AlienSun version 3.0
User's Manual
Table of Contents
1.) The Sky Atlas View
2.) Pan and Zoom
3.) Adjusting Basic View Settings
4.) Time
5.) Changing Viewpoint Location
6.) Advanced View Settings
7.) Saving and Printing
8.) Searching
9.) Planetarium and Sun Clock
10.) Asteroids and Comets
11.) Satellites
12.) Catalog Settings and Preferences
13.) Creating Your Own Planetary Systems
14.) Texture Files
15.) Improving Accuracy With Telnet Logs
16.) Processes (for advanced users)
1.) The Sky Atlas View
The Sky Atlas view projects objects onto the inside of a sphere, simulating the geometry of the view from a point in outer space. There are RA/Dec gridlines, constellation lines, constellation labels, star/planet/etc labels, and an ecliptic line.
At the bottom of the viewport are indicators for the field of view, magnitude limit, and current date/time. To get information about a particular object, position your mouse pointer over it. The status bar will then list its name, magnitude, distance, right ascension, declination, and any other data associated with the object.
2.) Pan and Zoom
To pan the view around, place the mouse over a region of empty space and click & drag. Use the left mouse button to pan over large distances, and the right mouse button for smaller distances. If your mouse has a middle button or wheel button, you can use that to pan very small distances. While dragging with the middle or right button, a crosshairs will appear in the middle of the view.
To center the view on a particular object, right-click on the desired object and select "Center [object] in view". You may also select "Keep view centered on [object]" if you wish to track it. Attempting to manually pan the view will have no effect until either "Stop tracking [object]" is selected or a different object is centered in the view via this context menu.
If you left-click on an object, it will be selected and labeled bright greenish white. Certain keyboard commands work on selected objects without needing to use the right mouse button.
To zoom, either use the View->Zoom menu or the * and / keys on the numerical keypad. Pressing the * key twice zooms in 2x; pressing the / key twice zooms out 2x. Holding down Alt while pressing these keys results in a 10x zoom in or out. When zoomed in, more object labels will appear.
You can also set a custom level of zoom by pressing Z. A dialog box will prompt you for your desired zoom, either as a FOV or as a multiplier of the default zoom. To return to the default zoom, press Del. The default zoom is such that your operating system's default window size results in a 90° FOV.
3.) Adjusting Basic View Settings
In some cases, a star may have so many names that the status bar truncates its data on mouseover. To get around this, we've provided the View->Extended Star Info menu item. When this is enabled, all the names for a star will be displayed, however when it is turned off only the default name will be shown. (The default name is its proper name if it has one; otherwise a Bayer-Flamsteed, HD, HIP, or Gliese desgnation is used.)
To adjust the brightness of the objects in the view, press B or Shift+B. Pressing B makes objects appear brighter; more objects are shown, and more objects are labeled. This is because the labels are shown according to a brightness cutoff, and zooming or changing the brightness affects that cutoff. Shift+B has the opposite effect: fewer objects are shown, and they are rendered dimmer, with fewer labels. To revert to the default brightness setting, press Ctrl+Shift+B.
AlienSun version 3 also has an automatic brightness adjust feature. The reason for this will be seen later, in the section where the spaceflight effect is covered. Basically, the auto adjust turns the brightness up when only dim objects are shown, and down when bright objects enter the field of view. You may turn it off if you find it interfering with your desired brightness settings.
The View->Labels submenu contains options for selecting which kinds of objects will be labeled. From here, you can set the application to show star labels according to brightness, proximity, various properties associated with the possibility of extraterrestrial life, or known system orientation. (Those stars listed in the Hipparcos doubles and multiples annex are assumed to be oriented in space so that the equator is level with the orbital plane of the companion star.) You can also turn off star labels altogether, as well as constellation and solar system object labels. For legacy compatibility with users of previous versions of AlienSun, pressing L more than once toggles the brighter star labels option.
Gridlines, constellation lines, and constellation boundaries may also be toggled from the View menu, as can orbit paths and the local galactic plane (typically the Milky Way - more on that later, where we deal with changing location). Orbit paths are turned off by default. There is also the Options->Realism menu item which turns off all lines and labels.
The View->Full Screen option expands the viewport to cover your monitor's entire viewable area. When in full screen mode, the menu bar will not be available, but right-clicking on empty space will invoke the Options menu as a popup, and Shift+right-click will invoke the View menu. (If you right-click and get a regular popup window, it is because the space where you clicked is not empty.) All keyboard commands will work, as will manual panning, select, and popup menu. A green AlienSun style custom status bar will also be shown, to make up for the lack of a Windows style status bar. To exit the full screen mode, press either F11 or Esc. (Warning: pressing Esc when not in full screen mode will exit AlienSun.)
Red light mode is a feature which causes AlienSun to display in shades of red suitable for preserving dark adapted vision. However, in order to fully utilise this feature you will need to go to full screen. Otherwise, your system's taskbar and any background windows (as well as the AlienSun window border) will continue to emit green and blue light. Red light mode also does not affect popup menus or dialog boxes, so excercise caution with these features when preserving dark adapted vision.
4.) Time
As the days progress, the Sun, Moon, and planets progress along their respective paths through the sky. AlienSun 3.0 allows you to display them as they were or will be at any point in time. Press F to advance time forward and E to revert to an earlier date. Using the Shift, Ctrl, and Alt keys in combination with E and F results in the following time increments:
| (No control keys) | Month |
| Shift | Day |
| Ctrl | Half hour |
| Shift+Ctrl | Minute |
| Alt | Year |
| Alt+Shift | Decade |
| Alt+Ctrl | Century |
| Alt+Shift+Ctrl | Millennium |
(The reason for a half hour increment rather than a full hour is given below in the section on satellites.) At extreme time intervals, you will be able to see the precession of the equinoxes, and the proper motion of "fixed" stars. To revert to the current system date/time, press Bksp.
AlienSun will show the current display date and time in the lower right corner of the viewport. It is shown in MM/DD/YYYY HH:MM:SS format with time zone offset, and it is also shown in JD, or Julian Date. You may notice that the current time shown is correct even if it does not match your time zone. This is because AlienSun 3.0 polls the Windows for its system time in GMT, and then performs the proper adjustment for the selected time zone.
To set your location and time zone, go into Options->Locale Settings or press Shift+F2. You will be shown a sun clock with a red X and a list of localities arranged by continent. You may click and drag the red X along the map; choose from the list, or enter your latitude and longitude automatically. (Note: DD:MM:SS values won't work - you need to obtain decimal values for your coordinates, and don't forget the minus sign for southern latitudes and western longitudes.) If the default time zone is incorrect, you may edit it. Also, you may check or uncheck the box that specifies Daylight Saving time. AlienSun 3.0 will correct for DST automatically (therefore Pacific Time for example is ALWAYS GMT-08:00, NEVER -07:00) on the first Sunday in April and the last Sunday in October. If your locality uses a different system, you may adjust the time zone one hour forwards or backwards during the intermediate days.
If your locality is not listed, we recommend Heavens-Above's location database.
AlienSun 3.0 also has a time lapse feature, which advances forwards (or backwards) through time quickly. Select Options->Time->Time Lapse... or press P and a dialog box wil prompt you for a time interval to advance between frames. Decimal points and negative numbers are allowed. Pressing Shift+Pause stops the time lapse.
While you are in this dialog, you can also specify whether you prefer English units (feet, miles) or Metric (meters, kilometers), and at what threshhold to switch from astronomical measurements. Below the threshhold, all distances will be given in your preferred system; above the threshhold, distances will be given in astronomical units (AU) or light years (l.y.).
The location you specify will also affect the topocentric position of the Moon and other objects.
5.) Changing Viewpoint Location
AlienSun 3.0 is more than just a sky atlas; you can use it to chart the view from any celestial object or any point in space. To go to a star, planet, or other heavenly body, right-click it and select "Go to [object]". The viewport will instantly be transferred to that object's location, tilted to its polar orientation (if such is known). Your topocentric position will be whatever you last set your locality to. The Locale Settings dialog box will now display a map of the object you went to, and if there are any surface features included they will be listed. Note that time zones are no longer tied to location and will not change automatically with a change in longitude.
If you go to a galaxy, by default you will see the plane of the galaxy as a series of tiny dots. This can be turned on and off by selecting the View->Local galactic plane menu item. Within the Solar System or any other star in our galaxy, this plane wil be the Milky Way. No matter which galaxy you are within, the galactic center will be indicated, unless of course you are at the center of the galaxy.
The view from the center of our galaxy, looking out towards the Sun's vicinity, is really nice. (Not all Milky Way stars are shown, because we can only map distances to the nearby ones, and therefore have no way to know where to plot them in 3-dimensional space.) Other galaxies are visible above and below the plane of the Milky Way, most noticeably M31.
AlienSun 3.0 also has a spaceflight feature. This is available through the View->Spaceflight submenu, but for convenience you will probably want to learn the keyboard shortcuts. Use the keypad + and - keys to accelerate in the direction (+) or opposite the direction (-) of the center of the view. Panning the view between keystrokes will generate a motion which is the vector sum of all accelerations and in an intermediate direction. You may hold down Shift to move more slowly for interplanetary flights; Ctrl to move slower yet for short distance spaceflights, or Shift+Ctrl for very short distance spaceflights. Holding down Alt while pressing + or - will speed up or slow down motion without changing direction. To stop, press Pause.
If you go far enough out into space, you'll leave the Milky Way and enter intergalactic space. This is where the brightness auto adjust feature comes in handy. Galaxies look dimmer than stars because they are much much farther away. When in intergalactic space, there is not much light and therefore it tends to render as an empty void. When auto adjust is enabled, AlienSun will turn the brightness up rendering galaxies visible within few seconds. The effect is rather nice.
To return to Earth, press R. This also resets the display time to the current system time.
One of the nicest effects that the spaceflight function is capable of is a flyby of a celestial object. This is accomplished by first centering the view slightly above, below, or to one side of the object and beginning a very slow spaceflight. (How slow depends on its distance; for the Pleiades just a simple + keystroke is adequate whereas for the Moon you will want to either start by pressing Ctrl+Shift + or else just Ctrl + and immediately slowing it down with Alt - a few times.) Right-click on the object and select "Keep view centered on [object]". It will then stay in the center of the FOV, and you can speed up with Alt + until the background stars appear to move. You will eventually pass the object, seeing it in 3 dimensions.
At any time during the trip, you can come in closer to your target by pressing the + key; this works because it accelerates in the direction of the center of the FOV, which is your flyby target. If you should find yourself moving too fast, press Alt - a few times to slow it down. Alternatively, you can zoom in during spaceflight to simulate seeing the target at high magnification from a great distance.
You may also wish to right-click the target and select "Watch [object] in status bar". This causes the status bar to behave as though the mouse pointer were "stuck" to the object, and as a result its distance will be continually updated. This way, you can advance rapidly towards your target; otherwise it is often difficult to gauge when to slow down.
6.) Advanced View Settings
The following commands available under the Options menu affect the view as follows:
Automatically update viewport - AlienSun updates the view regularly so as to maintain a real-time feel. For performance reasons, it's not always practical to update it quickly. The default is every 60 seconds, but here you can change that to a faster setting. The fastest is one second. Note that during time lapse and spaceflight, the view will be updated frequently, overriding this setting.
Orientation - This specifies which plane the sky chart will conform to. The default is the local plane, which is the equator when viewing space from a planet or moon. Other options include ICRF, an international standard that represents the Earth's equator at the J2000 epoch; Ecliptic (from Earth), orbit plane (from any other planet or any moon) or local system plane (of the Sun or other star); Galactic, which is the plane of the local galaxy. In certain reference planes, instead of giving RA and Dec coordinates for celestial objects, longitude and latitude will be shown.
Show all features on mousemove - When enabled, panning the view with the mouse does not switch off any of the graphics-intensive screen drawing. Otherwise, panning with the left mouse button will draw a more minimalist view for performance reasons. By default, AlienSun during startup checks the speed of your machine and determines whether it is fast enough to handle this feature. You can always override it here.
7.) Saving and Printing
There may be times when you wish to save or print a view of space. AlienSun 3.0 allows you to save, in BMP format, by clicking File->Save As. There is also an option to save a snapshot every time the view is updated. Needless to say, this requires a lot of disk space and the use of the hard drive will naturally slow down the refresh rate. However, it can be useful for time lapses or spaceflights... you can save all the frames and then combine them in your favorite animation editor to create a video file or animated GIF. To start and stop the saving of frames, click "Save on every redraw" under the File menu. While this option is checked, your images will be saved to the temp subdirectory of the install path.
To print, use the File->Print Setup, Print Preview, and Print commands as you would any other application. However, you probably won't want to print it with a black background. Therefore AlienSun offers the option of showing a white background. Select View->White background or press W to toggle this feature. Incidentally, the white background makes for a nice effect when combined with the spaceflight feature.
8.) Searching
To search for a particular celestial body, click Edit->Search for object... or press Shift+S and a dialog will prompt for the name to search for. Case and spaces are ignored. A star will match if searched by its proper name (e.g. Aldebaran), Bayer-Flamsteed designation (e.g. Alpha Tauri, alp Tau, or 87 Tau), HD catalog number (HD29139), Hipparcos number (HIP21421), or Gliese-Jahreiss number (e.g. Gl.171.1). Planets, moons, and asteroids will match their proper name only, and galaxies will match whatever name is given for them, typically a Messier (e.g. M31), NGC, or UGC number.
Once the match is found, it will be selected and centered in the view. You can go to a selected object by pressing O, thus not requiring the mouse at all.
9.) Planetarium and Sun Clock
To activate planetarium mode, select Options->View mode->Planetarium view or press H.
Planetarium view shows the sky against an idealized flat horizon. Factors such as atmosphere color, light pollution, sunrise/sunset gradients, moisture, smog, and moonlight are all taken into account. Objects near the horizon will also appear dimmer, and their discs redder, just like in the real world. Planetarium views are dependent on the locale setting, and can be used with any planet, moon, or asteroid. However, the reference plane will always be equatorial when in planetarium view.
In the context menu invoked by right-clicking an object, are options to sound an alert when said object rises or sets in planetarium view. For sounding alert on rise, if the object is already above the horizon when this option is selected, AlienSun will wait for it to set or for you to change the time to when it is below the horizon. An audible alert will sound when the object then rises or the time is set so that it becomes visible again. Similarly, for sounding an alert on set, AlienSun will ensure that the object appears above the horizon first. The rise and set functions are independent; they are not required to both involve the same celestial object, and they produce different, easily identifiable and distinguishable sounds.
Sun clock view shows a cylindrical projection with terminator lines delimiting the day and night sides of the globe. By default, individual localities are labeled, however in the case of the Earth the labels tend to get crowded so you may want to turn them off by pressing L. When sliding the mouse over a named locality, the status bar will display its name, coordinates, and local solar time. Right-clicking and selecting "Go to..." will switch to planetarium view as seen from that location.
To return to sky atlas view, click Options->View mode->Sky atlas view or press A.
10.) Asteroids and Comets
Before you can load asteroids or comets, you must download the astorb.dat and/or comets.dat files. These were located at the Lowell Observatory's website, which as of this writing still maintains astorb.dat; both files are also currently available at Strasbourg's site. Decompress the .DAT files if necessary, and place them in AlienSun's install path (typically C:\Program Files\AlienSun but you have the option to change that during installation). They are not shipped with AlienSun.
Once you have downloaded the files, select Options->Add celestial body or press F6. The Add Orbiting Body dialog will come up. Select a category of asteroid from the "by category" drop down list at bottom right.
A list of the largest asteroids will appear at lower left. You may click one and press the button marked "Fill in orbital parameters", or you may type the name of a minor planet into the Search box and press the Search button. If AlienSun finds a minor planet whose name matches the search text, its orbital elements will be filled in. When you have made your selection, click OK and the minor planet will be added to the view, although you may have to search for it to see it.
Note: there are asteroids that have the same name as a moon, for instance Io and Europa. If you search for them, AlienSun will find the moon. This is because each object has an index, and the lowest numbered index to match the search criteria is what's returned. Since the planets and moons are loaded before the asteroids and minor planets, they invariably have a lower numbered index.
To load a comet into the view, after you have downloaded the comets.dat file from the above link, choose Comets from the "by category" drop down list on the Add Orbiting Body dialog box.
You may then select a comet from the list or search the comets.dat file, just as with the asteroids.
Because many asteroids have inclined orbits, the view from an asteroid near the highest or lowest point (with reference to the plane of the solar system) in its orbit, with orbit tracks turned on, makes for a nice effect. Here is the view from 2003 CP20 looking down on the orbits of Mercury and Venus:
11.) Satellites
Please see our notice regarding AlienSun and the use of TLE files.
AlienSun supports the TLE data format. Such TLE files have until recently been available via the CelesTrak website. Unfortunately, the site may be required to discontinue their availability of up-to-date data. We have included some TLEs with AlienSun, so it ships with basic satellite functionality, however this will become less accurate over time unless updated TLEs are added.
To add a satellite to the view, press F6 to pull up the Add Orbiting Body dialog box and select either All Satellites or one of the TLE files from the "by category" dropdown list. You will then be given a list of satellites which you can select from to fill in the orbital parameters. If you wish to add an entire class of satellites (e.g. GPS), type the first few letters of the satellites' collective designation into the textbox next to the "Add all named" button and click that button. If you wish to add all satellites from the list, leave the text field blank. (If you have selected All Satellites, then the entire collection will be searched; if you have selected a TLE then only satellites from that TLE file will be included.)
If you should choose to update the TLE files, you will want to do so frequently, for two reasons. Firstly, AlienSun reads from multiple TLEs when possible and derives values for the precession of the satellite's ascending node and argument of perigee. The International Space Station, for example, currently has an ascending node that precesses roughly 5 degrees every day, and an argument of perigee that processes about 4 degrees/day. The second reason is accuracy; minor course changes must be made once in a while to keep a craft in low Earth orbit (LEO), hence TLEs from, say, a year ago won't accurately predict the position of an LEO satellite today.
AlienSun has an automated TLE update function, however it has only ever been tested on CelesTrak's website. To update a TLE file, select it from the drop down list and click the Refresh button. AlienSun will attempt to refresh the file from the URL stored in the file. Since the default URL points to CelesTrak's site, you will need to either edit the files to point to a different URL or update them manually.
We don't know if the automatic update function will work properly with Space Track, which is the site CelesTrak recommends signing up with to get updated TLE data. Of course if you have an account with them, you can try to copy-pasting the URL of each TLE listing from their site into the first line of AlienSun's .tle files. (This line must begin with a tilde ~ character for it to be recognized as a URL.) Should you decide to attempt this, make sure to first log on to the site through MS Internet Explorer because if the logon saves a cookie, you will need that cookie to automatically update the files.
If that does not work, then you will need to update the files manually. AlienSun 3.0 stores its TLE files in the "TLEs" subfolder of the application's install path. They are in ASCII text format, compatible with Notepad, so you will want to associate them with a basic text editor. The most recent TLE files will be in the root of that folder; older TLE files are saved under subfolders named according to the date when they were superseded. If, for example, it is April 16, 2005 and you refresh a TLE file, AlienSun will create a subfolder named 20050416 and copy the existing TLE file there. Then it will attempt to overwrite the TLE file from the "TLEs" folder with the new file from the website. Take a look at and familiarize yourself with the directory structure of the "TLEs" subfolder and you'll see how the data are stored. Note that the files MUST have a .tle extension for AlienSun to properly recognize them. Note also that if you overwrite a file and do not edit it to include a URL at the top, the automatic update feature will be disabled for that file.
Of course, you can always just enter your own orbital parameters into the Add Orbiting Body dialog box to add custom satellites, asteroids, comets, moons, planets, even companion stars, into orbit around most any celestial object.
When viewing from a satellite, the local orientation is defined as a reference plane that is parallel to the horizon at the point on the Earth's surface that is closest to the satellite, the location on the globe where the satellite occupies the zenith. While it is true that there is no "up" or "down" in space, there is an Earthward direction and its opposite. From the vantage point of a satellite, Earthward is "down". Geosynchronous satellites are often treated as though the direction of the celestial north pole were "up"; for this effect, choose either "Orbit plane" or "ICRF" from the Options->Orientation submenu.
Satellites will by default be displayed as an icon. Click View->Satellite icons or press Shift+I to switch between icons and points. Viewing orbit lines also works for satellites, and are useful in planetarium view for outlining the satellite's path across the sky. In sun clock mode, satellites will be shown at the location of the point on the ground directly "underneath" them, and orbit path lines become satellite ground tracks. Because LEO satellites take roughly 90 minutes to complete an orbit, AlienSun offers a half-hour increment (Ctrl+E and Ctrl+F) rather than a full hour; pressing either key combination 3 times adds up to a 90 minute interval.
Using the Sun Clock mode with a few satellites loaded, enabling icons and ground tracks, leaving the refresh rate at its default value of one minute, and going to fullscreen produces a nice visual effect. NASA uses a similar looking display to track the position of the ISS. Choosing a different display color for each satellite can be of help too, since AlienSun will color the orbit path lines or ground tracks accordingly. When in Sun Clock mode, sliding the mouse over a satellite will reveal the latitude and longitude directly beneath it, and its altitude.
12.) Catalog Settings and Preferences
Clicking Options->Catalog settings invokes a dialog with options for filtering which stars to load on startup, which catalog to get them from, and how many asteroids/minor planets to auto-load. The large catalog takes longer to load than the small, and loading more stars means updating the view will take longer. AlienSun plots every celestial body, including stars, as precisely as possible in 3 dimensional space every time the viewport is drawn.
Options->Display preferences brings up the dialog for adjusting the look and feel of AlienSun. Click on the colored boxes or the buttons marked "..." to change the colors for the various lines and labels. Keep in mind that colors will look lighter and brighter against a dark sky than against the default gray of a dialog box. The Low Gamma option specifies whether AlienSun is to compensate for a low monitor gamma. Most computers compatible with AlienSun have a low gamma, but some video drivers and operating systems have a facility for adjusting the gamma automatically. Uncheck this box if the default setting makes the dimmer stars appear too bright.
You can also select one of the included color schemes, or create your own. Use the drop-down box to select one, or to save your current color settings, press the Add button and type a name for the new scheme. Note that if there is already a scheme by that name, it will be overwritten.
Gamma too low (left) and too high (right).
13.) Creating Your Own Planetary Systems
AlienSun's star, planet, and moon catalogues are fully customizable. This means you can add your own solar systems. The files named _StarCat.dat, _Planets.dat, and _Moons.dat are ASCII text files. You may associate them with your favorite text editor... just be sure to turn off Word Wrap.
The _StarCat.dat file contains lines of data which look like this:
HD19801 03:08:08.0-61:08:59.0 01230.19-00.73+07.18 K2III 19801 14571 J2000+0.024 +0.025 1
Algol 03:08:10.0+40:57:20.0 00092.77-00.18+02.09 B8V 083.98 +137.74 19356 14576 26b Per J2000+0.002 -0.001 +004 2V -00.19 +00.95 0000.0000000 1991.66796122719 00000515.253 00680.0500 000.00.2250 2013.8580
54 Arii 03:08:21.0+18:47:42.0 00569.93+00.01+06.24 M0III 19460 14586 54 Ari J2000+0.038 -0.014 +043 1
HD19819 03:08:22.0-60:10:22.0 00070.05+07.61+09.27 K5V 19819 14587 1056 J2000+0.211 +0.132 1
HD19256 03:08:25.0+57:00:47.0 00103.16+04.14+06.64 G0 19256 14592 J2000+0.130 -0.107 1
HD19641 03:08:26.0-37:51:09.0 00169.62+04.66+08.25 G2V 19641 14596 J2000-0.026 +0.117 1
HD19322 03:08:26.0+51:09:59.0 00970.24-00.39+07.01 A2 19322 14597 J2000+0.013 -0.024 1
HD19521 03:08:27.0+07:38:34.0 00292.90+02.23+07.01 F0 19521 14600 J2000-0.016 -0.019 1
HD19525 03:08:38.0+08:28:15.0 00467.72+00.48+06.28 G9III 19525 14607 J2000-0.003 +0.073 +038 1
The catformat.txt file explains the meaning of the columns of data. Suffice it to say, you probably won't need to modify this file, but you probably will need to copy data from it.
The _Planets.dat and _Moons.dat files have their own plcatfmt.txt and mncatfmt.txt files, respectively. To add planets to a star system, you will need to copy the first several columns of the parent star's definition from the star catalog and add that data to a new line appended to the _Planets.dat file. Then you can fill in the planet orbital elements and other data. When you are done, save the file, go back to AlienSun, and press Ctrl+F5. The catalogs will be reloaded and your new planetary system will be waiting for you at whatever star you chose to put it at.
Here's an example hypothetical 2-planet system to illustrate. We took the orbital elements of Jupiter and Saturn, renamed them, (we also removed the orbital periods - AlienSun will fill them in automatically if they are omitted) and stuck them in everybody's favorite extrasolar sunlike star system:
NAMENAMENAMENAMENAMENAMENAME RA:RA:RA.h±DE:DE:DE.° DISTANCE NAME1NAME1 SMA.SMA INCLINA ORIENTA MMMMMMMMMM RRGGBB IN.IN ASC.NOD PER.PER PER.ARG±ABSMG DIAMETER OBLATE ECCN PERI.OD EQ.IN ±PRE.EQ EQP.HS MMM IMGFILEN.AME RRRRR:RR:RR.RRR MASS.MASS ATMSPH TXO MEAN_LONG
Tau Ceti 01:44:05.0-15:56:22.0 00011.89 C_Adams 005.203 019.8950 C1BDFA 01.31 100.556 004.950 273.878-09.40 0010.973.06487 .0489 003.13 401.07 137.13 005 00009:55:30 0317.8300 FFDD9B 180 034.40438
Tau Ceti 01:44:05.0-15:56:22.0 00011.89 P_Plait 009.537 316.9670 6090AC 02.48 113.715 009.041 339.394-08.88 0009.140.09796 .0542 026.73 1748.4 353.62 009 00010:39:22 0095.1590 FFB763 000 049.94432
Upon going to Tau Ceti, we find both planets have been added. Here is the view after doing a spaceflight up to the inner planet:
And a zoomed-in view of the outer planet:
AlienSun automatically generates fictional planet textures. They are the result of a pseudo random number generator, seeded with the planet's name so that the same planet will have the same texture evey time without needing to save explicit texture data. Later in this document, we will show you how to put in your own textures.
Now we will add some moons to our system.
PLANET NAME SMA_KM ECCN OMEGA M_ANOM INCL NODE PERIOD P_W PNODE LAP_IN LAP_OR EQ_IN EPOCH COLOR A_MAGN DIAMETER ROTATION MASS PRE_EQ EQ_PH TXO HEIGHT WIDTH DEPTH BRAT
C_Adams Ross 31043 .0003 354.0778 150.945 004.738 058.5820 0.289 0.575 110.97 +043.15 20000101.000 909090 +09.81 .0045519 632.5
C_Adams Monica 50381 .0002 212.6123 090.52 000.205 142.0225 0.327 0.654 110.97 +043.15 20000101.000 909090 +09.12 .0062784 721.1
C_Adams Chandler 79721 .0001 282.4269 041.69 000.065 5.503906 0.386 0.773 110.97 +043.15 20000101.000 909090 +07.78 .0116151 817.8
C_Adams Joey 109708 .0001 125.5678 348.31 000.054 285.3589 0.689 1.379 110.98 +043.16 20000101.000 909090 +07.64 .0123999 537.6
C_Adams Rachel 123654 .0014 054.12 034.912 000.201 326.7974 1.255 2.513 110.98 +043.19 20000101.000 909090 +07.20 .0151468 626.9
C_Adams Phoebe 146502 .0004 181.2898 094.96 000.039 217.4241 6.308 12.745 111.10 +043.71 20000101.000 909090 +05.53 .0328049 324.3
P_Plait Ocasek 13980 .0151 037.247 100.293 001.075 344.170 1.131 2.262 117.43 +024.94 02.94 19500101.000 B86352 +11.80 .0117580 106.6 304.48
P_Plait Orr 23460 .0002 292.496 020.51 001.793 339.600 26.892 54.536 116.52 +024.99 03.17 19500101.000 B0A090 +12.89 .0109575 132.4 335.08
Extrasolar moons.
14.) Texture Files
To plot the surface features of a spheroid requires a bitmap file containing some kind of flat projection. AlienSun accepts cylindrical projections, in which each pixel's X, Y values correspond linearly to a longitude and latitude. These bitmaps are known in the 3D rendering field as textures.
A sample texture: the Earth.
AlienSun requires that texture files be scaled equally in both dimensions. They may be any size, but if a texture has a width of 720 pixels then it has 2 pixels per degree of longitude or latitude and therefore must have a height of 360 pixels to cover the whole sphere. If the texture file's height is greater than half its width, the extra pixels will be interpreted as rings. For example, here is Saturn's texture:
The size of the rings drawn on the screen is such that the radius they extend beyond the planet's surface (or cloud tops, as the case may be) will be proportional to the planet's diameter in the same ratio as the excess part of the ring texture to half the texture file's image width. For example, if a planet is 10,000 miles in diameter and its texture file is 500 by 400, then the excess image height (150 pixels) will translate to 150/250 x 10000 = 6000 miles ring radius above and beyond the planet itself.
AlienSun allows a second texture file to be used on the night side of a planet or moon. The day and night textures need not be the same size. A night side texture has the same filename as the day side texture except it has the characters _n immediately before the extension. For example, the Earth daytime texture is named Earth.bmp but the night lights texture is named Earth_n.bmp.
AlienSun ships with a moderate sized selection of texture files, but you will probably want to add more. Any cylindrical projection that is in BMP or JPG format may be used. Simply copy them to AlienSun's application folder. Here are some websites that have texture files available for download:
NASA/JPL maps
Björn Jónsson's planetary maps site
Page of links to various sites, including planetary map sites.
We have included a high resolution map of Jupiter's moon Io. It is a composite made from a very high-res monochrome map and a medium-res color map. Also, we have included artistically generated maps of Pluto and Charon, creatively drawn around known features from existing low-res maps of the actual bodies themselves.
15.) Improving Accuracy With Telnet Logs
Perturbations have noticeable effects on the positions of many natural satellites. Therefore, for greater accuracy AlienSun is capable of reading orbital elements in the format supplied by NASA's Horizons system. Accessing their site via telnet and saving the logs to AlienSun's install path enables this feature.
The data must be requested as Ephemeris, Elements, bodycentric to the planet that the moon orbits, referenced to the ICRF, and covering the desired date range in intervals significantly less than the moon's orbit period. Otherwise, accept all defaults. The smaller the interval, the more accurate the results; we recommend 1/4 the orbital period or less. We have included a few logs we obtained ourselves for some of the larger and more heavily perturbed moons.
16.) Processes (for advanced users)
AlienSun 3.0 includes the following EXE files which you might find running concurrently:
AlienSun.exe - This is the main application executable.
as3online.exe - Handles the updating of TLE files. If this process is not running, the automatic TLE updates will not work.
JPEG2BMP.exe - Automatically converts any JPEG files in the application path to BMP format. AlienSun requires all textures to be in BMP format, but for file size reasons they are shipped as JPGs. The first time the application is run, this process will display a note indicating that it is converting the JPG files. From then on, any new JPGs you save or copy into the install path will be automatically converted to BMPs while AlienSun is running.
This document, the AlienSun 3.0 executable files, and the texture files for Pluto and Charon are copyright (C)2004 by E. Gagnon. All rights reserved.
Windows is a registered trademark of Microsoft Corporation, and is used in this document for descriptive purposes only.
