January 20, 2011, 11:30 am
By Henry Woodbury
A recent news release from the Minnesota Planetarium Society has cast doubt on the assumed alignment of the sun with the astrological constellations. Pshaw, say astrologers, our zodiac isn’t affected.
That’s because Western astrology strictly adheres to the tropical zodiac, which is fixed to seasons. The sidereal zodiac, observed in the East, is the one affixed to constellations, and is thus the one that would change.
In any case, this gives me the opportunity to highlight the digital orrery created by our creative director, Piotr Kaczmarek.
Within the application you can view the solar system according to the Copernican (sun-centered) or Tychonian (earth-centered) model. You can rotate the system by clicking and dragging on the outer ring, or let it move automatically by adjusting a slider in the top left. As for the zodiac display in the model, let us assume that it is the tropical zodiac, and thus needs no recalibration.
UPDATE (April 23, 2011): With the relaunch of our DynamicDiagrams.com web site we have featured the Orrery on its own page where you can view it as an external Flash file or download a Mac or Windows screensaver. I have updated the links in this post to connect to that page.
What a brilliant orrery – very well designed and does exactly what it is supposed to. The user interface is fantastic too. Excellent work!
Posted by El$syd on January 21, 2011 at 7:14 am
This is beautiful. Is there a collection of orrery links somewhere? To be accurate, the apparent location of the planets relative to the constellations *has* shifted quite a bit since Ptolemy’s time, and when your horoscope says you were born with moon in, say, Pisces, chances are your mom would have seen the moon in Aquarius, roughly, if she had looked out the hospital window. It has to do with the precession of the equinoxes over time…the point in the earth orbit where day and night are equal length. Interesting subject, and hard to interpret to the public in sound bites.
Posted by Jeff Beddow on January 28, 2011 at 9:53 am
This is just really gorgeous. Maybe my favorite thing today.
Posted by mordicai on January 28, 2011 at 2:46 pm
No Pluto–not cool!
Beautiful, with great soundtrack–very cool.
Posted by mark v2 on January 29, 2011 at 4:07 pm
Pretty cool! But why is the Tychonian model still shown with Copernican orbital lines?
Posted by Terry on January 30, 2011 at 12:35 am
Wonderful infographic — really elegant! Thank you for posting it — it is one of my favorites. A great way to show off the talents of your studio.
To the earlier comments, I would respond that (a) Pluto is no longer considered a planet (perhaps you missed the big news announcement?) and so is not shown (it was unknown until 1930 and never charted as part of astrology) and (b) the Copernican orbit lines are there because Copernicus knew the planets had to have orbits since they revolved through the sky (I think the original model was that the planets were attached to transparent spheres that held them up in the sky and determined their positions). Kepler and Galileo would have killed to see this working orrery!
Posted by Rembot on January 31, 2011 at 8:48 pm
One (minor) complaint. In the Tychonian model, one can turn on “trace orbits”and see the wonderful loop-de-loops that the planets make as a result of their apparent retrograde motions. However, these traceries rarely persist more than one or two cycles.
Yet ancient and medieval astronomers regarded these loop-de-loops as evidence of higher powers at work — angels, spirits, gods, God — because, when plotted out over decades, they formed precise mathematical patterns.
Your traceries don’t last long enough for those patterns to become visible. Is it possible to have them last long enough for these patterns to appear?
Posted by Andrew Watt on February 1, 2011 at 6:00 am
Thanks for your comment Andrew. We actually had to limit the trace because of memory constraints (though with the most recent version of Flash there is a solution).
What you can do is increase the speed of the orbits to its maximum using the slider in the top left. The curve is plotted with fewer points so more of it can be displayed at once.
Posted by Henry Woodbury on February 1, 2011 at 11:04 am
Brilliant copernican orrery, i agree. But whats happening in the Tychonian model? Lets compare 11-2-1991 and 20-9-1991 in both cases saturn stands 0 degree aquarius, as can be seen in the ephemeris. 11-2 seems to be reasonaly right (but not exact), but 20-9 saturn seems to be standing halfway capricorn! If we look however to the copernican model (for 20-9) and we draw a line from earth through saturn, this line hits about zero aquarius!
I don’t get it. Please comment!
By the way this can’t be explained by the comment Posted by Jeff Beddow on January 28.
Posted by Jos Heddes on February 1, 2011 at 11:11 am
Relative alignments of the planets don’t work because the model is not to scale. If the orbits of the outer planets were in scale to that of the Earth they would have to be plotted many times further away from the center of their orbit. In this model only the angular movement of the planets around the Sun is exact.
Posted by Henry Woodbury on February 1, 2011 at 1:09 pm
It is a really nice orrery. One thing I would ask is if it would be possible to make the orbits ellipses. Personally, it would be prettier and one could tell the seasons. I would like it very much to arrange this to become my wallpaper. (a redditor idea)
However, I don’t know how to interact with flash… Will have to look into that.
Probably you aren’t looking into improving Piotr’s orrery, but since I can’t do it myself, I was just wondering…
Posted by fhtagn on February 1, 2011 at 3:41 pm
Hi Henry, thank you very much for responding, and being so honest about it. But i can’t help wandering: then why implement a tychonian model? if it isn’t accurate. (And surely we must be able to make it accurate mathematically).
Thnx anyhow, for a beautifull copernican performance! Which is ofcourse the most important.
Posted by Jos Heddes on February 2, 2011 at 10:04 am
This is amazing, so beautifully done, and yet a fascinating and worthwhile educational tool. Massive congratulations.
btw fhtagn, seasons are not the result af the orbits being ellipses, but of the tilts of the planets, which are in fact shown.
Posted by Dan on February 3, 2011 at 12:03 am
I find a small bug.
When i drag the speed slider using a mouse, it has a fixed range, but when we control slider using a right and left keyboard keys, it can move right and left unlimited, increasing speed of rotation.
Sorry for my bad english, it not my native language ;-)
Posted by zhyvchyk on February 4, 2011 at 9:49 am
Please don’t delete that bug, zhyvchyk mentioned. It’s a gread hidden feature, to be able to increase speed much more.
In this way, you can see the trace patterns Andrew described. See e.g. http://i.imgur.com/RAQ5H.png
Posted by Til on February 6, 2011 at 3:42 pm
This orrery is so cool – what a beautifully done feature! This would make a lovely screensaver!
We’ve linked to it on NASA Blueshift:
Posted by Maggie on February 7, 2011 at 3:34 pm
This is genius, and beautiful to watch as well. Adjusting the speed is a great addition! I would love to see this displayed large somewhere as a permanent fixture!
Posted by J. Major on February 7, 2011 at 5:29 pm
it’s wonderfull to see u’r work, i love it… perhaps you may consider to make it available for desktop wallpaper, that’s gonna be an awesome…
keep the good work
salam dari indonesia
Posted by uxu axis mundi on February 7, 2011 at 8:25 pm
Good work! It’s perfect visual explanation.
Posted by Andrey on February 9, 2011 at 10:37 am
Some changes are possible? such as the sun is stationary but
model Tychonian everything else is moving.
The energy radiated by the sun moving and the light moves around the
rest on the model “Law of Rhythm” of Pier Luigi Ighina
Posted by DOM on February 9, 2011 at 5:34 pm
Beautiful display! Very cool indeed. Every kid should see this in science class.
Posted by Marc Black on February 10, 2011 at 12:16 am
I have been living in the solar system for many years and I have never seen a prettier orrery than this one. I was surprised and moved by its beauty. I want to send my congratulations to the designer, Piotr Kaczmarek. What is it about Poles and the solar system?
Posted by Joseph O'Dea on February 17, 2011 at 3:47 am
Andrew Watt, you can get complete planetary tracings in the Tychonian model by increasing orbital speed using the right arrow key. As zhyvchyk pointed out, if you ignore the slider and use the arrow, you can accelerate the system right off the scale to sick speed, at which point the curve is plotted with so few points that the entire circuit can be displayed at once.
For the slow-moving outer planets, hold down that right arrow button for a few minutes. With Neptune, you can get it to draw an entire circuit after about 500 years have gone by, which means holding the arrow key for about four minutes to get there. The gain you get this way comes at the cost of squarer tracings because fewer sample points are shown.
Keep a bucket beside you because those whizzing centripetal forces can empty your stomach.
Posted by Joseph O'Dea on February 17, 2011 at 5:13 am
This is the best orrery I have ever seen. My congratulations!
Posted by Yura on April 9, 2011 at 12:43 pm
This is something too exhilarating. I wish i could add it to my website. Could i do that.
Posted by Anantha Narayan on April 10, 2011 at 3:30 am
This is a great illustration of planetary movement and much appreciated.
I especially like the Tychonian presentation. Unfortunately there does seem to be an error in the Tychonian vs. the Copernican view. In the Tychonian, the Earth has Venus as its moon! It’s not rotating around the Sun. It’s rotating around the Earth.
If you could fix that, I would really appreciate it because I like to reference this page.
And I agree with Mark v2, regardless of what some goober astronomer says, Pluto should be on there.
Posted by Jim Ranum on April 14, 2011 at 2:50 pm
Beyond any others I’ve seen!
I would pay for this program, so I could have it as my desktop background.
Thank you for creating, and sharing this with us.
Posted by Pete on April 16, 2011 at 3:53 pm
I would also like to thank you for publishing this. It gives a great overview of how the cosmos works as a system, both heliocentrically and geocentrically. I have mentioned this on my Facebook page and it’s only fair that the many thanks I got for merely posting the link, get forwarded to the creative team which developed it! I would also be happy to pay for something like this that worked as a screen saver – especially if it was able to be easily set to show real time positions and movements.
Wonderful work and thanks for sharing it here!
Posted by Deborah Houlding on April 22, 2011 at 6:45 am