5 ms·

I suspect the gap is at least 50% rendering artifact, but all 1.4M asteroids are plotted as (small) fraction of its orbital ellipse, so the density distribution

I suspect the gap is at least 50% rendering artifact, but all 1.4M asteroids are plotted as (small) fraction of its orbital ellipse, so the density distribution is reflective of the real data (more specifically, orbit types)

slg 2y ago
If I understand both the code and o11c's comment correctly, it sounds like the difference is less rendering artifact rather than what is being rendered. This code is rendering the asteroids based off their semi-major axis, but Wikipedia appears to be rendering their actual positions at a specific moment in time with the asteroids all at various points in their eccentric orbit.
- d_silin 2y ago
  I am pretty sure it is the opposite :)
  - slg 2y ago
    Care to expand on that? Wikipedia image has the Greeks ahead of Jupiter and the Trojans behind Jupiter. Doesn't that clearly show it is an image of a moment in time? And the only attributes of an asteroid this code[1] seems to use are the eccentricity, semi-major axis, and perihelion. Although I'm no expert in either Python or astrophysics so I may be missing something. [1] - https://github.com/DarkStar1982/Orbidium/blob/536afc2e12e9a25ce3288c882bcaca83ef8af15c/pages/static/canvas.js#L54 https://github.com/DarkStar1982/Orbidium/blob/536afc2e12e9a2...
    - d_silin 2y ago
      The code draws full orbit ellipse if selected to do so, but the original picture was rendered using a different mode, where just a small slice of the orbit arc is rendered, pretty much showing an instantaneous position of asteroid. Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc, should be actual position of the asteroid) but MPC file doesn't provide this information - you need ephemeris from here: https://www.minorplanetcenter.net/iau/MPEph/MPEph.html https://www.minorplanetcenter.net/iau/MPEph/MPEph.html After all, it is mostly a data visualization demo (although I tried to be precise with scale too)
      - slg 2y ago
        >Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc That sounds to me just like a rephrasing of what I originally said. The locations in the Wikipedia image are correct relative to each other (because it is representing a moment in time) while the locations from the code are not correct relative to each other and are instead "the same position on ellipse arc" (although maybe I was wrong with my assumption that the "same position" was at the semi-major axis).
        d_silin 2y ago
        Yeah, I changed the orbit position to randomly sampling orbit locations and asteroid belt gaps are definitely rendering artifacts.
        slg 2y ago
        Lol, I thought our confusion was over astrophysics and not English. The gaps are a real physical phenomenon that may or may not be visible depending on rendering decisions. I wouldn't consider them a "rendering artifact" as I take that to imply the artifact was artificially created by the rendering. Either way, thanks for answering my questions!

slg 2y ago

If I understand both the code and o11c's comment correctly, it sounds like the difference is less rendering artifact rather than what is being rendered. This code is rendering the asteroids based off their semi-major axis, but Wikipedia appears to be rendering their actual positions at a specific moment in time with the asteroids all at various points in their eccentric orbit.

d_silin 2y ago
I am pretty sure it is the opposite :)
- slg 2y ago
  Care to expand on that? Wikipedia image has the Greeks ahead of Jupiter and the Trojans behind Jupiter. Doesn't that clearly show it is an image of a moment in time? And the only attributes of an asteroid this code[1] seems to use are the eccentricity, semi-major axis, and perihelion. Although I'm no expert in either Python or astrophysics so I may be missing something. [1] - https://github.com/DarkStar1982/Orbidium/blob/536afc2e12e9a25ce3288c882bcaca83ef8af15c/pages/static/canvas.js#L54 https://github.com/DarkStar1982/Orbidium/blob/536afc2e12e9a2...
  - d_silin 2y ago
    The code draws full orbit ellipse if selected to do so, but the original picture was rendered using a different mode, where just a small slice of the orbit arc is rendered, pretty much showing an instantaneous position of asteroid. Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc, should be actual position of the asteroid) but MPC file doesn't provide this information - you need ephemeris from here: https://www.minorplanetcenter.net/iau/MPEph/MPEph.html https://www.minorplanetcenter.net/iau/MPEph/MPEph.html After all, it is mostly a data visualization demo (although I tried to be precise with scale too)
    - slg 2y ago
      >Now, I am pretty sure actual positions are not correct relative to each other (it is the same position on ellipse arc That sounds to me just like a rephrasing of what I originally said. The locations in the Wikipedia image are correct relative to each other (because it is representing a moment in time) while the locations from the code are not correct relative to each other and are instead "the same position on ellipse arc" (although maybe I was wrong with my assumption that the "same position" was at the semi-major axis).
      - d_silin 2y ago
        Yeah, I changed the orbit position to randomly sampling orbit locations and asteroid belt gaps are definitely rendering artifacts.
        slg 2y ago
        Lol, I thought our confusion was over astrophysics and not English. The gaps are a real physical phenomenon that may or may not be visible depending on rendering decisions. I wouldn't consider them a "rendering artifact" as I take that to imply the artifact was artificially created by the rendering. Either way, thanks for answering my questions!