Results for "Author: jay tanner"

Some basic high-precision math functions This little program demonstrates the ability of VB to go beyond the built-in 16 digit level of precision. It demonstrates the computation of the sine, cosine, tangent, square root and cube root of an argument to a precision of up to 28 significant digits. In my work, I often encounter special situations where a higher level of precision is required, so I thought I'd share some of the basic routines I use to achieve it.

An external function module to compute higher precision math functions for special applications.

Sub utility for displaying an image of the moon as viewed from a given phase angle.

This program will generate a quiz for the user. Quiz data files can be written using a plain text editor such as NotePad and can be on any subject and can have as many questions as desired. Each quiz question can have from 2 to 6 possible multiple choice answers for the user to guess. Two example quiz files are provided with the source code to demonstrate the program and the format of the quiz data files. The program is relatively simple and can easily be expanded upon.

SUN EPHEMERIS GENERATOR V1.5 Program written by Jay Tanner - Jay@NeoProgrammics.com It was built around revision 6 of the VSOP87 core modules. ====================================================================== The program is based on an implementation of the full VSOP87 theory computations of the orbit of Sun in spherical variables. The original VSOP theory was developed of Pierre Bretagnon et al. of the Bureau des Longitudes in Paris and was implemented in the FORTRAN computer language. Theoretically, the heliocentric coordinates upon which the geocentric computations are based are accurate to within an arcsecond or better over the range from 2000 BC to 6000 AD in the case of the inner planets, Mercury to Mars. Due to the popularity of Microsoft Visual BASIC and the much faster speed of modern computers, I thought it was about time to develop a version of the theory that would be more accessible to the amateur astronomers with Windows PC computers. The result of that effort is the development of a series of ephemeris generating programs for the Sun and the eight major planets from Mercury to Neptune. The computations of the planetary positions include the interacting gravitational perturbations of the planets, precession, the long-term effects of relativity, light-time, aberration and nutation. Then the coordinates of the planets are reduced from the dynamical coordinates of the VSOP87 theory to the apparent geocentric coordinates according the standard J2000 FK5 system of coordinates. Consequently, the computations compare very favorably with the published ephemerides. The basic ephemeris computations are: Apparent Geocentric: Right Ascension Declination Distance to the sun Semidiameter The planetary orbits are determined by the computation of three spherical variables. These variables are: L = Heliocentric longitude B = Heliocentric latitude R = Radius vector or distance between centers of Earth and Sun Program Statistics for the Sun ephemeris program: Total Computational Term Counts For the VSOP87 Orbit of EARTH are: Total # L Terms: 1080 Total # B Terms: 348 Total # R Terms: 997 Total All Terms: 2425 The Earth module is used to compute the position of the sun. This is the simplest case, since the Sun may be considered directly opposite the Earth. In this case, the position of the Earth is computed and 180 degrees is added to its heliocentric longitude and the sign of the Earth's heliocentric latitude is reversed. The radius vector requires no modification. ======================================================================

This is a simple demo of the raw methodology involved in the basics of plotting 3D points on a 2D monitor screen. All this simple program does is compute the image of a cube one point at a time with a circle drawn on the front face. Anyone who wants to learn the elementary math involved in plotting a point in 3D space onto a 2D monitor can study the source and experiment with various viewpoint settings in the interface to see how they interrelate and effect things. Each of the X,Y,Z axes are color coded as RGB respectively help to keep track of the image orientation. Many comments in the code explain what each part does.

PROGRAM NAME: Geo_Dist VERSION: v2.0 PURPOSE & DESCRIPTION This program computes the geodesic surface distance between two locations on the surface of the Earth to an accuracy of about ±50 meters. Instead of assuming the Earth to be a perfect sphere, this program takes into account the actual polar flattening of the earth and the equatorial bulge, which gives a much more accurate computation between the given coordinates. The coordinates arguments are given in degrees minutes and seconds and the computed distance may be returned in kilometers, statute miles or nautical miles.

NeoEphemerix 2001 - v1 Beta 2 Written using VB 6 Requires 800x600 display or better This program is for astronomy hobbyists who want to create their own custom VB astronomical almanac program. It is a very complex program consisting hundreds of thousands of orbital computations and represents about 6 month's work so far. The program will generate high-precision ephemerides for the sun and planets from Mercury to Neptune. It has reached the beta level of functionality and I encourage any fellow astro-computationists to give it a try and offer any comments, bug reports and suggestions regarding it. Anyone who ever wanted to learn how to perform their own high-precision planetary orbit computations, may find the source code helpful, but the math required is rather advanced. A new version with even more computations is in the works. Any suggestions from users of this program will be considered in the design of future upgrades. NOTE: Due to the enormous size of the mathematical core modules and the complexity of the computations required to get almanic-like accuracy, the program takes about 30 minutes to compile into an executable on a 200 MHz machine and will produce a finished program about 4.3 megs in size. The visual magnitude computation of the planet Saturn will be applied to a future version, but magnitudes are computed for the other planets. The allowance for the rings contribution to its brightness hasn't been formulated yet. This version of the program does not yet specifically check to see if the date entered is in the proper range for the selected planet, so the following table is provided as a guide. VSOP87 Heliocentric coordinates are theoretically accurate to an arcsecond or better within the following ranges: Mercury to Mars - 2000 BC to 6000 AD Jupiter and Saturn - 1 BC to 4000 AD Uranus and Neptune - 6000 BC to 8000 AD To any users familiar with the astronomical algorithms of Jean Meeus and others, this program applies many of the same concepts, but at a higher level of precision not possible from the limited tables applied in the popular books on astronomical computing. It is based on a Visual BASIC implementation of the full VSOP87 theory of planetary orbits in spherical variables. Its theoretical heliocentric accuracy is to within ±1 arcsecond or better over the ranges specified for each planet in terms of dynamical time. Since the full theory is implemented, the accuracy of the orbit computations compares very favorably with the published almanacs. To achieve this level of accuracy, over 30,000 computational terms are applied to the raw, dynamical orbit computations. The computations include corrections for precession and the long-term effects of relativity on the orbits. Then corrections are applied for light-time, aberration, reduction to the standard FK5 system of coordinates and nutation. FEATURES INCLUDE: Both VSOP87 heliocentric and apparent geocentric ecliptical and equatorial coordinates Ephemerides tables can be generated by the day, hour or minute and can be saved to disk as plain text files Allowance for delta-T can be applied when known. Distances to the planets from the sun or Earth can be displayed in astronomical units, millions of kilometers or miles. Hour angles may be displayed in hours minutes and seconds, decimal hours, degrees minutes and seconds of arc or decimal degrees. Latitudes may be displayed in degrees minutes and seconds of arc or decimal degrees. A table showing the VSOP heliocentric position and geocentric ecliptical and equatorial coordinates for the sun and the eight major planets at any given moment can be displayed Basic astronomical data such as the mean and apparent obliquity of the ecliptic, mean and apparent sidereal time at Greenwich and nutation in longitude can also be computed. The program also has a stay-on-top feature that can be toggled to lock the window in front of other windows when needed. All program settings are preserved when the program terminates and are recalled the next time the program starts up. This program is still a rough draft but functional enough to be useful. I would appreciate any feedback on user of this code who are also into astro-computing, since it would help me to improve on future implementations.

Some basic high-precision math functions This little program demonstrates the ability of VB to go beyond the built-in 16 digit level of precision. It demonstrates the computation of the sine, cosine, tangent, square root and cube root of an argument to a precision of up to 28 significant digits. In my work, I often encounter special situations where a higher level of precision is required, so I thought I'd share some of the basic routines I use to achieve it.

An external function module to compute higher precision math functions for special applications.

Sub utility for displaying an image of the moon as viewed from a given phase angle.

This program will generate a quiz for the user. Quiz data files can be written using a plain text editor such as NotePad and can be on any subject and can have as many questions as desired. Each quiz question can have from 2 to 6 possible multiple choice answers for the user to guess. Two example quiz files are provided with the source code to demonstrate the program and the format of the quiz data files. The program is relatively simple and can easily be expanded upon.