Version date: 2012 Jul 22 The parameters shown in this software are basically the same as those shown in the Windows software, as described at http://www.projectpluto.com/find_orb.htm Commands are very different, because they are all keyboard based (but you can do a few minor things with the mouse; see end of this text.) ? (Or any other unrecognized key) Shows this file (dos_help.txt). ORBIT-FITTING COMMANDS: r Reset R1 and R2, for use in the method of Herget. Results in being prompted to type in new values for both. By default, units are AU, but one can append 'km'; e.g., '.01 500000km' or '10000km 20000km' are interpreted logically. Enter one value, and R1=R2 is assumed. e Reset the epoch. Results in being prompted to enter a new epoch. This can be simply a JD ("2451000.5") or a year/month/day ("2004 10 2"). Or you can enter, say, "+20" to advance the epoch 20 days, or "-40" to set it back 40 days, etc. Or "now" to set the epoch to today, or "now-7" to set it to a week ago. v Find Va'isa'la' orbit. You'll be prompted to enter a perihelion (or aphelion) distance; it will then find a 'best fit' orbit with that apsis distance at the center of the arc. l Set a Limited orbit (e.g, "e=.1", "q=12.4", "a=2.3,e=.15"). h Take one step using the method of Herget. f Take one "full step" using the method of least squares. g Determine orbit with method of Gauss. (There may be alternative solutions; hit 'g' again to cycle through them.) | Determine a Monte Carlo variant orbit. Find_Orb will continue generating variants until you hit another key to stop it. Observe the changes in the orbital elements, and you get an idea of the level of uncertainty. (Elements will also be stored in 'mpcorb.dat'.) : 'Linearizes' the orbit, as described at: http://www.projectpluto.com/vaisala.htm#linearized # Uses a downhill simplex method, as described at http://www.projectpluto.com/herget.htm#simplex / Uses a downhill 'superplex' method, as described at the above URL. u Undo the last orbit-fitting command. F12 Find a circular orbit connecting the first and last positions. Hit this repeatedly, and Find_Orb will iterate through possible solutions. If the arc is long enough, there may be multiple-orbit solutions, including many spurious retrograde ones. INTEGRATION MODEL COMMANDS (perturbers, non-grav effects): 1...9 Toggle inclusion of Mercury...Pluto as a perturbing object. 0 Toggle inclusion of the Moon as a perturbing object. ! If all perturbers are off, turns main planets on; otherwise, shuts off all perturbers at once. a Toggle inclusion of the "big three" asteroids (Ceres, Pallas, Vesta). NOTE that this slows things down a bit and appears to rarely matter. * Toggle inclusion of the effects of solar radiation pressure (SRP). Turn this on, and on the next "full step", Find_Orb will do a _seven_-parameter fit, with the area/mass ratio solved for as an added variable. ^ Toggle on comet parameters A1 and A2. Turn this on, and on the next 'full step', Find_Orb will do an _eight_-parameter fit, with A1 and A2 solved for as added variables. OBSERVATION TOGGLING/WEIGHTING/SEARCHING: F1 Toggle all observations prior to the currently-selected one. F2 Toggle all observations after the currently-selected one. F3 Toggle all observations for the currently-selected observatory. This lets you, say, "shut off all 703 observations." F4 Find previous observation from the current observatory. F5 Find following observation from the current observatory. Both of these functions wrap around at the start/end of the list of observations. F6 Find preceding excluded observation. F7 Find following excluded observation. Again, these both wrap around. F9 Find the first included observation in the arc. F10 Find the last included observation in the arc. % Reset weight of a particular observation. ON-SCREEN DISPLAY: p Show orbital elements with an extra digit of precision. P Show orbital elements with one less digit of precision. + Toggle between "heliocentric-only" elements and default elements. By default, Find_Orb determines the planet with the greatest influence on the object (at the time of epoch) and the elements are relative to that object, so you can get geocentric, Jovicentric, etc. elements. Use '+' to force heliocentric elements only. i Toggles the 'information' about the currently-selected observation (reference, observing station, magnitude/motion of the object). This data takes up three lines; when shut off, three more lines of residuals are shown. j Toggles the two lines showing which perturbers are included, R1 and R2, orbital restrictions, and the step size. When shut off, two more lines of residuals are shown. o Toggles display of the orbital elements. You normally wouldn't want to shut them off, but if you do, ten more lines of residuals are shown. Combine with the above 'i' and 'j' commands, and you can get a full-screen display of observations/residuals. ; Toggles display of the "residual legend", which explains what the assorted data in the residual area mean. c (WATCOM-compiled under DOS version only) Select a different text mode from the default 80x25 one. Modes include 100x50, 132x60, etc. Not all modes may work with your video card. - Toggles display of the list of observatories. (You can also just click on that list.) The observatory for the current observation will still be listed. RESIDUAL-RELATED COMMANDS: Cursor keys : move up/down one observation, or a "page" up/down at a time; 'Home' to first obs, 'End' to last. - Toggles display of the list of observatory codes. x Toggle the inclusion of the currently selected observation. { Filter all observations according to residual level. } Toggle 'precise' residuals. These are more precise than are usually reasonable, but I've had a situation where I wanted to compare residuals at the milliarcsecond level. k Cycle from long residual format to short (such as MPC uses), to showing the original 80-byte observation record, back to the long residual format. b When in "usual" one-obs-per-line residual formats, toggles between decimal day display and HH:MM:SS display. d Show resiDuals in current format & save to file 'residual.txt' t Toggle between "usual" residuals in RA and dec, and residuals in time and cross-track distance. = Toggle between "usual" residuals, and display of total angular residual and magnitude residuals. w Find Worst (highest-residuals) observation. @ Toggle off display of residuals outside the currently-used arc of observations. By default, Find_Orb will compute those residuals; if the observations are quite far from the actually used arc, that can take a while. Toggling them off can help speed things up a bit. ( Compute residuals for _all_ observations. By default, the Herget, Vaisala, and Gauss methods don't bother computing residuals for observations not within the currently-set arc. This speeds up the program, but does require you to hit this key if, for some reason, you want to know those residuals. ] Toggles display of 'deltas': except in the short MPC format, differences between the currently-selected observation and the others, in time, RA, and dec, will be shown. Useful to get a quick how-far-is-this- obs-from-that-one, in time or position. EPHEMERIS-RELATED COMMANDS: m Make an ephemeris. You get a menu asking for a starting date/time, step size, and number of steps. You can also set the observing location (by MPC code) and have a little control over what ends up in the ephemeris Ephemeris-specific help is available from within this menu. MISCELLANEOUS COMMANDS: ) Show a user-selected text file. I added this because I'm sometimes in the midst of solving an object and would like to look at some file or another, without needing to exit or start a new console. n Select a different object from the input file of astrometry. ` (that's a backward-quote-mark!) Toggles between N(uclear) and T(otal) comet magnitudes. When a full-step is done, you'll see that 'M(N)' becomes 'M(T)', or vice versa. s Save orbital elements to a file. (Whatever elements are shown on-screen are also stored in the file 'elements.txt'. This command really just copies 'elements.txt' to a file of your choice.) [ Show covariance and correlation matrices from last 'full step', plus an attempt to extract the largest eigenvalue of the former in hopes of computing uncertainty info. This data is stored in the file 'covar.txt'; this command really just displays that file. q Exit the program COMMANDS NOBODY SHOULD HAVE TO USE (mostly for my testing purposes): z Reset the integration step size, in days. (No longer relevant, except when using the testing-only symplectic integrator.) $ Reset integration tolerance (default is 1e-11). y Show details of the last Gauss orbit computation. z Integrate current orbit forward, then back, a certain number of days, and compare to original result. Used when I suspect the integrator's not quite as precise as it might be, and to evaluate what integration tolerance should be used. " Shows details of Curses mouse commands (these differ from one platform to the next, and I needed a way to puzzle them out). ~ Remove duplicate observations. . Show flavor of Curses. , Show 'debug.txt' (log of debug messages). ' Switch to an alternative 'mpcorb' format. If you really want to know, see comments for elements_in_mpcorb_format() in elem_out.cpp. \ Shift all observations from a given observatory by a given time offset. Used when I was trying to puzzle out some timing errors from a specific observatory for a specific object. Alt-D Reset debug level. Mouse actions: Click on any of the "menu" items on the top line to get that action Click on the R1, R2 display to be prompted to enter a new R1 and R2 Click on a planet abbreviation to toggle its use as a perturber Click on an observation to select it; double-click it to toggle it Click on the "residual legend" to cycle the residual format Click on the epoch to enter a new epoch. Click on the list of observatories to toggle that list. The observatory for the current observation will always be listed. Click on scroll bar at right edge (in 'help', or in ephemerides, or next to the observations in the main screen) to... well... scroll. Turning a mouse wheel may scroll within the list of residuals or within the file you're looking at (depends on the platform; mouse support is a little sketchy in some flavors of Curses.) The following table was shamelessly copied from: http://cfa-www.harvard.edu/iau/lists/Sizes.html It lists the diameters of minor planets corresponding to the given values of the absolute magnitude, H. The diameter is to be read as kilometers when H is in the left-hand column or as meters when in the right-hand column. E.g., H = 8.0 corresponds to a diameter of 65 to 150 km, whereas H = 23.0 corresponds to a diameter of 65 to 150 m. Conversion of H to a diameter for a specific object requires knowledge of the object's albedo. This quantity is not known for most objects, so the diameters listed here are given as ranges: the smaller value corresponding to an albedo of 0.25 and the larger to an albedo of 0.05. Most objects have albedos in this range. If a specific object has an albedo less than 0.05, the diameter will be larger than the upper limit listed here (possibly up to infinity, if you imagine an extremely black "Stealth Asteroid"). If the albedo is greater than 0.25, the diameter will be smaller than the lower limit given here (possibly as low as half the lower limit, if the object is icy and has essentially a 100% albedo... but no lower than that; you can't reflect more than 100%.) H Diameter H 3.0 670 - 1500 18.0 3.5 530 - 1200 18.5 4.0 420 - 940 19.0 4.5 330 - 740 19.5 5.0 260 - 590 20.0 5.5 210 - 470 20.5 6.0 170 - 370 21.0 6.5 130 - 300 21.5 7.0 110 - 240 22.0 7.5 85 - 190 22.5 8.0 65 - 150 23.0 8.5 50 - 120 23.5 9.0 40 - 95 24.0 9.5 35 - 75 24.5 10.0 25 - 60 25.0 10.5 20 - 50 25.5 11.0 17 - 37 26.0 11.5 13 - 30 26.5 12.0 11 - 24 27.0 12.5 8 - 19 27.5 13.0 7 - 15 28.0 13.5 5 - 12 28.5 14.0 4 - 9 29.0 14.5 3 - 7 29.5 15.0 3 - 6 30.0 15.5 2 - 5 30.5 16.0 2 - 4 31 16.5 1 - 3 31.5 17.0 1 - 2 32 17.5 1 - 2 32.5