To experiment with images that have been digitized and understand the size of the images used by KAO observers.
Distribute newspaper photographs to the class. Ask students to look carefully at the photographs with a magnifying lens and then describe what they see.
Explain that modern astronomical images are much like newspaper photos. They are made of tiny dots of information called pixels, or "picture elements". Pixels seen in close-up are tiny squares of different brightnesses or colors.
Procedure Distribute the activity sheet and read the material along with the students. Discuss the different images and how they look from different distances. The "blocky" image close to the top left of the page is part of the "S" from NASA--which can be more easily recognized by stepping back.
Remind students that KAO images generated by the detector flown during the LFS missions are only 8 pixels by 8 pixels, generated by an array of 8 x 8 detectors with the 4 corners open, leaving 64 - 4, or 60, pixels in each image. Ask students to describe what kind of picture can be drawn with this few pixels. Challenge students to create an 8 pixel by 8 pixel drawing that someone else can interpret. Use the graph paper for this project. Each block (pixel) must be just one color or shade of gray.
Computer monitors also use pixels. In the Control Panels for most computers you should find an option to change screen resolution. Experiment with these monitor settings to reinforce the concept of different pixel values.
In reality, the KAO does not take pictures in the sense that we use a 35mm still camera to "take" a photograph. Instead it collects infrared brightness levels: astronomer Al Harper says it's rather like pointing 60 thermometers at an object to take its temperature. Students should be aware that they'll be looking for brightness levels, revealing clues to the objects being studied, rather than pictures like those from the Hubble Space Telescope's visible light cameras.
To understand field sizes for different images at different wavelengths.
If possible bring in a still or video camera. Let students look through the viewer and notice that a traditional camera has a set field of view. Ask students what they can do to make the field of view larger: move away or change lenses.
Procedure Read the "Sizing up the Field" section as a class. Suggest students choose which areas of M33 they would most like to observe. Discuss as a class. Remind them what they've learned in previous activities about how areas that are bright in the infrared might look like in visible light.
This activity works well on an overhead projector. Make a transparency by enlarging the galaxy image onto a transparency. Have students in teams of two or three research and verbally present rationales for looking at M33 in various places.
Create "viewing windows" for the detector's other possible field sizes as a math activity. If the box shown on the photograph on the Activity is 2 arc minutes x 2 arc minutes, then a 6 arc minute box would be three times wider and three times higher than the box shown. (see glossary for "arc minutes" etc.)
Students at certain of the live video uplink sites, including
the Adler Planetarium in Chicago, will assist the KAO astronomers
in pointing the detector via computer commands over the Internet
during the flight, as a demonstration of what's called "telescience".
They'll have to work with field size in just the same way your
students did in this activity.