Lesson Six: How to Find A.M.E Components

Previously wizards relied on magical tools to find A.M.E components. These tools can do much more than their muggle counerparts. Especially because the first non-magical telescope was on invented in 1608, 70 years after von Rheticus. The von Rhetics has as much resolving power as a 12cm muggle telescope (1 arcsecond).

Now though muggle telescopes are far superior. They can measure angular size, phase, optical albedo, and the distance from the sun more accurately. The Hubble has 20 times as much resolving power as the von Rhetics. The ground-based Keck telescope uses adaptive optics. A laser beam is used for the aformentioned adaptive optics. Air movement makes the beam and nearby stars appear to wobble but the primary mirror which follows the beam adjusts by bending to cancel the wobbling of the beam and therefore the nearby stars as well.

After Dr. Mansour published her work on A.M.E new improvments have been made to the von Rhetics.

Distance From the Sun

Von Rheticus studied planet motion and calculated their distance from the Sun. He was the first to see Uranus and Neptune through his telescope. He rigged his telescope to recognise planets from its reflected magic and entered into his telescope the distance of each planet from the Sun. He used Earth's distance for the moon. Like Copernicus he assumed planets orbit the Sun in a circle, though they actually move in a ellipse, meaning the distance isn't always constant. This meant his distances were averages not the current distance. The average is usually fine for calculating A.M.E except for Mars and Mercury. Isaac Newton made a way to calculate the exact distance from the sun.

Angular Size, Phase and Optical Albedo

We often use muggle calculations for these as they have more accurate equipment. Albedo is constant but the angular size depends how far it is from Earth. Venus has the widest angular size range appearing 6.8 times as large closer to Earth than it does further away. 

Refer to the table in the lesson for all albedo and angular size of celestial bodies.

The von Rhetics has a way of coming up with the values. The two buttons at the top of the wider tube, a placement chosen so that pressing them would not jar the telescope, are used. 

The "S" button is for angular size, the angular size of the object your looking at will appear in pure red characters.

If the object is too large to see in the lens holding down the button from one end to the other of the object will scan the object and calculate the angular size. 

The von Rhetics calculates phase by measuring its angular length and width and diving the width by the length. This is the true value if none of the light of the object is blocked. The formula for otherwise is too complicated for the telescope. 

The other button on the telescope "A" stands for Albedo. It calculates to optical albedo of the object. The value will appear in red numbers for as long as the button is pressed. You will see the average albedo for whatever part of the object is in view. 

The von Rhetics calculates albedo by identifying a familiar celestial object by reflected magic. It uses the information it has about distance from the Sun (average), its angular size, phase, and the amount of light it relfects to Earth. It calculates the albedo from the formula in the lesson.

The calculated value is only a good estimate if the bosy is familiar. We now have access to the more accurate albedo's the muggles have measured. 

Interference and Magical Albedo

To calculate interference, measure the angular seperation between the target and other objects in the sky. You need the relative strength of the magic reflected by the other bodies compared to the target as well.

To calculate magical albedo from optical albedo you need to know what the surface is made of. Dr. Mansour discovered that most magical and optical albedo's are the same however, rocky surfaces tend to reflect only half as much magic as light and water (including ice) cuts it in half again (1/4) as it tames and absorbs Sun's magic.

Calculating the amount of magic reflected to Earth is complicated and approximate. Fortunately, the modified von Rhetics detects the amount of magic coming from a celestial object when pressing "A. This means t displays the A.M.E Quotient in pure red light.