Asteroid Apophis in 2029, charting

Just for fun, I was entering the orbital elements of asteroid Apophis into
my Starry Night astronomy program.

I got them from JPL's website:

Orbit: Near-Circular Reference Plane: Ecliptic 2000
Mean Distance (a) (in AU) 0.922261415
Eccentricity (e) 0.191059415
Inclination (i) 3.331314642
Ascending Node 204.4591523
Arg of Pericenter 126.3855713
Mean Anomaly (L) 307.3630785
Epoch (Julian Date) 2454200.5

Then I fast-forwarded to around April 13th, 2029, when the asteroid is going
to come within spitting distance of Earth (inside the orbit of geosychronous
satellites).

In my simulation, it came to its closest approach to Earth on April 14th,
2029, around 13:00 UT, so one day late.

And the nearest it got to Earth seemed to be around 2.6 million miles,
rather than the 22,000 miles or so it should have been at, so off by roughly
a factor of 100.

Still, fairly impressive for calculating 22 years in the future.

But I was wondering if I've simply reached the limits of my Starry Night
program to calculate it, or if, with slightly more accurate numbers, I could
place it closer to where it's supposed to be on that date.

So....anyone have better numbers than the above for Apophis?

(Again, I'm assuming that JPL's numbers are about the best there is and my
astronomy program is just taxed beyond its limits to really place the
asteroid exactly where/when it would be, but, if anyone can prove me wrong,
I'd appreciate it).

On Aug 8, 11:38 am, "algomeysa2"
wrote:
Just for fun, I was entering the orbital elements of asteroid Apophis into
my Starry Night astronomy program.

I got them from JPL's website:

Orbit: Near-Circular Reference Plane: Ecliptic 2000
Mean Distance (a) (in AU) 0.922261415
Eccentricity (e) 0.191059415
Inclination (i) 3.331314642
Ascending Node 204.4591523
Arg of Pericenter 126.3855713
Mean Anomaly (L) 307.3630785
Epoch (Julian Date) 2454200.5

Then I fast-forwarded to around April 13th, 2029, when the asteroid is going
to come within spitting distance of Earth (inside the orbit of geosychronous
satellites).

In my simulation, it came to its closest approach to Earth on April 14th,
2029, around 13:00 UT, so one day late.

And the nearest it got to Earth seemed to be around 2.6 million miles,
rather than the 22,000 miles or so it should have been at, so off by roughly
a factor of 100.

Still, fairly impressive for calculating 22 years in the future.

But I was wondering if I've simply reached the limits of my Starry Night
program to calculate it, or if, with slightly more accurate numbers, I could
place it closer to where it's supposed to be on that date.

So....anyone have better numbers than the above for Apophis?

(Again, I'm assuming that JPL's numbers are about the best there is and my
astronomy program is just taxed beyond its limits to really place the
asteroid exactly where/when it would be, but, if anyone can prove me wrong,
I'd appreciate it).


Perhaps your program isn't taking into account Apophis's gravitational
interaction with the Earth.

Double-A

"Double-A" wrote in message ups.com...

Perhaps your program isn't taking into account Apophis's gravitational
interaction with the Earth.

And other celestial bodies.

"algomeysa2" wrote in
:

Just for fun, I was entering the orbital elements of asteroid Apophis
into my Starry Night astronomy program.

I got them from JPL's website:

Orbit: Near-Circular Reference Plane: Ecliptic 2000
Mean Distance (a) (in AU) 0.922261415
Eccentricity (e) 0.191059415
Inclination (i) 3.331314642
Ascending Node 204.4591523
Arg of Pericenter 126.3855713
Mean Anomaly (L) 307.3630785
Epoch (Julian Date) 2454200.5

Then I fast-forwarded to around April 13th, 2029, when the asteroid is
going to come within spitting distance of Earth (inside the orbit of
geosychronous satellites).

In my simulation, it came to its closest approach to Earth on April
14th, 2029, around 13:00 UT, so one day late.

And the nearest it got to Earth seemed to be around 2.6 million miles,
rather than the 22,000 miles or so it should have been at, so off by
roughly a factor of 100.

Still, fairly impressive for calculating 22 years in the future.

But I was wondering if I've simply reached the limits of my Starry Night
program to calculate it, or if, with slightly more accurate numbers, I
could place it closer to where it's supposed to be on that date.

So....anyone have better numbers than the above for Apophis?

(Again, I'm assuming that JPL's numbers are about the best there is and
my astronomy program is just taxed beyond its limits to really place the
asteroid exactly where/when it would be, but, if anyone can prove me
wrong, I'd appreciate it).



The above orbital elements are fixed numbers which assume that the orbit
will remain unchanged indefinitely. This is of course not the case, as the
orbit is perturbed by the gravity of the planets. You need to do a full
simulation to get an accurate result. Even then, the uncertainty in the
initial data results in increasing error over time between the calculations
and reality.

Klamzon.