed. The default is zero. .SP If your absolute magnitudes assume a different range and/or illumination than 1000 km and 50%, the MAGBIAS command will bring your scale into coincidence with SEESAT's. If r and k are your assumed standard conditions (in km and percent, respectively), set MAGBIAS to: .TS tab (@); l l. @2.5 * log10 ((1000/r)^2 * k/50) .TE For example, if your absolute magnitude is for 1000 km range and 100% illuminated, enter: .TS tab (@); l l. @MAGBIAS .8 .TE .TP MERIDIAN The satellite longitudes in the prediction table may be computed with respect to either Greenwich or your local meridian. MERIDIAN toggles this mode, and informs you of the current mode. Default is Greenwich. .TP MOON Print the azimuth & elevation of the moon at the given time. Percentage of illumination is also given. .TP NEXT Loads the next satellite from the current open element file. .TP NOMINAL / ACTUAL These commands adjust the epoch and RAAN of the currently loaded elements for the difference between the nominal and actual launch times. They are useful for correcting a prelaunch element set. .TS tab (@); l l. @EXAMPLE: @NOMINAL 19 1851 ACTUAL 1918 .TE tells SEESAT that the currently loaded elements assume a launch on the 19th at 1851, but the launch actually occurred at 1918. .SP You can't use NOMINAL or ACTUAL by itself! If you use one, you must also use the other or you'll get crazy results. The order of the commands does not matter, and they don't have to be on the same line. Just be sure that both commands have been given before starting a prediction run. .SP The entered values are remembered. So you may, for example, use NOMINAL just once, then experiment with different ACTUAL values. .SP Loading an element set (even reloading the same one) disables the effect of NOMINAL and ACTUAL. Their values are still remembered, however, so you may re-enable the adjustment by giving one or both commands. .SP The NOMINAL and ACTUAL arguments may be for any time zone, as seesat5 cares only about their time difference. .TP NULL This command is useful if you want to specify year, month day and time for the start/stop/span commands but don't want to do the RUN command automatically. It can save specifying repeated information on every line of your parameters. .TS tab (@); l l. @Example : @open my.tle span 720 null @start 1993 oct 01 1900 runall @start 1993 oct 02 1900 runall @exit .TE .TP OFFSET