http://orbitsimulator.com/gravity/beta/GravitySimulatorBeta2008November4.exe There is a feature I introduced a few versions ago, but it was buggy, so I fixed and improved it. It's the "Pointer" feature. To use it, choose menu View > Show Pointer
It allows you to place an arrow on the screen that points to an object of your choosing. When you first display the pointer, it points to the Sun. You can drag it around the screen by dragging the words "To Sun". To change the object it points to, right click the words "To Sun" and a dropdown list will appear that allows you to change the object.
Another change I made is that you can fine-tune the rotation of the rotating frame. As it was, if you were in rotating frame, Pressing "<" or ">" (you had to hold the shift key) rotated the rotating frame by 36 degrees, so 10 presses made a complete circle. Now "<" and ">" shift it by 0.5 degrees, and "." and "," (which are < and > without the shift key) rotate the rotating frame by 36 degrees.
What inspired these fixes is that I wanted to recreate the diagram and trajectory on this page:
http://neo.jpl.nasa.gov/news/2008tc3.html 
(I'm hotlinking their image

)
And here's my effort
To try this yourself, download this simulation
http://orbitsimulator.com/gravity/simulations/2008TC3earthcenteredview.gsim This simulation is in a rotating frame with a very long period (quadrillions of years). This allows you to have basically a non-rotating frame, while giving you the ability to adjust the orientation.
- Run the simulation, and use the "<>,." buttons to rotate the screen until the Sun pointer points straight down. Don't worry if you're not fast enough to do it before the asteroid impacts Earth.
- Pause the simulation
- Re-open the simulation (it should now be the first simulation in the "recently opened" simulations in the File menu.
- Increase the time step to .06
- Unpause the simulation
- Autopilot will pause the simulation for you a few moments before impact, so the screen won't clear on you
- You should now have the same image as above.
With the time step set to .06 seconds, and the graphics update in the Preferences menu set to 15000, you get 1 tick every 15000*.06=900 seconds, or every 15 minutes like the Nasa image.