README
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gorbit
My 6-year-old son wanted one of those toy Sun-Earth-Moon orbital models, but shopping online presented me with products that were inaccuate, low quality, unattractive or exorbitantly expensive. I had been meaning to learn Golang for the two years my current job has exposed me to it. So I decided this was an opportunity to learn with an objective in mind, and I named it gorbit (for Go-Orbit)
As my first foray into involved Go programming, one might notice my first attempt can be rather convoluted. In my defense, I was also learning astrophysics through Google. At least I got around to breaking up an even-more-unwieldy single main.go file into objects that were more meaningful. It uses the G3N ("gen") OpenGL 3D Game Engine for Go, which enabled my geometric design without needing to learn hardware system calls. Despite how tangled my code is, Go still manages to render graphical animation at an impressive speed
Notes
Intuition based on Northern Hemisphere, for the current year of 2024 at the time of this writing
Vernal Equinox 2024-03-19
Summer Solstice 2024-06-20 00:00 (Initial Earth position) Epoch Offset 1718841600 seconds. Also happens to be when moon is approximately at Greenwich, England meridian, luckily making initial positioning slightly easier
Autumnal Equinox 2024-09-22
Winter Solstice 2024-12-21
Assumptions
No Euclidean elliptical orbits for now
Lunar plane rotational-Y orientation stays absolutely fixed beyond sun, i.e., it is static to the Earth's tilt axis which results in our seasons, and not to the revolution around the Sun
To Do
Forward backward direction of animation speed
More guidelines that show angles, periods of events
Real time, when you just want to use the app for a live decorative display
Resize and maximize window, redrawing controls optimally
Input fields for setting time manually
Reset button back to initial solstice, or to actual time
Scale distances and sizes correctly
Animating camera reorientation and re-targeting
Render shadow for moon to cast for solar eclipses
Lunar plane angle oscillates over ~18 years
Change simplified circular orbits to actually elliptical
References
https://www.timeanddate.com/moon
Documentation
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There is no documentation for this package.
Source Files