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< ORDER FORM < <(Make checks payable to David Chandler Co., P.O. Box 309, La Verne, CA 91750) < < Registered Copy of DEEP SPACE $49 __________ < (Comes with a copy of THE NIGHT SKY and < EXPLORING THE NIGHT SKY WITH BINOCULARS) < < 3-D Viewer Kit (Purchased with Resistered copy $10 __________ < of DEEP SPACE) < < 3-D Viewer Kit (Purchased separately) $25 __________ < < Unregistered Copy of DEEP SPACE $15 __________ < (For evaluation purposes only. Comes with coupon < for $15 off registration price.) < < (California Residents add 6% sales tax) Tax __________ < < Total __________ < Name______________________________________________ < < Address___________________________________________ < < City/State/Zip____________________________________ < < < < QUICKSTART Type: README to print or list this documentation file CONFIG to specify your system configuration on first startup DS to run DEEP SPACE (fast version--only with 8087 math co-processor) DSS to run DEEP SPACE (SLOW version without 8087 math co-processor) PLANETS to run PLANETS (no 8087 chip needed) (The second disk has six files containing data on 18,000 stars.) DO NOT DELETE ANY OF THE PROGRAMS FROM THE DISTRIBUTION DISK. AS YOU COPY THE PROGRAMS AND DISTRIBUTE THEM TO YOUR FRIENDS AND COLLEAGUES, PLEASE COPY ONLY COMPLETE, UNALTERED DISK PAIRS. When in doubt type <ENTER> for a default or <ESC> to exit. These work many if not most places. It is recommended that you run the programs after a fresh re-boot. Strange things can sometimes happen otherwise. The programs need a minimum of 512k of memory. > | | FEATURES Two clusters of programs are included here. DEEP SPACE and PLANETS. The most unique feature of DEEP SPACE is its ability to produce pairs of star maps which show up in true 3-D when viewed with a special 3-D viewer which is available upon registration of the program. The path of any comet can also be seen in vivid 3-D, swooping in from the distance and returning to the depths of space, either as seen from the earth or from any chosen vantage point in space. This is real data you are seeing: real star distances and real orbits of real comets, either known already or newly discovered! > | | DEEP SPACE also allows you to do all of the following and more: Plot accurate custom star maps, either flat or in 3-D ... for any part of the sky, to any scale ... for any given day, time and latitude ... with or without constellation lines drawn in ... with or without labels ... in your choice of projection system ... to any brightness cutoff down to magnitude 7.2 Compute an ephemeris (an observing schedule) for any comet that is discovered, and plot an accurate finder chart. > | | | | PLANETS allows you to: Plot a planet finder chart for an entire year as seen from earth. Plot planet orbits as seen from space. | For the convenience of teachers, both parts of the program can be plotted for either the calendar year or a school year. > ___________________________________________________________________________ Configuration Considerations HOW TO ... ... get started The first thing you need to do is run the configuration program by typing: CONFIG. This sets up a file called CONFIG.DAT that tells the program how many disk drives, the kind of graphics card and monitor you have, and whether you have an 8087 math co-processor. After configuring, type DS if you have an 8087 math co-processor or DSS (ie. DEEP SPACE--SLOW!) if you don't. > |HOW TO ... ... use different numbers and types of disk drives The configuration program gives the options of using a single floppy drive, two floppy drives, or a hard disk drive. In particular, note that on a hard disk, all files from both the data and program disks must reside in the same directory. ... configure for video board and monitor In its present form DEEP SPACE requires a CGA board (Color Graphics Adaptor) if graphics are to be seen on the screen, whether or not a color monitor is used. If you do not have a CGA board you can still use DEEP SPACE in non-screen-graphics mode. The printouts are not dependent on the screen display. The only limitation in printed output is that you cannot get constellation labels or other text on the star maps, since these must be placed interactively while seeing the screen graphics. > | | |HOW TO ... ... configure for 8087 math co-processor DEEP SPACE should ideally run on a computer with an 8087 (or equivalent) math co-processor. This is because it uses rather heavy "number crunching" in its routines. There are 18,000 stars in the file. Processing time really adds up! The 8087 version can print a star map about 5.5 times as fast as the non-8087 version. Still, you can get the same final results without the 8087 if you are very patient. You might want to take up meditation to help you through the slow parts, especially in the star mapping routines. > ___________________________________________________________________________ Star Map Features HOW TO ... ... plot star maps At the main menu, choose the star mapping option. You will then be presented with three options. Options 1 and 2 are easy to use. To take full advantage of option 3 you must know a little more about the sky. ... plot a star map for the given day and time The first option asks for the day, time, latitude, and magnitude cutoff. Day and time are easy. You can find your own latitude in an atlas, or be adventuresome and choose some other part of the world. > | | | |HOW TO ... ... plot more or fewer stars on your map The brightness of a star is its "magnitude". First magnitude refers to the brightest stars. Sixth magnitude is as faint as most people can see with unaided eyes. The stars in the data file go down to about magnitude 7.2 (18,000 stars). You will want to limit your maps to about magnitude 4 or 5 if you show the whole sky, or they will look too cluttered. If you are selecting a smaller area, going fainter makes sense. > |HOW TO ... ... plot a star map for a given part of the sky You can select any part of the sky with map options 2 or 3. Option 2 decides the scale and projection for you and eliminates options you may not understand if you are a beginner. You choose the part of the sky by selecting a constellation. Option 4 prints out a list of constellations with their abbreviations. Option 3 gives maximum flexibility, but assumes a little more knowledge. If you are a beginner, you can get through option 3 by typing <ENTER> to select the default for options you don't understand. Coordinates may be unfamiliar to you. If you select Equatorial Coordinates, a position in the sky can be selected either by constellation or by numbers. In equatorial coordinates R.A. (Right Ascension) measures around the equator like longitude on the earth, except R.A. is measured in hours instead of degrees (24 hours is a full circle). Dec. (Declination) measures north or south of the equator in degrees just like latitude. The North and South poles are +90 and -90 degrees, and the equator is 0 degrees. > |(cont.) Ecliptic coordinates are most useful when studying motions of objects in our solar system. They are related to the plane of the solar system. Similarly, galactic coordinates are based on the plane of the Milky Way and will be of most interest when galaxies, nebulae, and star clusters are added in a future release. One of the extras that comes with registering DEEP SPACE is a printed star dial called THE NIGHT SKY. Besides being a handy aid for identifying constellations at night, it can be used to look up coordinates. R.A. is marked along the equator. Declination is marked along the radial lines. The projections are a fine point. They are like projections of earth maps. Since the sky appears to be a sphere the idea is to try to flatten it out with as little distortion as possible. For small areas of the sky any of the projections will work fine. For larger areas distortion is of more concern. Stereographic and Mercator projections distort sizes more than shapes: Stereographic exaggerates sizes far from the center, Mercator exaggerates sizes far from a center line. A Gnomonic projection is like a photograph, again best at the center. Polar Equidistant stretches the east- west dimension far from the center. > |HOW TO ... ... plot a 3-D star map We see 3-D in everyday life because we have two eyes that see the world from two different points of view and act like built in range finders. The reason we don't see depth in the sky is because the sun, moon, and stars are all so far away. We can put 3-D back into the view if we exaggerate the separation of our eyes and calculate where the stars would appear from those points of view. The farther apart you place your eyes the more depth there will be. In order to see 3-D you need a special viewer so each eye sees a different view of the universe. > |HOW TO ... ... identify individual stars on a star map Once a star map is plotted on the screen you can identify any star by using function key F2 to bring up a cursor, and using the arrow keys to move it around. Holding the shift key down with the arrow keys makes the cursor take larger steps. Typing the <Enter> key when the cursor is centered exactly on a star will bring up an identification at the top of the screen. Typing any key will clear it. ... connect the constellations to see the patterns The F4 key causes the constellation lines to be drawn on a finished star map. The whole constellations will be drawn whether or not all the stars are present. Most of the stars making up the constellation patterns are brighter than magnitude 4.5, but there are a few that are about 5th magnitude. > | | | |HOW TO ... ... label the constellations on a star map Typing the F5 key causes the program to enter constellation labeling mode. A three letter abbreviation for a constellation will show up at the top left corner of the screen and a blinking cursor will jump to the brightest star in that constellation. Place the cursor wherever you want, hopefully somewhere near the constellation and not overriding the lines or stars. The cursor marks the top left hand corner of the name. Type <Enter> and the name will plop down and the cursor will jump to the next constellation. Continue the process, typing the space bar to skip any constellation, until the process is finished. Typing <ESC> will abort the process. > | | |HOW TO ... ... redraw / zoom Any star map may be redrawn using the F7 key, with options to retain or omit any of the overlays, such as lines, labels, or comet paths. Labels may not only be omitted, but deleted to allow the labeling process to be repeated. Anything that is omitted may be regained by typing F7 again. If you opt for a whole sky view or the North-South printout format in option 3, the stars will look rather crowded on the screen. F7 followed by the up or down arrow keys will allow you to zoom to either the top or bottom portion of the map. The scale of the zoomed map will be approximately the same as the printed output, depending on the size of your monitor, of course. You can return to the original size by typing F7 followed by the <Home> key. > | | |HOW TO ... ... print out a star map F3 will print out beautiful star maps if you have an IBM or Epson compatible graphics printer. If you have a dot matrix printer and the print feature will not work properly, please send in a copy of the graphics instructions for your printer. > __________________________________________________________________________ Comet Features HOW TO ... ... find orbital data on new comets A number of comets are already entered in a file, as you will see when you try out the comet option. You are not limited to these. You can compute the positions of new comets as they are discovered, both to get accurate finder charts and, using the 3-D graphing capability, to gain an intuitive grasp of how they are moving through space. Six numbers are used to determine the motion of a comet. These are called its orbital elements. Whenever a comet is discovered astronomers at the Smithsonian Astrophysical Observatory and elsewhere compute these six numbers from observations. When you enter those six numbers DEEP SPACE can compute an "ephemeris", a timetable of when and where it will appear in the sky. > | | | |(cont.) The most interesting comets are the ones we haven't discovered yet! Many comets come near the sun only once every million years or so. With less exposure to the heat of the sun, they tend to be bigger and give a better display. Comets are essentially ice and dust. They evaporate to form their tails when they come near the sun, but that also makes them wear out. So where do you get the numbers to plug in? As new comets are discovered you can ask at your local planetarium, but only exceptionally bright comets gain the attention of the mass media. If you want to keep up on all the comets that are discovered you can subscribe to various comet news services. (Try Comet News Service, McDonnell Planetarium, St. Louis, MO 63110.) > | | | |HOW TO ... ... enter comet orbit data into the program The six orbital elements have funny names and symbols. Two give the size and shape of the orbit, three are angles that tell the orientation of the orbit in space, and one is the time the comet is closest in the sun. You don't need to know more about them to use the program. Either ignore them or read up on them in an astronomy text. All you have to do is figure out which is which and type them in. > | | |HOW TO ... ... understand the information given in the printout The printout shows the range of dates down the left side of the page. R.A. & Dec --position in the sky R --distance from sun to comet Delta --distance from earth to comet Elong. --elongation, angle from sun to comet seen from earth Phase --for a comet this tells to what extent the tail points away from us (the tail points away from the sun) PA --position angle, the angle counterclockwise from north that the tail appears to extend from the comet --------- Mag. --depending on the information you type in, the printout may have an estimate of the magnitude (emphasis on estimate!) > |HOW TO ... ... plot a comet finder chart The real beauty of this comet ephemeris is that you can save a file of comet positions and access it from the star mapping routine. The custom star map option of the mapping routine can plot a comet path along with an "artificial" tail. The tail is artificial in the sense that it is of fixed length (0.1 A.U., ie. 1/10 of the distance from the earth to the sun). Since the length of the artificial tail is not changing, only the angle of our line of sight and the distance of the comet cause the artificial tail to change its apparent size. A comet is actually like a big chunk of ice. The tail of a real comet will be virtually nonexistent when it is far from the sun. As it warms up coming into the inner solar system the ice evaporates (sublimes) and the dust blows away, often causing a tail to grow, sometimes much longer than 0.1 A.U. A finder chart and a pair of binoculars is frequently all you need to see a "bright" comet. Comets with short periods, on the other hand, have passed near the sun so often that most of their ice has evaporated and blown away. These comets usually have little or no tail and may require a telescope to see. > | | | | |HOW TO ... ... plot a comet path as seen from earth in 3-D If you choose the 3-D option for a star map that contains a comet path a different heading will appear. Since comets are very local compared with the stars, comets and stars can't both be seen in 3-D at once. The comet path will look 3-D and the stars will be flat in the distance. The eye spacing is now given in A.U.'s (Astronomical Units) rather than Light Years. One A.U. is the distance from the earth to the sun. > |HOW TO ... ... visualize the orbit of a comet relative to earth's orbit First, a practical consideration: if you want to visualize the orbit of a comet relative to the earth's orbit, it is best to run an ephemeris for a period of at least a year. The defaults in the program will compute 146 points at whatever interval you choose. That would be two years at 5 day intervals or 4 years at 10 day intervals. The locations of the comet and the earth when the comet is nearest the sun (called the perihelion point) are marked. The mapping routine limits itself to the first 166 positions in this mode due to memory limitations. If you want to see a larger portion of the comet orbit, make the spacing between points larger to keep the total under 166. > | | | |(cont.) If you plot comet paths on star maps as seen from the earth, you may be puzzled by the complicated apparent motions. The complication is that the comet is being viewed from a moving platform, the earth. The earth-based view is necessary for finder charts because most of us are stuck on this planet for life. The view from space, however, makes things clearer. To separate the path of the comet from the path of the earth, choose the option to view the comet from a fixed point in space. You will be asked how far from the sun you would like to position yourself measured in A.U.'s. The viewing direction will be determined by what part of the sky you have chosen to look toward. Your position is chosen so that the sun will be in the center of the field lined up with your chosen part of the sky. > |(cont.) Now the different coordinate systems show their colors. The Equatorial system is tied to the equator of the earth, which seems quite natural as long as we stay on earth. Once we leave the earth tying ourselves to the earth's equator is silly. For solar system objects the Ecliptic system is more natural. The "Ecliptic Plane" is the plane of the earth's orbit around the sun. If you pick a fixed viewing point in space for looking at a comet orbit, the earth's orbit will appear horizontal if you choose to view it in the Ecliptic system. Since the coordinates you specify are the coordinates you are looking toward, a latitude of -90 will put you directly above the solar system looking down. Zero latitude will make the earth's orbit appear to be a horizontal, straight line oscillation, as seen from the earth's orbital plane itself. Even the ecliptic system is provincial when we consider the stars. The solar system is oriented randomly relative to the plane of our galaxy. If you choose to view the orbit of a comet in Galactic coordinates, the galaxy will appear horizontal and the earth's orbit will appear highly inclined. Viewing toward Galactic zero latitude and zero longitude is looking toward the center of our galaxy, in the constellation Sagittarius. Speaking of provincial, the bottom line, of course, is that our own galaxy is oriented randomly in space .... > __________________________________________________________________________ PLANETS HOW TO ... ... run the planet options Type PLANETS to run the planet options. Only one version of PLANETS is compiled on the disk. It does not use the 8087 math co-processor. ... plot orbits of the bright planets The planets Mercury, Venus, Mars, Jupiter, and Saturn are bright enough to be seen easily without optical aid. Venus, Mars, and Jupiter get brighter than any star. The orbit plot routine shows the orbits of these planets as seen by a hypothetical observer hovering over the Solar System. > |(cont.) One use of the printouts is to use push-pins to keep track of where the planets are at any time during the year. The starting point and the time interval are indicated at the top. The easy way to mark out the dates for the earth is to use the dates running along the side of the planet motion graph (see later in this "How To..." file). One of the things to look for is various alignments. Be conscious of the angle between a planet and the sun as seen from the earth (this is called the elongation of the planet). The farther the planet is from the sun, the easier it is to see. When the outer planets are opposite the sun (at "opposition") they are also closest to the earth. This is the best time to observe them, especially Mars, which gets very close at opposition and quite far away at other times. Consider the sun at noon. If there is a planet to the left of the sun (even though you can't see it in the sun's glare), it will follow the sun as the sun moves toward the western horizon. Thus the planet will still be in the sky when the sun sets. Any planet to the left of the sun is visible in the evening sky. Any planet to the right of the sun sets before the sun, but it also rises before the sun, making it visible in the morning sky. > | | | | |HOW TO ... ... plot a planet finder chart Plotting the chart is easy. Choose whether you want a calendar year or school year version (all of these printouts lead to interesting classroom activities for teachers) and the year. The program does the rest. You get a neat chart which you might not understand at first, so keep reading. > |HOW TO ... ... use the planet finder chart to understand planetary motion First, notice that the dates go down the left side. This chart is essentially a calendar. The line down the center represents the sun. We are looking at how the planets move in relation to the sun. Mercury and Venus appear to spiral around the sun (ie. they circle it, but the circle is stretched out along the time axis). The plot indicates when they pass behind or in front of the sun. They happen to change in brightness and phase (like the moon) as they go around it. The outer planets also spiral around the sun, but in the opposite direction. Actually they appear to move backward because the earth is moving faster than they are, so we are constantly passing them by. (The earth is not shown because this chart represents the sky as seen from the earth's point of view.) Try correlating the view of the planets on this chart with the orbit diagrams. It's the same data in a different form. Keep your mind on the angle between the sun and the planet as seen from the earth's point of view. > |HOW TO ... ... use a planet position chart for observations The planet motion chart is an excellent guide to when and where to look for the planets. Mercury, Venus, Mars, Jupiter, and Saturn are as bright or brighter than the brightest stars. All of the planets follow the same general path through the sky called the ecliptic, which is marked out by the motion of the sun through the sky. In order to locate a planet it is usually sufficient to know about how far and in what direction a planet is from the sun. Any planet too near the sun will be hidden by the sun's glare. (Mercury is always near the sun, so it is almost always hard to find.) Any planet to the left of the sun is visible in the evening sky, and any planet to the right of the sun is visible in the morning sky. The outer edge of the chart wraps around. When a planet disappears off one edge, it reappears on the opposite edge. The dashed lines are 90 degrees from the sun, so a planet on the dashed line to the left of the sun is visible "overhead" at sunset. (Actually it will be to the south of overhead if you are a northern hemisphere observer.) When an outer planet is near the outside edge of the chart it is near opposition: overhead at midnight and closest to the earth. The motion of the planets is easiest to detect in the sky when two planets pass. You can use the chart to look for occasions when this will happen. > __________________________________________________________________________ Conclusion This is a start of what I hope will grow into an integrated computer/handbook guide to astronomy. You can get in on the ground floor and participate with the growth of this project by becoming a registered owner, by helping to distribute it to interested friends and colleagues, and by writing in about bugs, incompatibilities, and suggestions for improvements. >