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/--------------------------------------------------------------\ | | | | | StarWorks | | | | Planetarium Simulator | | | | User Guide | | | | Copyright 1993 | | | | | | | | | | Sci-Vision | | PO Box 941532 | | Suite 269 | | Dallas, Texas | | 75094-1532 | | | | | | | | Document Revision 2.01 | | | | Printed December 13, 1993 6:45 PM | | | | | | | \--------------------------------------------------------------/ Table of Contents Introduction 1 Horizon Display Description 2 Zenith Display Description 3 Sky Map Display Description 4 Orbital (zenith) Display Description 5 Orbital (ecliptic) Display Description 6 Jupiter's Moons Display Description 7 Planet Size Display 8 Planet Position Display 8 Planet Distance Display 8 Planet Rise Times Display 9 Pick Mode 9 Find Mode 11 Menu Screen Descriptions 11 Main Menu 12 Setup Menus 13 Time Setup Menu 14 Star Setup Menu 14 Planet Setup Menu 15 Location Setup Menu 16 Trails Setup Selection 16 View Direction Setup Selection 16 Zenith View Angle Setup Menu 17 Sky Window Setup Menu 17 Save Setup Selection 17 Restore Setup Selection 18 Files used by StarWorks 18 STARFILE 18 COMETFIL 19 STARWORK.MNU 19 Technical Notes 19 Program Call 20 STARWORKS Environment Variable 21 GMT / Local Time /Daylight Savings Time 21 Phase 22 Altitude and Azimuth 22 AU Astronomical Units 23 Formulas used by the program 23 Development System 23 Program Accuracy 23 Astronomical Experiments 23 Caveats 25 Terms of License 26 Copyright Notice 26 Introduction StarWorks is a program which provides astronomical simulations the same way as seen in a planetarium. StarWorks will show the past, present and future skies as viewed from anywhere on Earth. The program will display the position (with real time updating) of the planets and comets in orbit around our Sun as well as calculate specific data about celestial bodies. StarWorks will even display the moons of Jupiter as they orbit the planet. Program options allow the user to select the date and time to view, the direction of view, the viewer's latitude and longitude on Earth, and much more. Using the display updating parameters StarWorks can display a complete day's movement of the heavens, or demonstrate the retrograde motion of the planets. StarWorks will run on any DOS based system (DOS version 2.0 or greater) which has SuperVGA, VGA, EGA, CGA or Hercules graphics and a hard disk. Note that although the program will run in CGA mode, the display quality is poor because of the lack of resolu- tion and colors. StarWorks will run with or without a math co-processor, however, it can be very slow without one because of the intense floating point arithmetic involved. If the version number displayed on the first screen ends with '(Limited),' this version of StarWorks is being distributed as a Limited Demonstration version. Its only limitations are that it will work for a limited date range and that it includes fewer stars/objects in the data base. The Full Function version will work between the years 1700 and 2500. The full function version also includes over 11,000 stars and messier objects. The Full Function version can be requested by sending a support donation using the form at the end of this document. Horizon Display Description The Horizon display attempts to show the sky as seen from Earth when looking in a specified direction at a specific time of day. The left side of the display is what would be seen over your left shoulder as is the right side over your right shoulder. The top of the display shows what you would see directly over your head. Because of the transformation from 3-dimensions to 2-dimensions, the distortion increases as you approach the edges of the arc. Another way to think of what the display is representing is image you are sitting in the middle of the planetarium. You see in front of you half of the dome. The difference is that at the planetarium your field of view would not be large enough to see the complete half dome all at one time. With the program the complete half dome is compressed onto the flat screen. The Moon is drawn in its approximate phase with the New Moon represented with an empty circle. The drawing of the phase of the Moon is rounded to the nearest quarter (New, First Quarter, Half, Third Quarter, Full, etc.). By using menu selections you can control the brightness/size of the stars/objects, direction of view, select Real Time display or a User Defined time, change the update rate of the display and much more. Note that the time and date displayed at the top of the screen represent Local Time and assume that the system clock is set to daylight savings time when applicable (see technical notes for more details on daylight savings time). When 'Leave Trails' is turned on the time/date displayed on the left is the start time and the time/date on the right is the current time. CONTROL KEYS for this display are: p : Pause the updating of this display and put the display in PICK mode (See Pick Mode) Escape: Exit Pause/Pick Mode. Enter : Pick Star (while in Pick Mode). Any key press releases pick. t : Toggles whether objects leave a trail as they move s : Toggles between Local Time and Sidereal Time o : Outline the Constellations (In Pick Mode) l : Dump current screen to an IBM compatible printer (Best results are obtained in EGA Mode) left/right arrows: scroll display view to the left/right. (changes view direction) Zenith Display Description The Zenith display attempts to show the sky as seen from Earth when looking directly over head at a given time of day from a specified location on Earth. The top of the displayed circle represents the compass direction of North, the bottom of the screen is South, Right is to the West and the left side of the circle is toward the East horizon. Keep in mind that distortion increases as you approach the edges of the circle, especially for wide View Angles. The Zenith View Angle specifies the lowest altitude an object may be at and still be plotted on the display. For example, if Zero is entered, then all object whose altitude is currently above the horizon will be plotted. If 89 is entered, only objects whose current altitude is greater than 89 degrees will be display. Thus only objects within one degree of vertical to be displayed. The Moon is drawn in its approximate phase with the New Moon represented with an empty circle. The drawing of the phase of the Moon is rounded to the nearest quarter (New, First Quarter, Half, Third Quarter, Full, etc.). By using menu selections you can control the brightness/size of the stars, direction of view, select Real Time display or a User defined time, change the update rate of the display and much more. Note that the time and date displayed at the top of the screen represent Local Time and assume that the system clock is set to daylight savings time when applicable (see technical notes for more details on daylight savings time). When 'Leave Trails' is turned on the time/date displayed on the left is the start time and the time/date on the right is the current time. CONTROL KEYS for this display are: p : Pause the updating of this display and put the display in PICK mode (See Pick Mode) Escape : Exit Pause/Pick Mode. Enter : Pick Star while in Pick Mode. Any key press releases pick. t : Toggles whether objects leave a trail as they move s : Toggles between Local Time and Sidereal Time o : Outline the Constellations (In Pick Mode) l : Dump current screen to an IBM compatible printer (Best results are obtained in EGA Mode) Sky Map Display Description This display is used to create a Sky Map located at given Right Ascension/ Declination coordinates. All objects within the boundaries of the window are displayed. This display is useful for 'zooming' in on a region of the sky the same way a more telescope would be able to zoom in on a particular area of the sky. The initial center and width of the display are determined from the values entered into the menu. The width is interpreted as the amount of right ascension covered from the left side of the window to the right. The amount of declination covered in the display is calculated automatically to give the correct scaling. The scaling factor also takes into account the aspect ratio of the display device. While viewing the sky map, the center of the display can be shifted in Right Ascension using the left/ right arrow keys and can be shifted in Declination using the up/ down arrow keys. The window width can also be increased or decreased using the '-' and '+' keys. Note that star brightness/size is controlled as described for the Horizon and Zenith displays and the time/date are displayed as described for the Horizon and Zenith displays. CONTROL KEYS for this display are: Left / Right Arrows : Pan Display Window Left / Right Up / Down Arrows : Pan Display Window Up / Down + : Zooms in on the Center of the Window - : Zooms out from Center of the Window m : Toggle Between Current View and Full-Sky View p : Pause the Updating of the Display and Enter Pick mode. Enter : Select Object at Cursor (Pick Mode) t : Toggles whether objects leave a trail as they move s : Toggles between Local Time and Sidereal Time f : Finds object matching user entered name (Object Find) o : Outline the Constellations (In Pick Mode) l : Print Current Display to Print Device ESC : Exit the Display Orbital (zenith) Display Description This attempts to show the position of the planets and comets as they orbit the Sun. The view is from above the plane of the solar system with planets moving counter clockwise around the Sun. By using the control keys you can zoom in toward the Sun or back away from it. The 't' key toggles whether the planets leave a trail as they move. The control keys will also allow you to freeze motion. Note that the time and date displayed at the top of the screen represents Local Time and assumes system clock is set to day- light savings time when applicable (see technical notes for more details on daylight savings time). When 'Leave Trails' is turned on the time/date displayed on the left is the start time and the time/date on the right is the current time. CONTROL KEYS for this display are: p : Pause the updating of this display and enter Pick Mode Enter : Select Object at Cursor (Pick Mode) t : Toggles whether planets leave a trail as they move + : Zooms in on the Sun - : Zooms out from the Sun * : Zooms out from the Sun (x10) r : Restore Default Zoom value l : Dump current screen to an IBM compatible printer (Best results are obtained in EGA Mode) Orbital (ecliptic) Display Description The Ecliptic Orbital Display attempts to show the position of the planets and comets as they orbit the Sun. The perspective of this view is the ecliptic plane of the solar system. It is viewed edge-on as seen from a position at the bottom of the screen on the Orbital (zenith) Display. By using the control keys you can zoom in toward the Sun or back away from it. The 't' key toggles whether the planets leave a trail as they move. The control keys will also allow you to freeze the motion of the planets. As in all displays, the Escape key exits from the display. Note that the time and date displayed at the top of the screen represents Local Time and assumes system clock is set to daylight savings time when applicable (see technical notes for more de- tails on daylight savings time). When 'Leave Trails' is turned on the time/date displayed on the left is the start time and the time/date on the right is the current time. CONTROL KEYS for this display are: p : Pause the updating of this display t : Toggles whether planets leave a trail as they move + : Zooms in on the Sun - : Zooms out from the Sun * : Zooms out from the Sun (x10) r : Restore Default Zoom value l : Dump current screen to an IBM compatible printer (Best results are obtained in EGA Mode) Jupiter's Moons Display Description The Jupiter Moon Display shows the position of the four major moons of Jupiter as they orbit the planet. The view perspective begins as you would see Jupiter and its moons when looking through a telescope. Using the UP/DOWN arrow keys the perspec- tive can be changed. Pressing the UP arrow key moves the perspec- tive of the observer up from the plane of the moon's orbits toward the North Pole of Jupiter. Pressing the Down arrow key moves the observers perspective back down to the plane of moon's orbit. In the upper left corner of the screen is displayed the current simulated width of the screen in Million Kilometers. In the upper right corner of the screen is the observers angle above the plane of the moon's orbit. When the Tilt is zero, the display simulates the view an observer would have from earth. As the Tilt is increased, the view changes to the view an observer would have looking down on Jupiter from its North Pole. By using the control keys you can zoom in toward Jupiter or back away from it. The 't' key toggles whether the moons leave a trail as they move. As in all displays, the Escape key exits from the display. Note that the time and date displayed at the top of the screen represents Local Time and assumes system clock is set to daylight savings time when applicable (see technical notes for more de- tails on daylight savings time). When 'Leave Trails' is turned on the time/date displayed on the left is the start time and the time/date on the right is the current time. CONTROL KEYS for this display are: t : Toggles whether moons leave a trail as they move o : Toggles display of the orbital paths of the moons + : Zooms in on Jupiter - : Zooms out from Jupiter Up : Move view perspective up towards Jupiter's North Pole Down : Move view perspective down towards the plane of the moon's orbit. * : Zooms out from Jupiter (x2) r : Restore Default Zoom value l : Dump current screen to an IBM compatible printer (Best results are obtained in EGA Mode) Planet Size Display The Size display allows the user to visualize the difference in size between any two planets, the Sun, Moon and other bodies. The display draws the two bodies to relative scaled size and labels them at the bottom of the display. Above each of the bodies is their diameter in Miles. The figures which appear between the two bodies show the ratio of the size of the larger to the smaller one. Note: If the ratio of size is written in Red, then the size dif- ference was beyond the resolution of the screen. Pressing the Esc key will exit the display. * Refer to Update Mode description of the Setup Time Menu. Planet Position Display This screen provides numerical information about the planets, Sun and Moon's position as viewed from Earth. The Right Ascension and Declination for each body are given along with its Altitude and Azimuth. Each time a key is pressed (excluding the Escape key and the 'A' key) or the Left mouse button is pressed, the display time is updated according to the Update Mode and the fields are recalcu- lated and redisplayed. Pressing the 'A' key or the Right Mouse button will cause the display to continuously update until another key is pressed. Pressing the Esc key or pressing the mouse Left and Right button will exit the display. * Refer to Update Mode description of the Setup Time Menu. Planet Distance Display This screen provides numerical information about the distance of the planets from the Earth and Sun. It displays the distance from the Earth to each of the Planets and the distance from each of the Planets to the Sun. The dis- tance is measured in Astronomical Units (AUs) and in Millions of miles. AUs are equal to 149.6 Million Kilometers or 92.96 Million Miles. Each time a key is pressed (excluding the Escape key and the 'A' key) or the Left mouse button is pressed, the display time is updated according to the Update Mode and the fields are recalcu- lated and redisplayed. Pressing the 'A' key or the Right Mouse button will cause the display to continuously update until another key is pressed. Pressing the Esc key or pressing the mouse Left and Right button will exit the display. * Refer to Update Mode description of the Setup Time Menu. Planet Rise Times Display This screen provides numerical information about the rise and set times of the planets, Moon and Sun. This display shows the rise and set time of each of the planets, the Sun and the Moon. The Total Rise column gives the amount of time the body is above the horizon. The Phase and Apparent Magnitude of each of the bodies are also listed. Each time a key is pressed (excluding the Escape key and the 'A' key) or the Left mouse button is pressed, the display time is updated according to the Update Mode and the fields are recalcu- lated and redisplayed. Pressing the 'A' key or the Right Mouse button will cause the display to continuously update until another key is pressed. Pressing the Esc key or pressing the mouse Left and Right button will exit the display. * Refer to Update Mode description of the Setup Time Menu. Pick Mode When in the HORIZON, ZENITH, SKY MAP or ORBITAL (zenith) display modes, the user has the option of picking an object on the dis- play to identify it. The object to be identified is selected using a graphics cursor. If the cursor is positioned within the capture range of an object, and the Retrn key is pressed, it will lock on to that object and display information about it. If the cursor is not within the capture range of an object, the Alti- tude/Azimuth and Right Ascension/Declination of the location selected is displayed. During Pick Mode, the user has the option of outlining the con- stellations (Asterisms) by pressing the 'o' key. These outlines can be left on during the 'Picking' process. To turn off the outlines simply press the 'o' key again. HOW TO USE THIS FEATURE: While in a display which supports Pick Mode, press the 'p' key to enter Pick mode. After all objects on the display have been updated to reflect the displayed time, Pick Mode will be entered. Move the cursor around the screen by pressing the arrow keys. For finer cursor movement press the SHIFT or NUM LOCK key along with an arrow key. When the cursor is pointing at the desired object, press the Retrn key to select it. If the cursor is within the capture range of an object the cursor will first be repositioned to point at the object. A pop up window will then appear which will provide details about the object. Depending on display type being viewed, the following information may be included: ? Altitude and Azimuth (See Technical notes for definition). ? Right Ascension and Declination. ? Distance from Sun and Earth ? Phase of the object. ? Apparent Magnitude of the object. ? Constellation the object is part of. ? Meaning of Constellation name. Ie. Orion, "THE HUNTER" ? Name of the object. ? Spectral Type of the object. ? Object Type (Planet,Comet,Star,Double Star,Nebula,etc.). A Microsoft Compatible Mouse can also be used in pick mode. While viewing one of the displays that supports pick mode, press- ing the left mouse button will enter pick mode, just as the 'p' key does. Once in pick mode, the mouse can be used to position the pointer the same way that the arrow keys do. When the pointer has been positioned to the desired object, the left button of the mouse can be used to select the object just as the Retrn key will. Pressing the right button of the mouse while in picked mode, with nothing currently selected, will exit pick mode the same way the Escape key will. Pressing the center mouse button in pick mode will toggle con- stellation drawing just as the 'o' key does. Pressing the Left and Right mouse buttons together, while not in pick mode, will exit the display and return to the main menu. Find Mode Find Mode will allow the user to select an object by name. If a matching name is found among the planets, comets, stars or other objects, the matching object will be displayed. Pick Mode will automatically be entered with the cursor preset to point at the selected object. This feature is available on the Horizon, Zenith and Sky Map displays. To use this feature, select the Horizon, Zenith or Sky Map dis- play from the main menu. A press of the 'f' key will display a pop-up menu. The name of the object to be located is entered at the cursor. The entered name may contain letters, numbers and wild-cards (discussed next). Pressing return accepts the input name and the search begins. As objects are being search, matches to the input name are display whenever found. The user is asked whether this is the object they were looking for. If not, the search continues. If the object found is correct, the display boundaries will be adjusted if necessary to display the object. At this point, Pick Mode will automatically be entered and the cursor will appear pointing at the selected object. Pick mode will work the same as previously described at this point. On the Sky Map display, the display can always be adjusted to display the matched object. On the Horizon and Zenith displays, the display direction (or view angle) will only be adjusted if the object is above the horizon. Wild-cards are the '*' and the '?' characters. They can be placed anywhere in the search string when the exact name is not known. The '*' will match any amount of characters and the '?' will match any single character. Say we are looking for the star Betelgeuse in Orion but you're not quite sure how to spell it. Just enter bet*. Any object with its name starting with 'bet' followed by any other charac- ters will be a match. Another example is, you're looking for messier object M40-something. Enter the search string of m4?. This will match any three character string with the first two characters being m4. Menu Screen Descriptions This section describes the purpose and function of each of the menu screens. The overall layout consists of a main screen which has selections for each different displays on the upper half. Along the bottom of the menu are the sub-menu selections. Each of these allows the default parameters of StarWorks to be 'Tuned' to fit your specific application. The Color of the StarWorks menu screens may be altered to suit your individual taste. The default screen color starts out as Blue but can be changed per execution by using the '-C' program call option (see program call options for more details). The default of Blue can also be changed. Anytime the 'Save Setup' selection is made, the screen color currently in use becomes the new default color. Remember, the default screen color is used anytime the '-C' call option is not present. Main Menu The main menu is basically made up of two parts. One part allows the user to select a display to view. These graphic and table displays are listed below. Refer to description of each display type in the previous sections. To select one of the following display types, simply press the corresponding key to the display you wish to view. Provided that all user entered parameters from the setup menus are valid, a display will appear. If a mouse is active, a block cursor will appear within the Display Selection boundaries. Position- ing the block cursor near the display to be selected and then press the left button. This will have the same effect and pressing the selection key itself. Key Display See Page ___ _______ ________ 1 Horizon Display pg. 2 2 Zenith Display pg. 3 3 Sky Map Display pg. 4 4 Solar Orbit Display pg. 5 5 Jupiter's Moons Display pg. 7 6 Relative Sizes Display pg. 8 7 Distance Data pg. 8 8 Rise/Set Data pg. 9 9 Position Data pg. 8 I Information for Display Controls Esc Exit Program Setup Menus The second part of the main menu is the Setup Sub- menu selections. These are found on the bottom two lines of the main menu. Using these setup menus, StarWorks can be configured simulate different events. To activate one of the setup menus, use the tab or arrow keys to cause the desired sub-menu box to blink. Pressing return will then cause a pop up menu to appear where new parameters can be entered. If a mouse is installed, pressing the right button will simulate the TAB key being pressed. Pressing the left/right button combination will simulate the RETURN key being pressed. To change the values in a setup menu, begin by using the Tab key to position the cursor to the field to be changed. Enter the new value and press the Return key. The back space key may be used during value entry. When all fields are changed as desired, the Esc key is pressed to return to the Main Menu. If a mouse is installed, the left and right buttons can be used instead of the Tab and Esc keys respec- tively. If a field in the setup menu was being entered and the Return key has not yet been pressed, the Esc key will treat the field as though the Return key had been pressed before exiting back to the main menu. The 'Trails' and 'View Direction' setup selections do not have sub-menus. Instead they toggle/advance the current value with each press of the Return key. Time Setup Menu This menu is used to define the time for which the display is drawn and to define how much time each consecutive display is advanced. UPDATE MODE- If System Clock (0) mode is selected then the system's clock is used to derive the time for each consecutive display and the value of Update Rate is ignored. The value of User Defined time is also ignored. Values other than 'System Clock' use the User De- fined Time described below. Incrementing each consecutive display is done by adding the Update Rate to the displayed time according to the display mode. A Sidereal Day is one revolution of the Earth with reference to the stars ( instead of the Sun). It is approximately equal to 23 hours and 56 minutes. A Lunar Day is one revolution of the Earth with reference to the Moon (instead of the Sun). It is approximately equal to 1 day and 50 minutes. UPDATE RATE defines how much time is added to each consecutive display. It is used whenever the 'System Clock' Update Mode is NOT selected. See Update Mode definition. MONTH, DAY, YEAR, HOUR, MIN, SEC are used to set the User Defined Time. See Update Mode. * NOTE *: User defined time is specified in Local Time including Daylight Savings Time when applicable. Star Setup Menu This menu is used to configure how stars will be displayed when viewing the Horizon, Zenith and Sky Map displays. Stars can be turned on or off and the viewable magnitude limits can be adjusted. DISPLAY STARS selects whether or not stars are displayed on the Horizon, Zenith and Sky Map dis- plays (Note: our Sun is not considered to be in the set of stars but is treated more like a planet) ENLARGE STARS, If set, brighter stars will be drawn larger than dimmer stars and comets will be drawn as a cross. Although this selection creates stars which are not true to size, it may be helpful for Non-EGA/VGA monitors which can not show different star intensities. It may also be useful for creating more readable printouts on the print device. The CUTOFF values used for determining intensities are the same values used to determine plotting size. FIRST CUTOFF, Stars with magnitudes between minus infinity and the First Cutoff are displayed in a high intensity white or largest size. SECOND CUTOFF, stars with magnitudes between the first cutoff and the second cutoff are displayed in a medium intensity white or a medium size. THIRD CUTOFF, stars with magnitudes between the second cutoff and the third cutoff are displayed in a low intensity white or a small size. Stars with magnitudes dimmer than the third cutoff are not displayed at all. For SuperVGA mode, the above is basically still true. The exception is that star intensities are displayed in 55 different shades of white instead of only 3. The intensity of each displayed star/object is set in accordance with its brightness as propor- tional to its magnitude. For brightness, only the value of cutoff3 is important. The brightest star shade is assigned to the magnitude of the brightest star loaded from the star file. The dimmest shade is assigned to stars with magnitudes equal to the value of cutoff3. The remaining shades are assigned based on the star's magnitude in respect to this range. For enlarging stars/objects, all three cutoff values work as they do in EGA/VGA. These cutoff values allow the user to limit the stars displayed, to the stars that can actually be seen due to the amount of ambient city lights where they are located. Planet Setup Menu This menu is used to select which bodies will appear on the displays and which bodies will be listed in the tables. Select 'Yes' to enable the display of each body and 'No' to disable it. Location Setup Menu This menu allows the user to define where they are located on the planet Earth. This information is not used in the Orbital or sky map Displays. Nor is it used on the Planet Distances display. LONGITUDE is the observer's longitude on Earth. This value is used in the Horizon and Zenith Dis- plays and Positions Table. West of the Prime Merid- ian is positive and East is negative. Example: Mpls, Mn. is approximately +90 Columbus, Ohio is approx. +80 LATITUDE is the observer's latitude on Earth. North of the Equator is positive and South is negative. Example: Mpls, Mn. is approximately +45 Columbus, Ohio is approx. +40 TIME ZONE describes the difference between Greenwich time and local time. Example : Central Time is a +6. Eastern Time is a +5. New Zealand is in -12. Trails Setup Selection LEAVE TRAIL selects whether the bodies on the graph- ical displays leave a trail behind them as they move. This is useful for examining the paths they are following. View Direction Setup Selection VIEW DIRECTION is used to select which direction you are looking when using the Horizon Display. Direc- tion is the same as it's measured using a magnetic compass. The full 360 degree circle is broken into eight directions; North, North East, East, South East, South, South West, West, and North West. Zenith View Angle Setup Menu ZENITH VIEW ANGLE defines the lowest Altitude that an object can currently be at, and still appear on the Zenith display. The smaller the value, the narrower the imaginary cone of view above you will be. A value of zero provides a fish eye view of the looking up, including the whole horizon around the edge of the circle. Sky Map Window Setup Menu The values entered here define the location about which the Sky Map will be centered and how much Right Ascension will be included between the left and the right edges of the window. CENTER (RA) defines the value of right ascension that the sky map display will begin at. CENTER (DEC) defines the value of the declination that the sky map display will begin at. WIDTH (RA) defines the amount of right ascension that will be displayed between the left and right edge of the sky map display. Save Setup Selection SAVE MENU SETUP will save the current state of the menu selections and definitions. NOTE: The saved menu configuration is read in at program startup from StarWork.MNU. This will enable you to set items such as your longitude, latitude and time zone, then have them come up as the default every time you run the program. Example, Go through all the menus setting up the parameters the way they apply to your specific situation. Then select the Save Menu Setup option by moving the flashing-option cursor to the Save Menu Setup box followed by pressing the Retrn key. A pop up window will appear confirming the save. From now on the menus will be setup this way every time you start the program. You may also choose to save other menu configura- tions under different names. When restoring a menu setup, you may enter the name of any of the saved configurations. Restore Setup Selection RESTORE MENU SETUP will reread the StarWork.MNU file and reload the default menu setup parameters that the program starts up with. When restoring a menu setup, you may also enter the name of any of the saved configurations. The de- fault file name will be the name of the last setup file accessed. Files used by StarWorks This section describes the files used by StarWorks. It explains their usage and where applicable, their format. STARFILE This file contains the star data used by StarWorks. StarWorks will read as many of the stars from STARFILE as will fit into the available memory on your system. The chime tone will sound if the number of stars read in was limited due to lack of available memory. This file is in binary format and contains the following information, which can be seen when an object is PICKED in Pick Mode. ? Right Ascension of the object. ? Declination of the object. ? Magnitude (apparent) of the object. ? Which constellation the object belongs to. ? The name of the object. ? Spectral Type of the object. ? Object Type, Ie. - Star, Double Star, Nebula, etc. COMETFIL This file contains the orbital elements for periodic comets. The file has the format field 1: Comet Type (p-periodic , n-nonperiodic *-comment line) **** for Periodic Comets **** field 2: Perihelion Epoch field 3: Perihelion longitude (degrees) field 4: Longitude of ascending node (degrees) field 5: Period (years) field 6: Semi-major axis of orbit (AU) field 7: Eccentricity ( only values < 0.98 ) field 8: Inclination of orbit (degrees) field 9: Name of comet (no spaces, less than 20 chars) ***** for Non-Period (Parabolic) Comets **** field 2: Perihelion Epoch data field 3: Perihelion Distance (AU) field 4: Argument of Perihelion (degrees) field 5: Longitude of ascending node (degrees) field 6: Inclination (degrees) field 7: Name of comet (no spaces, less than 20 chars) Any line with an asterisk (*) in the first column is treated as a comment line. *NOTE: ALL fields must be filled in for the particu- lar comet type. Currently, minimal verification is performed on the data. STARWORK.MNU This is the file used to save the current setup of the menus. Refer to its definition under the Save Setup section of the Setup-Menus description. Every time StarWorks is started, this file is read (if it exists) and the menu default parameters are loaded from it. This file is also read to Restore the default menu parameters on the 'Restore Menu' option. Technical Notes Program Call After moving to the directory which contains the StarWorks.exe, starfile. and optional StarWork.MNU files, the program should be called as follows: StarWorks {-options} Where current options are: s -Do not pause during title display. n -Do not correct for Daylight Savings Time. ( For Countries which do not use DST ) d -Use European Daylight Savings Time Dates. A -Use Australian Daylight Savings Time Dates. v -Force VGA display mode. (640x480, 16 colors) V# -Force SuperVGA display mode. 1 - (640x400, 256 colors) 2 - (640x480, 256 colors) 3 - (800x600, 256 colors) 4 - (1024x768, 256 colors) ** NOTE ** (see CAVEATS section for notes on SuperVGA modes) e -Force EGA display mode. (640x350, 16 colors) E -Force EGA MONO display mode. (640x350, 2 colors) c -Force CGA display mode. (320x200, 4 colors, palette 1) m -Force Monochrome display mode. (640x200, 2 colors) h -Force Hercules display mode. (720x348, 2 colors) l# -Limit the stars loaded into the program to those whos magnitude is greater than #. x# -Limit the Maximum number of stars loaded from STARFILE to # C# - Use the color # for menu screens where 1-Blue 2-Green 3-Cyan 4-Red 5-Violet 6-Brown 0-Black M -Do Not invert the Foreground/Background colors on sub-menu screens. P# - Number of passes over the paper when printing ( default is One ) S# - Selects alternative Symbols/Colors for Solar bodies. 0 - (default) original StarWorks colors 1 - swaps colors of Sun and Moon 2 - naked eye visual representation Examples: StarWork -d -C2 { Would use European DST correction and would use Green for the Menu Color } StarWork -v -n { Would turn off DST correction AND force the program to override the detected graphics mode and use VGA graphics display mode instead. *** NOTE ***: OPTIONS ARE CASE SENSITIVE. STARWORKS Environment Variable If there is an environment variable named StarWorks set, the program will use its value as the path to access the files used by the program and you will no longer have to change to your StarWorks directory for the StarWorks program to find its files. As an example, add the line SET StarWorks=C:\StarWorks to the autoexec.bat file (assuming the directory c:\StarWorks contains the StarWorks program and all it's related files). Reboot your system. Now change to any other directory, say the root directory. Execute the StarWorks program (c:\StarWork\StarWork). StarWorks will still be able to find its working files even though you are not in the StarWork directory. GMT Time / Local Time /Daylight Savings Time StarWorks thinks in terms of Greenwich Mean Time, but interfaces with the user in their Local Time. StarWorks uses the value you set in TIME ZONE (see the Location Menu) to make this correction. Your system clock should always be set to the cor- rect local time. This includes daylight savings time if applicable. If daylight savings time is not instituted where you are located or you do not want to set your system's clock in daylight saving time, StarWorks can be called with the 'n' option. This will instruct the program not to make any correc- tions for daylight savings time and will expect the clock to be set to Local Standard time. NOTE: Daylight Savings Time is assumed to begin on the FIRST Sunday in April and end on the LAST Sunday in October (U.S. DST). European DST (see the 'd' program call option) is assumed to begin on the LAST Sunday in March and end on the LAST Sunday in Sep- tember. Australian DST (see the 'A' program call option) is assumed to begin on the last Sunday in October and end on the First Sunday in March. Phase The phase of a body is defined as follows: (using the Moon phases as an example) 0 or 360 degrees is the New Moon. 270 degrees is the first half (Waxing half). 180 degrees is the full Moon. 90 degrees is the last half (Waning half). This applies to all other solar system bodies. Altitude and Azimuth Altitude and Azimuth describe the elevation and compass direction an object is from the observer. Altitude is measured in degrees above the horizon. 0.0 is on the horizon and 90.0 is straight up at zenith. A negative altitude implies that the object is below the horizon. Azimuth is measured in degrees from North. 0.0 is North, 90.0 is East, 180.0 is South and 270.0 is West. AU Astronomical Units Astronomical Units are a measure of length which are roughly equal to the radius of the Earth's orbit around the Sun at its farthest point. 1 AU = 149.6 Million kilometers. Formulas used by the program The formulas used by this program were derived using the book 'Practical astronomy with your calculator' written by Duffet Smith, Peter. Published by Press Syndicate of the University of Cambridge 1979, 1981. Development System This program was written using Turbo-C++ 1.01 on a Unisys IT with an EGA/VGA display and a 80287. Program Accuracy The accuracy of the positions calculated and plotted vary by a couple of minutes of arc at most. This will produce plots that are well within the needs of an amateur astronomer. StarWorks, however, should not be used for the purpose of Interstellar Navigation (you may get lost). Astronomical Experiments These are just some of the ways you can use StarWorks to watch the heavens move. Many more are possible, it's up to your imagination. * Watch a complete day go by in minutes. To see the Sun, Moon and the planets traverse the sky while you watch it a simple task. Load the predefined setup from fastday.mnu (Use Restore and enter fastday as the restore file name). Select the Horizon view and watch. * Watch the stars circle the North Star as the Earth rotates through a day. The North Star is approximately aligned with the Earth's axis of rotation. If you photograph the northern sky with long exposures you will get a picture with the stars forming concentric circles around the North Star. To create this picture using StarWorks, simply restore the predefined menu 'polaris'. Select the Horizon view and watch. * Watch the Sun's height in the sky at noon change through out the year. As the Earth travels around the Sun, the angle between an observer on the Earth and the Sun changes. On the Winter Solstice the Sun is low in the sky at noon and on the Summer Solstice it reach- es its high point. To see this you can simply restore the predefine menu 'sunheigh'. Select the Horizon view to create the display. * Watch the movement of the Sun during a Summer day above the Arctic Circle. At latitudes above the Arctic Circle the Sun will not set on the longest day of the year, June 21. To recreate this 24 hour day, restore the predefined menu setup 'arctic'. Select the Zenith view and watch the Sun skirt around the whole horizon without ever setting. If you display Planetary Data (from the main menu) you will notice that the Rise/Set time for the Sun is "Never Sets." * Watch the retrograde motion of the planets. The retrograde motion of the planets refers to the way they wander through the constellations from night to night. In fact, the word planet means wanderer. To see this motion, simply restore the predefined menu setup 'retrogra'. Select the Horizon view and let the screen paint. You will see the planets as they wander amongst the stars. * Watch comet Swift-Tuttle nearly strike the Earth. In approximately March of the year 2128 A.D., comet Swift-Tuttle will come uncomfortably close to strik- ing the Earth. To view this occurrence, load the predefine menu 'tuttle'. Select the Solar Orbits display and choose the Zenith view. Watch as the comet nearly strikes the Earth. Caveats Since this program was written on an EGA/VGA system, the displays were optimized to look best in EGA and VGA modes. Although the program does run in CGA mode, the display is of lower quality (due to the low resolution) and is limited in usefulness if any detail is required. Since SuperVGA modes tend to be non-standardized, unpredictable results can occur if a SuperVGA mode is selected which is not supported by the graphics adapter. For the same reason, SuperVGA modes are never selected automatically; they must be forced if desired. The program is very math intensive and needs a math co-processor to run effectively, especially on systems with slow clock speeds. The program will run without math co-processor support. However, the program becomes limited in its display updating due to the long calculation times of the math emula- tion routines. If you have a math co-processor and are interested in seeing just how slow this program will run with- out it, do the following. Before executing StarWorks (at the DOS prompt), type "set 87=n". The program, when run, will detect this value and use floating point emulation routines instead of the math chip. Now that you have seen what a good investment your math co-processor is, you can enable it by exiting StarWorks and typing "set 87=y." NOTE: The " (Quotes) were not supposed to be typed in. Terms of License As the licensee of the Full Function Version (ex- clude limited version) of this program, you may use the program on one computer. If you are an individ- ual (not a company or an institution), you may use the program on any other computer(s) that you own personally. Companies and Institutions must regis- ter one copy per computer or obtain a site license. Copyright Notice If the version number displayed on the first screen ends with '(Limited),' this version of StarWorks is being distributed as a Limited Demonstration ver- sion. Its only limitations are that it will work for a limited date range and that it includes fewer stars/objects in the data base. The Full Function version will work between the years 1700 and 2500. The full function version also includes over 11,000 stars and messier objects. Limitations on distribution and use include the following: No responsibility for the operation of StarWorks is assumed or implied by Sci-Vision. The user of StarWorks uses the program at their own risk. Sci- Vision assumes no responsibly for damages caused by use of this program. This limited version of the program and its documen- tation may not be distributed if any changes have been made. The copyright notice and statement of authorship must not be modified or removed. All copies of the Full-Function (Unlimited) version must be registered and may not be distributed. LIMITED versions of StarWorks may be distributed for a nominal fee not to exceed $5.00(US).