An Application Of The Parallax Effect (Page 2 of 2) in pdf

An Application Of The Parallax Effect Page 2

Answer Key

Problem 1: With a millimeter ruler, determine the scale of each image in km/mm. How

many kilometers did AR978 shift from the center position (SOHO location for AR) between

the two STEREO images? This is the measure of 'L' in the diagram.

Answer:

STEREO-Left image, sun diameter = 28 mm, actual = 1,392,000 km, so the scale is

1392000 km / 28mm = 49,700 km/mm

SOHO-center sun diameter = 36 mm, so the scale is

1392000 km/36mm = 38,700 km/mm

STEREO-right sun diameter = 29 mm, so the scale is

1392000 km / 29 mm = 48,000 km/mm

Taking the location of the SOHO image for AR978 as the reference, the left-hand image

shows that AR978 is about 5 mm to the right of the SOHO location which equals 5 mm x

49,700 km/mm = 248,000 km. From the right-hand STEREO image, we see that AR978 is

about 5 mm to the left of the SOHO position or 5 mm x 48,000 km/mm = 240,000 km.

The average is 244,000 kilometers.

Problem 2: Using the Pythagorean Theorem, determine the equation for the height, h, in

terms of R and L.

Answer:

( R + h)

= R

+ L

1/2

= ( R

+ L

)

- R

Problem 3: How high (h) above the sun's surface, called the photosphere, was the AR978

viewed by STEREO and SOHO on December 12, 2007?

1/2

Answer:

( (244,000)

+ (696,000)

)

696,000

737,500 - 696,000

41,500 kilometers

Space Math

An Application Of The Parallax Effect Page 2