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   Which bright object is asteroid Hildrun?
These images were taken 15 minutes apart. Of the three bright objects, two are stars and one is an asteroid. How can we find the asteroid? Decide which one you think is asteroid Hildrun.   Try drawing and measuring with the slice tool. The distances between stars won't change; the distances between a star and an asteroid  will change.

Adding or Subtracting Images to Find Asteroids!

1. Open the HOU image processing program.
2. Open both images of one of the asteroids, for example, Hildrun1.fts and Hildrun2.fts.
3. Click on Hildrun1.fts. Go to Manipulation, then Add (or Subtract).
4. Click on Displayed Image. With the down arrow, choose Hildrun2.fts. Click on Display result in a new window. Click OK.
5. View your results. Do you see an object with a double position?  Is this the object you thought was the asteroid?

Which bright object is asteroid Ryokan?
These images were also taken 15 minutes apart. Most of the bright objects are stars. One is asteroid Ryokan! Which one do you think is asteroid Ryokan? Explain your reasons and methods of analysis.

Looking for asteroids in our starry sky!

• Asteroids are made of rock and metals like iron and nickel.  They are part of our Solar System.  They reflect sunlight and orbit the Sun, like planets and moons.   Asteroids are much smaller than most moons and planets.
• Asteroids change position in our starry sky as they orbit the Sun. Since they are part of our own Solar System, they are closer to us than the background stars. Our Earth also orbits the Sun and rotates on its axis. We observe asteroids from a  rotating, orbiting planet Earth! All these motions combine to shift the positions of the asteroids in these images.
• The stars in these images look bright and small. Stars look bright because emit light from the nuclear fusion happening in their cores. These stars are really huge but they look small because they are very very far away.

After you have tried adding or subtracting the asteroid images, check your results!

HOU Educators:  Download these .fts Asteroid Images.  The images of Hildrun and Ryokan were taken for HOU with the 3.5 meter telescope at Apache Point Observatory in New Mexico from the Adler Planetarium & Astronomy Museum by University of Chicago Astronomer, Dave Cole.

01/28/2000

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