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De-Coding Starlight: From Pixels to Images - Middle School

#### Student Handout

The Scenario

You and your partner have just discovered a brilliant new supernova remnant using the Chandra X-ray Observatory. The Director of NASA Deep Space Research has heard of your discovery and wants a report of your results in her office in 45 minutes. Unfortunately, your computer crashed fatally while you were creating an awesome image of the supernova remnant from the numerical data. Because the NASA director always wants to see cool images (not numbers) of newly discovered objects, you and your partner will have to create, by hand, an image of the supernova remnant.

To create the image, you and your partner will have to use "raw" data processed from the Chandra satellite. You have tables of the data, but during the excitement of the computer crash, you spilled soda over some of the information and will have to recalculate some values.

In addition to the graph, you and your partner will have to prepare a written explanation of your discovery and answer a few of the Director's questions.

Before you are ready to present your findings to the NASA director, you will need to complete the following three tasks.

1. Your mission is to turn "boring" numbers into a super-cool picture. Before you can make the image, you will need to make some calculations.
2. The raw data for the destroyed "pixels" (grid squares containing a value and color) are listed in Table 1. Before making the image, you will need to fill in the last column of Table 1 by calculating average X-ray intensity for each pixel.
3. After you have determined average pixel values for the destroyed pixels, write the numerical values in the proper box (pixel) of the attached grid. Many of the pixel values are already on the grid, but you have to fill in the blank pixels. This is the grid in which you and your partner will draw the image.

You and your partner will need to complete the following steps in coloring the image. Important Note: Read all the instructions carefully before you start coloring!

1. You are allowed to use five and only five colors in drawing your image.
2. Using colored pencils, shade in the grid using the color legend. Match the value in the grid to the color range shown on the legend and color the grid squares according to the legend.
1. Draw an picture of what the actual supernova remnant would "look" like. In your drawing, include and label the neutron star, a fast outer shock wave, and a slower inner shock wave.
2. The NASA director has the following specific questions about your findings. Answer these questions on the back of the image.
1. In the table, some of the data were missing. In 2-3 sentences, describe how you "handled" these missing data in making your calculations and coloring your image.
2. Because your computer crashed, you had to draw the image by hand. In 2-3 sentences, explain why would it have been easier to use a computer? (In your answer, consider that the Chandra satellite actually sends millions of data from each observation and how long it would take to process millions of data by hand.)

Table 1. "Raw" data of the newly discovered supernova remnant collected from the Chandra X-ray Observatory.

Missing Grid Coordinate Number of X-ray Photons Detected Average Number of Photons
Observation 1 Observation 2 Observation 3 Observation 4 Observation 5
C3 50 54 52 50 54
E8 214 210 210 210 214
F6 148 135 missing missing 130
H10 73 83 missing 80 81
I5 58 69 54 missing 65

Supernova Remnant Image Grid

A B C D E F G H I J K
1 0 1 1 1 1 1 1 1 1 1 1
2 2 5 35 42 48 48 50 51 46 18 7
3 23 36
35 30 27 21 31 38 13 0
4 41 43 24 8 216 155 126 120 54 21 3
5 36 58 37 44 36 20 33 105
23 4
6 32 60 34 106 12
18 96 24 50 17
7 24 65 32 141 41 17 12 126 64 67 21
8 18 69 36 237
146 155 114 22 74 6
9 16 75 38 34 26 12 14 21 77 37 4
10 8 71 63 54 42 23 64
31 16 2
11 3 3 2 1 0 0 2 0 1 0 0

Legend

Average number of photons < 40 40-80 81-120 121-160 >160
Color