An Application Of The Parallax Effect printable pdf download

An Application Of The Parallax Effect

An Application of the Parallax Effect

Two NASA, STEREO satellites take images of the sun and its surroundings from two

separate vantage points along Earth's orbit. From these two locations, one located ahead of

the Earth, and the other located behind the Earth along its orbit, they can create stereo images

of the 3-dimensional locations of coronal mass ejections (CMEs) and storms on or near the

solar surface.

The three images below, taken on December 12, 2007, combine the data from the two

STEREO satellites (left and right) taken from these two locations, with the single image taken

by the SOHO satellite located half-way between the two STEREO satellites (middle). Notice

that there is a large storm event, called Active Region 978, located on the sun. The changing

location of AR978 with respect to the SOHO image shows the perspective change seen from

the STEREO satellites. You can experience the same Parallax Effect by holding your thumb at

arms length, and looking at it, first with the left eye, then with the right eye. The location of your

thumb will shift in relation to background objects in the room.

The diagram to the right shows

the relevant parallax geometry for the two

satellites A and B, separated by an angle

of 42 degrees as seen from the sun. The

diagram lengths are not drawn to scale.

The radius of the sun is 696,000 km.

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 average

measure of 'L' in the diagram.

Problem 2: Using the Pythagorean

Theorem, determine the equation for the

height, h, in terms of R and L. Assume

the relevant triangle is a right triangle.

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?

Space Math

An Application Of The Parallax Effect