De-Coding Starlight: From Pixels to Images - High 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.

Your Tasks

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

Task A: Calculations

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.

Task B: Coloring 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. Each of the five colors will represent a range of intensity values. You and your partner should select the range of intensities assigned to each color. Fill in these range values and associated colors on the legend at the bottom of the image grid sheet.
3. Hint: as you assign colors to ranges, it is best to pick colors that are "close" to each other as you move from one range to another. For example, in the range with the lowest intensities you may assign the color red. In the next lowest range, you would then assign the color orange, rather than indigo. Before proceeding, have the instructor check you assigned colors.
4. Using colored pencils, shade in the grid using your color legend.

Task C: Preparing the Presentation

1. On the back of the image, write a detailed description (1-2 paragraphs) of the prominent features of the supernova remnant. Be sure to describe how the image shows a neutron star, a fast outer shock wave, and a slower inner shock wave.
2. Include an artist's impression drawing of what the actual supernova remnant would "look" like.
3. 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 3-4 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 3-4 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
A4	39	40	40	42	42
B6	59	61	62	60	58
B7	62	71	missing	63	missing
B8	64	68	71	71	72
C3	50	54	52	50	54
C6	33	missing	missing	31	38
C10	64	63	61	64	missing
D2	41	missing	missing	missing	43
D6	104	missing	105	108	108
D7	140	144	142	141	137
D10	62	50	57	50	52
E7	41	43	43	36	40
E8	214	210	210	210	214
F2	missing	49	49	47	47
F4	153	missing	154	155	156
F6	148	135	missing	missing	130
F8	152	141	147	145	144
G2	49	51	48	50	missing
G4	130	123	missing	missing	124
H2	51	49	53	50	50
H3	34	25	38	31	26
H4	115	114	missing	128	123
H6	95	97	missing	missing	missing
H8	115	115	115	113	112
H10	73	83	missing	80	81
I3	missing	39	35	37	42
I5	58	69	54	missing	65
I9	68	77	80	81	missing
J6	46	49	55	missing	48
J7	61	69	79	74	54

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		48				46	18	7
3	23	36		35	30	27	21			13	0
4		43	24	8	216				54	21	3
5	36	58	37	44	36	20	33	105		23	4
6	32				12		18		24		17
7	24		32			17	12	126	64		21
8	18		36	237			155		22	74	6
9	16	75	38	34	26	12	14	21		37	4
10	8	71			42	23	64		31	16	2
11	3	3	2	1	0	0	2	0	1	0	0

Legend

Average number of photons
Color