Resolution. It's Not Just for New Years! 

You and your friend are early for the football game, and your friend decides to play a game with you. To explain the rules, he makes you stand in the end zone and backs away to the 10 yard line. Then he holds up two objects, and asks you to choose which one you want. They are both open pizza boxes But one has a pepperoni pizza in it and the other one is empty. You are very hungry. If you choose the pizza, you get it. But if you choose the empty box, your friend gets the pizza all to himself. Can you tell which is which?

Now your friend backs up to the 100 yard line, and asks you to choose again. Can you still tell which is which? You are a little irritated at your buddy for this trick, when you remember that you have a pair of binoculars in your jacket. You choose the pizza, and your friend can't believe it. From the 100 yard line, he couldn't see your binoculars, but, with them, you could see the pizza!

The binoculars gave you what astronomers call "better resolution".

Now, turn to these three radio telescopes:

 140 Foot Telescope,
140 Feet in diameter
 40 Foot Telescope,
40 Feet in Diameter
Very Large Array Telescope,
22 Miles in Diameter

Predict: Place these is order of increasing resolving power:

1. Lowest resolution


2. Better resolution


3. Best resolution _____________________

Now you are ready to go to HOU.

1.Open two images: CasA-1, and CasA-2. Use your min/max and color palette to adjust both images to your liking.


2. Compare the 2 images. Use the slice tool to learn more. Describe the features you see in each:

 Cas A-1

Cas A-2







3. Predict: Which telescope was used to make each image:


Cas A-1 ______________ Cas A-2 __________________

4. Look in the "Image Info" to see if you were right. ( Hint: 43 meters = 140 feet). Why?

5. Draw Cas A as it might look if the 40 Foot is the telescope used.

6. Try some other objects: Sagittarious A: saga1.fts, saga2.fts and Fornax A: fornax1.fts, fornax2.fts