Dear Cluesforum members & readers, Ladies & Gentlemen of this planet,
Precisely one year ago, the musician, researcher, and founder of this forum - Simon Shack, released his TYCHOS model to the world. And as pretentious as this may sound, that event signified the beginning of a new era for mankind. I suggest you go back and read his release note (if you haven't already) before you continue with this one.
One year ago I still hadn't learned enough about astronomy to understand what The Vernal Equinox meant, but now when I have, I am very pleased that Simon chose this particular date or rather point in time for the release of his TYCHOS.
A picture sometimes says more than a thousand words, and a simulation can say even more. So if you want to learn what the Vernal Equinox signifies, I suggest you head over to the hereby released TYCHOSIUM 3D:

. . . and enter yesterday’s date (2019-03-20) into the date box, then hit Enter. Next, open the section called "Objects" in the menu, then check the boxes with the names Ecliptic grid and Celestial sphere. The Ecliptic plane is the plane that our Sun and planets orbit in, and the Celestial sphere is simply an extension of the coordinate system we have here on Earth, but fixed so that it does not follow Earth’s daily rotation. Then use your mouse to zoom in and you will see the yellow ball (representing the Sun) is about to move through an intersecting green and blue line.
Now change the time scale in the menu so that "1 second equals 1 hour", then check the Run box.
The Vernal Equinox occurs when the center of our Sun is precisely in the center (of said intersection), and signifies the point in time when the Sun is precisely above the Equator. This is the most important yearly occasion in astronomy since all celestial positions are calibrated against it. Please note that the Tychosium is not quite accurate enough such that the Vernal Equinox occurs at the most exact moment. But it will be in due time.
Now this point has always been observed to move ever so slightly in relation to the background stars each year. This is what is called the Precession of the Equinoxes. And until last year, no reasonable explanation existed on why this occurred.
If you now go to the date box in Tychosium and enter a 1 in front of the year (thus moving you ten thousand years into the future), you will see that the Earth has moved to a different location in its PVP-orbit, and so has (of course) the Vernal Equinox. And THIS ladies and gentlemen is why the Precession of the Equinoxes occurs. Earth strolls along at window-shopping pace (as Simon puts it), and after 25344 solar years, it has completed a Great Year. Hence, the Precession of the Equinoxes is also complete and starts over.
Tychosium is the result of 6-months of hard work, and vindicates Simon's model just as we had hoped. Simon has put tremendous work in making it as accurate as possible (with astronomical observations), and I dare say it is more accurate than any other existing planetarium. And a nice detail with Tychosium is that the planets agree with star conjunctions (we will get them in place in a future release), and have no need to speed up and slow down in elliptical orbits.
In the coming year we will further develop Tychosium 3D, and make regular releases. Another nice detail is that the math used in the model is dead simple. The planets progress at constant speed in uniform circles. No need for complex and contrived celestial mechanics. To quote Tycho Brahe : "So mathematical truth prefers simple words since the language of Truth itself is simple”.
Tychosium 3D is now GNU licensed Open Source. This means that you can use it, distribute it, and modify it in any way you like, provided you release any improvements as GNU licensed Open Source as well. Tychosium is made with a 3D/WebGL framework called Three.js.
Many thanks to the authors of that. If you are a developer and would like to help out, contact me or Simon. At the moment Tychosium is just hosted on Codepen. A GitHub and dedicated site would be nice, but I simply haven't had the time to set that up. More hands are definitely needed here.
Now if you feel as joyous about this moment as I do, I suggest you head over to Bandcamp and buy all of Simon’s records (for a generous amount) since it's really good music and to make sure he can keep doing what he does. Then listen to “Precession” from the album Something Fishy at high volume and then round it off with “By the Balls” from the album Songs in Vacuum. Yup, we got them Simon. :-)
The TYCHOS is a wonderful and remarkable feat. Arguably the most important intellectual achievement ever made in human history. So thank you for that Simon!
Sapere Aude!
/Patrik Holmqvist, March 21 2019