I was able to work on this project some this weekend, and got my first gearing completed - that of the Moon revolving around the Earth. It looks reasonably accurate, but I note I still need to add orbit inclination and axial tilt for the Moon, and also I need to represent the Tidal Locking of the Moon. This will add a little more gearing on the end of the Earth orrery arm. When I complete this and am satified with my results, I'll post a short video.
I know it sounds trivial to have a single orbit represented, but it was a significant step for me to get some gearing down, attach it to an arm, and make sure all the gears were connected and wired correctly. 3DS Max is very finicky with odd angles and mixed rotation speeds, and it took some time to get all the parent/child relationships correct. Also, I managed to get the Earth's clouds to spin at a different rate than the surface, for added realism. I created all the spur gears, bevel gears and helical gears from scratch, and got them all to rotate at the right speeds/angles. Now, I'm just double checking my math to make sure all the orbits will be right in the end. My gearing table has all the orbits accurate to within 0.06%, or less than a minute over the course of a year.
Monday, September 13, 2010
Friday, September 10, 2010
Gearing Problems
Not much progress made last night. I started looking at gearing ratios for the various planets and moons to "downgear" from one planet to the next. For example, when I look at Jupiter and its four moons, if I start by using Callisto's orbit as the drive gear (rotating once every 16.689 days), I can successively downgear from that for Ganymede, Io, Europa and Jupiter's rotation (the fastest at 0.414 days), in order.
After thinking about gearing though, I started thinking about moon inclination from Jupiter's equator, and how to represent that, and also the axial tilt of Jupiter itself. Trying to model this in 3DS Max turned out to be a bust, as I cant figure out how to turn gears at angles that are not 90 or 180 degrees. Maybe I'll make some progress on this later this weekend.
I think likely all moons in my orrery will be modeled with circular orbits due to their extremely low eccentricities. Also, I plan to not model the rotation of the moons themselves. That should make for less weight on the end of the arms from gearing mechanisms.
After thinking about gearing though, I started thinking about moon inclination from Jupiter's equator, and how to represent that, and also the axial tilt of Jupiter itself. Trying to model this in 3DS Max turned out to be a bust, as I cant figure out how to turn gears at angles that are not 90 or 180 degrees. Maybe I'll make some progress on this later this weekend.
I think likely all moons in my orrery will be modeled with circular orbits due to their extremely low eccentricities. Also, I plan to not model the rotation of the moons themselves. That should make for less weight on the end of the arms from gearing mechanisms.
Wednesday, September 8, 2010
Planet Photos
Ok, so here are my orrery solar system photos so far. Note that axial tilt and planet locations are not yet accurate - I simply lined them up in a row for ease of viewing.
The Sun. Underneath its glow, I rendered solar flares and sun spots:
Mercury, the closest planet to the Sun and smallest in our solar system. Basically, a cratered iron ball that zooms around the Sun four times a year:
Venus. It has always seemed wierd to me that the planet named after the Greek Goddess of Love is dotted almost entirely by massive surface volcanos and sufluric acid lightning storms. I guess "Hell hath no fury...", ahh nvm:
The Earth and the Moon. I added additional layers for clouds and atmosphere, so if I really wanted to I could rotate them at different rates for added realism. Note that the Moon is one of many natural satellites that is tidally locked with Earth, meaning we always see the same side of it (I'm not sure the side currently facing it is the right side though =D ):
Mars. Authors such as Edgar Rice Burroughs wrote entire novels about beings from Mars, likely due to the fictional canal system documented in the early 1900s. Instead, my render shows the heavily impact cratered surface photoed by Mariner 4:
Jupiter and four of its largest moons, Io, Europa, Ganymede, and Callisto. I added Jupiter's ring system, which is hard to see from Earth, except for the Hubble Space Telescope:
Saturn and five of its largest moons, Tethys, Dione, Rhea, Titan and Iapetus. The first two moons are Inner Moons and actually are within Saturn's E-Ring, but my render only includes out through A-Ring, for ease of orrery modeling purposes. Also, see how I attempted to convey the fact that Titan is the only moon with a dense atmosphere, comprised primarily of Nitrogen, Methane, and Hydrogen. The other 4 are barren rocks. Titan may also have extraterrestrial life in its oceans, just like Jupiter's Europa:
Uranus and four of its largest moons, Ariel, Umbriel, Titania, and Oberon. Note how all of Uranus' moons are named after Shakespearean characters. Also, note that this is an unrealistic viewpoint for Uranus, whose rings appear near vertical with respect to the ecliptic when seen from Earth:
Neptune and its largest moon, Triton. I couldn't find any texture maps for the ring system, so I made my own, where you can make out Neptune's three main rings:
Each of the planets and moons in my orrery design is rendered in full detail for close ups. For example, see this zoom in on Ganymede:
The next step is to put the planets and moons in their actual present locations, and also add correct lighting and shadows to demonstrate eclipses.
The Sun. Underneath its glow, I rendered solar flares and sun spots:
Mercury, the closest planet to the Sun and smallest in our solar system. Basically, a cratered iron ball that zooms around the Sun four times a year:
Venus. It has always seemed wierd to me that the planet named after the Greek Goddess of Love is dotted almost entirely by massive surface volcanos and sufluric acid lightning storms. I guess "Hell hath no fury...", ahh nvm:
The Earth and the Moon. I added additional layers for clouds and atmosphere, so if I really wanted to I could rotate them at different rates for added realism. Note that the Moon is one of many natural satellites that is tidally locked with Earth, meaning we always see the same side of it (I'm not sure the side currently facing it is the right side though =D ):
Mars. Authors such as Edgar Rice Burroughs wrote entire novels about beings from Mars, likely due to the fictional canal system documented in the early 1900s. Instead, my render shows the heavily impact cratered surface photoed by Mariner 4:
Jupiter and four of its largest moons, Io, Europa, Ganymede, and Callisto. I added Jupiter's ring system, which is hard to see from Earth, except for the Hubble Space Telescope:
Saturn and five of its largest moons, Tethys, Dione, Rhea, Titan and Iapetus. The first two moons are Inner Moons and actually are within Saturn's E-Ring, but my render only includes out through A-Ring, for ease of orrery modeling purposes. Also, see how I attempted to convey the fact that Titan is the only moon with a dense atmosphere, comprised primarily of Nitrogen, Methane, and Hydrogen. The other 4 are barren rocks. Titan may also have extraterrestrial life in its oceans, just like Jupiter's Europa:
Uranus and four of its largest moons, Ariel, Umbriel, Titania, and Oberon. Note how all of Uranus' moons are named after Shakespearean characters. Also, note that this is an unrealistic viewpoint for Uranus, whose rings appear near vertical with respect to the ecliptic when seen from Earth:
Neptune and its largest moon, Triton. I couldn't find any texture maps for the ring system, so I made my own, where you can make out Neptune's three main rings:
Each of the planets and moons in my orrery design is rendered in full detail for close ups. For example, see this zoom in on Ganymede:
The next step is to put the planets and moons in their actual present locations, and also add correct lighting and shadows to demonstrate eclipses.
Creation of the planets
So, I worked on the 3D modeling of planets and moons all day and finally got where I think I need to be. I ended up modeling all 8 planets in the solar system: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. I found out after many tries that using a logarithmic scale is trickier than I thought. It is fine for the Terrestrial Planets, because they are small to begin with and spread out easily. However, the Jovian Planets turned out to be much more difficult to fit into a log scale. Because of their great distance from the sun, a log scale really squashes them together. This was mainly because each of the gas giants has a ring system that extends hundreds of thousands of kilometers out past the planets equator, and then there are moons beyond that. Also, I did decided to limit myself to only moons of 1000 km in diameter in size or larger, which eliminated Ceres as an option, and also some of the more well known moons, such as Mars' Deimos and Phobos. But in all, I ended up modeling 15 natural satellites including Earth's Moon, and the largest moons of Jupiter, Saturn, Uranus and Neptune. If I do eventually add dwarf planets, then Pluto, Eris, Makemake, Haumea, and Pluto's Moon Charon should be added as well. This might make the orrery arms to long and mechanically unstable, though.
Also, I got through the challenge of making planet rings for Jupiter, Saturn, Uranus and Neptune. It turns out that thanks to the Cassini Orbiter, there are really detailed high resolution NASA surface maps for all of Saturn's moons and the ring system. The four Galilean moons of Jupiter also have pretty nice surface maps due to the Voyager 1 flyby. Uranus and Neptune did not have as detailed surface maps or ring maps, and I found myself creating them from the few images on Wikipedia. I ended up using Paint Shop Pro to convert spherical photos into rectangular surfaces. So you may notice some of these maps are incomplete, or not precisely accurate.
In all, 8 planets and 15 moons was plenty of modeling, considering I had to calculate accurate logarithmic distances from the sun (I used perihelion), radii, satellite orbit distances, etc. I'll post some pics of these planets and moons tonight. The next step is to start modeling their elliptical orbits around the sun, and to figure out where gearing needs to be.
Also, I got through the challenge of making planet rings for Jupiter, Saturn, Uranus and Neptune. It turns out that thanks to the Cassini Orbiter, there are really detailed high resolution NASA surface maps for all of Saturn's moons and the ring system. The four Galilean moons of Jupiter also have pretty nice surface maps due to the Voyager 1 flyby. Uranus and Neptune did not have as detailed surface maps or ring maps, and I found myself creating them from the few images on Wikipedia. I ended up using Paint Shop Pro to convert spherical photos into rectangular surfaces. So you may notice some of these maps are incomplete, or not precisely accurate.
In all, 8 planets and 15 moons was plenty of modeling, considering I had to calculate accurate logarithmic distances from the sun (I used perihelion), radii, satellite orbit distances, etc. I'll post some pics of these planets and moons tonight. The next step is to start modeling their elliptical orbits around the sun, and to figure out where gearing needs to be.
Inspiration
I've started falling behind in my blog on this project, but I did promise to post my inspiration for this development:
So, I’ve decided to design an Orrery. I’ve been thinking about it for about a month now and I find myself lying in bed awake at night and mumbling orbital characteristics to myself throughout the day. I decided that writing this blog about my experience developing one might help keep my thoughts clear, keep my sanity, and help anyone else who decides to try this. Also, I’ve got to hand it to my wife, who puts up with my endless nonsense in thinking about these things.
First of all, while you likely don’t even know what an Orrery is, you probably have seen one. In simple terms, it’s a mechanical model of our solar system. They are typically constructed of brass, but in my research the last four weeks, I’ve seen them also constructed out of wood, stainless steel, aluminum and other materials. Ancient civilizations such as the Greeks knew how to construct them as early as 150 BC, evidenced by the Antikythera mechanism, discovered in a shipwreck off the coast of Greece in about 1900. Orreries are designed to compute the planetary orbits of our planets around the sun, in a heliocentric model. I’m not going to go into the whole history of Orreries; you can read about them on Wikipedia.
I have always been interested in technologies that as modern day people we seem to have forgotten how to develop. There is evidence worldwide that many ancient civilizations knew how to construct mechanical marvels to handle complex calculations, and an Orrery is one such device. With modern day computers, we seem to have lost the technology to build devices like this, and after investigating it for two weeks, it’s not as simple as it seems. There are not any plans readily available on the internet, and I’ve only found about one company that sells an orrery kit. It appears that maybe plans are available in print form, but again, finding books written in the 1700s may be challenging. One guy built a custom one out of wood, which is very nice, btw. Also, another guy has a really beautiful vertically mounted mechanical clock device, that has similar characteristics to an orrery, but was not quite what I was looking for (but is beautiful nonetheless). In any event, it appears that my orrery will be harder to construct than I first imagined. I just found this great website today that has gearing ratios for the planets that I’m sure will come in handy (more on this later).
Because we are in the modern day of computers, I thought I would design my orrery first on a computer, to get all the sizes and gearpieces accurate. If I make any construction mistakes, they are easily correctable in the virtual world. Also, as I lack any brass machining skills or equipment, if I am unable to ever physically build the orrery, at least I can watch it animated on my PC. Plus, maybe someone will come along with machining skills that can help me out. I happen to have several 3D modeling softwares at home, and the one I decided on is Autodesk 3DS Max. I picked it because not only can you model things in 3D, but also you can animate objects and output video files of the animations. However, I have an older version – 3DS Max 7, and it lacks some of the features of the current version. Also, I have not taken any 3DS Max training or courses on how to use it, and so I have to stumble through the exceedingly complicated user interface. It has tons of features, but I’d be surprised if I know even 5% of them.
Off on somewhat of a tangent here – what initially inspired me to do this was the virtual orrery that appears in the Second Life world Nemo, which btw is absolutely fantastic. Here is the direct link, if you happen to have Second Life installed. I first joined SL because of some online friends who said it was a great gathering place. But, in general, I got rapidly bored with seeing virtual people just standing around in various virtual locations not doing anything. I only recommend Nemo because it is just visually inspiring and highlights many of the types of technologies (in Steampunk fashion) that I’m attempting to capture in developing a device like an orrery. I salute Nemo’s designer, Sextan Shepherd, for this masterful virtual world. BTW, my next favorite device in his world is the Tesla Clock… absolutely stunning!
So, let me synopsize my progress to date now that I’ve started this blog:
I have started the modeling in 3DS Max, and realized quite a few things. Knowing what you don’t know can be pretty daunting to say the least!
First, the actual planet orbits, distances and size are far too great to model to scale. For example, if I place the first four planets (Mercury, Venus, Earth and Mars) within an inch of the Sun in my orrery, the furthest out planet, Neptune, would be nearly 20 inches out (at actual scale). If I also include the dwarf planets Ceres, Pluto, Haumea, Makemake, and Eris, this might go out as far as 64 inches in radius! This would make the planets hard to see and also gearing would be significantly compressed on nearer planets. In addition, for solar system body size, the Sun has nearly 109 diameters that of Earth, while the largest planet, Jupiter, is over 11 times the size that of Earth. I started my model to scale, and realized that it would make for a rather unwieldy and maybe not very nice to look at orrery. Earth looks like a mere dot against the background of the Sun.
Instead, I plan to model all my planet orbital distances and planet/moon equatorial radii based on a Base 10 logarithmic scale. That will make the smaller planets and distances seem larger, and further out planets closer in. Also, I can put a logarithmic scale marks on the planet arms to show actual distance from the Sun. Also, I plan to use a logarithm multiplier so that the planets don’t compress so much that the gearing overlaps each other.
Also, I became concerned with the “look” of the planets in my model. Those of you who have 3DS Max may know that it comes with some Planet textures already for putting on spheres of various sizes (in the tutorials). However, I noticed that the textures have seams and aren’t very nice for 360 degree viewing (or maybe I just don’t understand UVW mapping very well). In any case, I found this website that has some great planetary textures for downloading, including some bump and specular maps for terrain. It even had texture/transparency maps for some of the planets rings, like Saturn and Uranus for example! These look very nice when rendered. I'll post some pics tonight.
I had some challenges figuring out how to map textures to the ring planets Jupiter, Saturn, Uranus, and Neptune. I started with Saturn first and it kept messing up the texture orientation on the model of the ring system. Also, I suppose I’ll have to make some maps for Jupiter and Neptune, based on images from Voyager on Wikipedia. Again, the rings for all four planets also have inner and outer radii that need accurate distance modeling (on a logarithmic scale). Also, I’m assuming at this point that the rings orbit the planets around their hemispheric equator, but I’m not entirely sure. Further, I need to figure out what to do with the “transparency maps” of the rings.
My intent is to convey both orbital revolution around the sun and planetary rotation on its own axis in my orrery. Each planet has its own axial tilt which will have to be modeled, and some even spin in the opposite direction (retrograde), like Venus.
Planetary satellites also become a problem. For more moons, more gearing is required. Jupiter has 63 moons! That would be nearly impossible to develop, and so I’m going to try to limit the maximum number of moons per planet to maybe five of the largest ones. My intent is to pass out two spin speeds on each orrery planet arm (via rotating cylinders), the planet orbit speed and the planet rotation speed. Moon orbital speeds will have to be derived with additional gearing on the end of the arms. Also, I probably won’t model the axial tilt or rotation speeds of satellites, as this would be entirely too much work, except maybe for the Earth’s Moon itself.
Some other things I realized in my first attempt at modeling, was that the orbits of planets are not circular. They are only “roughly” circular, and really follow elliptical paths around the sun. I was using the Semi-Major Axis distance as my distance from the Sun, which could be used if my model was entirely circular, but could be wildly inaccurate for highly eccentric orbits, like that of Mercury. Hence, I had to compile a table of Aphelion and Perihelion distances and consider how to model them. Now, the challenge I am faced with, is that elliptical orbits could be much harder to model mechanical gearing for. Perhaps, it is possible I could use gearing somehow to create a mechanically driven Trammel of Archimedes for my ellipses, but I’m not sure yet.
Additionally, the planetary orbits are not all exactly on the ecliptic plane, each offset slightly by a number of degrees (Mercury, for example is 7 degrees off-axis). Pluto, if I choose to model the dwarf planets, has over 17 degrees of inclination. If I want to accurately represent that, my planet orbits all have to be slightly inclined with respect to the Earth’s rotational orbit (Earth inclination = 0 degrees), and also, they have to be pointed in a particular direction on the orrery, using the angles of the other two axes: the Longitude of the Ascending Node and the Argument of Perihelion.
Also, I just realized today that the planet speed around a given orbit is not a constant velocity. That could present some serious mechanical challenges to say the least. You can see now why using orrery mechanics to model planetary motion are starting to make my head hurt!
Ultimately the goal would be to actually build my orrery, but obviously tools, gears, equipment, and of course cost could prevent that. I figure I’ll just start with the computer generated model and see how it goes. As I’m just sort of outlining my project goals in this post, I’ll get into further progress later.
So, I’ve decided to design an Orrery. I’ve been thinking about it for about a month now and I find myself lying in bed awake at night and mumbling orbital characteristics to myself throughout the day. I decided that writing this blog about my experience developing one might help keep my thoughts clear, keep my sanity, and help anyone else who decides to try this. Also, I’ve got to hand it to my wife, who puts up with my endless nonsense in thinking about these things.
First of all, while you likely don’t even know what an Orrery is, you probably have seen one. In simple terms, it’s a mechanical model of our solar system. They are typically constructed of brass, but in my research the last four weeks, I’ve seen them also constructed out of wood, stainless steel, aluminum and other materials. Ancient civilizations such as the Greeks knew how to construct them as early as 150 BC, evidenced by the Antikythera mechanism, discovered in a shipwreck off the coast of Greece in about 1900. Orreries are designed to compute the planetary orbits of our planets around the sun, in a heliocentric model. I’m not going to go into the whole history of Orreries; you can read about them on Wikipedia.
I have always been interested in technologies that as modern day people we seem to have forgotten how to develop. There is evidence worldwide that many ancient civilizations knew how to construct mechanical marvels to handle complex calculations, and an Orrery is one such device. With modern day computers, we seem to have lost the technology to build devices like this, and after investigating it for two weeks, it’s not as simple as it seems. There are not any plans readily available on the internet, and I’ve only found about one company that sells an orrery kit. It appears that maybe plans are available in print form, but again, finding books written in the 1700s may be challenging. One guy built a custom one out of wood, which is very nice, btw. Also, another guy has a really beautiful vertically mounted mechanical clock device, that has similar characteristics to an orrery, but was not quite what I was looking for (but is beautiful nonetheless). In any event, it appears that my orrery will be harder to construct than I first imagined. I just found this great website today that has gearing ratios for the planets that I’m sure will come in handy (more on this later).
Because we are in the modern day of computers, I thought I would design my orrery first on a computer, to get all the sizes and gearpieces accurate. If I make any construction mistakes, they are easily correctable in the virtual world. Also, as I lack any brass machining skills or equipment, if I am unable to ever physically build the orrery, at least I can watch it animated on my PC. Plus, maybe someone will come along with machining skills that can help me out. I happen to have several 3D modeling softwares at home, and the one I decided on is Autodesk 3DS Max. I picked it because not only can you model things in 3D, but also you can animate objects and output video files of the animations. However, I have an older version – 3DS Max 7, and it lacks some of the features of the current version. Also, I have not taken any 3DS Max training or courses on how to use it, and so I have to stumble through the exceedingly complicated user interface. It has tons of features, but I’d be surprised if I know even 5% of them.
Off on somewhat of a tangent here – what initially inspired me to do this was the virtual orrery that appears in the Second Life world Nemo, which btw is absolutely fantastic. Here is the direct link, if you happen to have Second Life installed. I first joined SL because of some online friends who said it was a great gathering place. But, in general, I got rapidly bored with seeing virtual people just standing around in various virtual locations not doing anything. I only recommend Nemo because it is just visually inspiring and highlights many of the types of technologies (in Steampunk fashion) that I’m attempting to capture in developing a device like an orrery. I salute Nemo’s designer, Sextan Shepherd, for this masterful virtual world. BTW, my next favorite device in his world is the Tesla Clock… absolutely stunning!
So, let me synopsize my progress to date now that I’ve started this blog:
I have started the modeling in 3DS Max, and realized quite a few things. Knowing what you don’t know can be pretty daunting to say the least!
First, the actual planet orbits, distances and size are far too great to model to scale. For example, if I place the first four planets (Mercury, Venus, Earth and Mars) within an inch of the Sun in my orrery, the furthest out planet, Neptune, would be nearly 20 inches out (at actual scale). If I also include the dwarf planets Ceres, Pluto, Haumea, Makemake, and Eris, this might go out as far as 64 inches in radius! This would make the planets hard to see and also gearing would be significantly compressed on nearer planets. In addition, for solar system body size, the Sun has nearly 109 diameters that of Earth, while the largest planet, Jupiter, is over 11 times the size that of Earth. I started my model to scale, and realized that it would make for a rather unwieldy and maybe not very nice to look at orrery. Earth looks like a mere dot against the background of the Sun.
Instead, I plan to model all my planet orbital distances and planet/moon equatorial radii based on a Base 10 logarithmic scale. That will make the smaller planets and distances seem larger, and further out planets closer in. Also, I can put a logarithmic scale marks on the planet arms to show actual distance from the Sun. Also, I plan to use a logarithm multiplier so that the planets don’t compress so much that the gearing overlaps each other.
Also, I became concerned with the “look” of the planets in my model. Those of you who have 3DS Max may know that it comes with some Planet textures already for putting on spheres of various sizes (in the tutorials). However, I noticed that the textures have seams and aren’t very nice for 360 degree viewing (or maybe I just don’t understand UVW mapping very well). In any case, I found this website that has some great planetary textures for downloading, including some bump and specular maps for terrain. It even had texture/transparency maps for some of the planets rings, like Saturn and Uranus for example! These look very nice when rendered. I'll post some pics tonight.
I had some challenges figuring out how to map textures to the ring planets Jupiter, Saturn, Uranus, and Neptune. I started with Saturn first and it kept messing up the texture orientation on the model of the ring system. Also, I suppose I’ll have to make some maps for Jupiter and Neptune, based on images from Voyager on Wikipedia. Again, the rings for all four planets also have inner and outer radii that need accurate distance modeling (on a logarithmic scale). Also, I’m assuming at this point that the rings orbit the planets around their hemispheric equator, but I’m not entirely sure. Further, I need to figure out what to do with the “transparency maps” of the rings.
My intent is to convey both orbital revolution around the sun and planetary rotation on its own axis in my orrery. Each planet has its own axial tilt which will have to be modeled, and some even spin in the opposite direction (retrograde), like Venus.
Planetary satellites also become a problem. For more moons, more gearing is required. Jupiter has 63 moons! That would be nearly impossible to develop, and so I’m going to try to limit the maximum number of moons per planet to maybe five of the largest ones. My intent is to pass out two spin speeds on each orrery planet arm (via rotating cylinders), the planet orbit speed and the planet rotation speed. Moon orbital speeds will have to be derived with additional gearing on the end of the arms. Also, I probably won’t model the axial tilt or rotation speeds of satellites, as this would be entirely too much work, except maybe for the Earth’s Moon itself.
Some other things I realized in my first attempt at modeling, was that the orbits of planets are not circular. They are only “roughly” circular, and really follow elliptical paths around the sun. I was using the Semi-Major Axis distance as my distance from the Sun, which could be used if my model was entirely circular, but could be wildly inaccurate for highly eccentric orbits, like that of Mercury. Hence, I had to compile a table of Aphelion and Perihelion distances and consider how to model them. Now, the challenge I am faced with, is that elliptical orbits could be much harder to model mechanical gearing for. Perhaps, it is possible I could use gearing somehow to create a mechanically driven Trammel of Archimedes for my ellipses, but I’m not sure yet.
Additionally, the planetary orbits are not all exactly on the ecliptic plane, each offset slightly by a number of degrees (Mercury, for example is 7 degrees off-axis). Pluto, if I choose to model the dwarf planets, has over 17 degrees of inclination. If I want to accurately represent that, my planet orbits all have to be slightly inclined with respect to the Earth’s rotational orbit (Earth inclination = 0 degrees), and also, they have to be pointed in a particular direction on the orrery, using the angles of the other two axes: the Longitude of the Ascending Node and the Argument of Perihelion.
Also, I just realized today that the planet speed around a given orbit is not a constant velocity. That could present some serious mechanical challenges to say the least. You can see now why using orrery mechanics to model planetary motion are starting to make my head hurt!
Ultimately the goal would be to actually build my orrery, but obviously tools, gears, equipment, and of course cost could prevent that. I figure I’ll just start with the computer generated model and see how it goes. As I’m just sort of outlining my project goals in this post, I’ll get into further progress later.
Wednesday, September 1, 2010
First pictures
Here is an initial render of the the first 4 planets in our solar system, Mercury, Venus, Earth, and Mars:
Note that these planets were designed on a logarithmic scale, and are not depicted actual size. Here is the next four - Jupiter, Saturn, Uranus and Neptune:
In my next post, I'll get into the details of this project so far, and why I would like to undertake such an endeavor.
Note that these planets were designed on a logarithmic scale, and are not depicted actual size. Here is the next four - Jupiter, Saturn, Uranus and Neptune:
I am still not complete with developing the rings for these, and all four planets have ring systems.
Here is a render of an inital arm gearing mechanism I was considering, that ultimately will change in my final model as there are better and more elegant solutions:
In my next post, I'll get into the details of this project so far, and why I would like to undertake such an endeavor.
Intro
I plan to use this blog to describe the process I used to build an orrery. I know that a few other people have attempted this, and lacking any significant experience myself, I thought I'd try it. Some details will be forthcoming, but first a few images...
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