Accuracy in WWT

Hi, it is a great software and i use it in many ways
but there are problems too
on 2019.06.22 asteroid “2019 MO” had a soft collide with Earth
in the image that i attached you see that during impact there are about 2LD difference between Earth and asteroid position. i know that for this kind of approaches most recent elements is needed but i don’t think it solves the matter too

often import of new elements in this software is not too easy and there must be an uncertainty with planet coordinates instead of it
Hope that solve of these inaccuracies make the software more valuable in such a cases

Another Example: Today asteroid 2019 MB4
closest approach 0.82LD 7:20’UTC
with right elements it must be almost above North pole during closest approch
but as you see in image it is behind Moon and Earth orbit

Hmmm … Well, I can reproduce your results with 2019 MB4.

Under the hood, it looks like WWT is downloading data from the Minor Planet Center then converting it to a temporary custom TLE format. So the orbital data should be fresh, but I could imagine that we might lose precision in the conversion. @astrojonathan would be the one to know for sure.

There are two things that effect the accuracy.

  1. The MPC data needs a fresh download to get the best accuracy. Is this the Windows or Web Client?
  2. To calculate almost 700,000 objects 60 times a second we need to use Floats in the GPU, doubles are not an option. This fundementally limits us to much less precision than the planetary and moon computation. WWT should not be used to see if a MPC object might collide with Earth or to specifically spot a RA/DEC of a nearby object.
  3. When you create a new reference frame from an MPC objects it captures those orbital elements at the creation time. Those are simple orbital elements and we don’t do the multi-body simulation required to get really accurate tracks for things that come really close to planetary bodies. The MPC creates updates to get estimated paths, but they are not close enough for detailed study.

The MPC and orbital features are designed for visualization and not accurate simulation, that is why we don’t show any derived calculations from MPC orbits.

Hi All, that image was in windows version.with WebClient (in win7) object is near Mars orbit that must be a bug
this image is correct position of 2019 MB4 at its closest approach,Jul 09

at 0.82LD orbit don’t change too much so we don’t need very recent elements
it happened for 2019 NN3 after it too and planet was further than object again.
more than asteroid orbit i am suspected to planets themselves
Coordinate of some main planets in WWT isn’t compatible with real images and planetarium softwares like Stellarium. you can check for far planets there are some arcmins difference that for a near Planet like Earth it can be one LD or more…

Look at this sample again, Today(2019-09-07) NEO, 2019RC1 must pass about half LD below the Earth at 10:48’ UTC
you see that at 10:48’ UTC asteroid is about 2LD and Earth is ahead. in Webclient it is farther than Mars. i think it is the same issue that repeat frequently


I tried to compare March Equinox in both WWT & Stellarium

March20, 2019 Equinox was at 21:58’ UTC

In Stellarium with Ecliptic grid(J2000) Sun is tangent with Right ascension line zero, but in WWT it is in center of zero gridlines (may it’s not J2000 system)

It takes about 6.5 hours more till Sun reach to center of the gridlines in Stellarium

as Earth orbital velocity is about 30km/s it moves about 700,000km during this 6.5 hours that may it can cause about 1.8LD inaccuracy in close approachs