[RobRoy]

Wow! You are right. It did not specifically say that none of the spectrum was visible to the naked eye.

I usually nail other people for making these kind of assumptions and you nailed me! Good job!

Now I have to kill you.... 8^>

[Flyer]

At least have the decency to send flowers to my funeral.

[RadioAstronomer]

An interesting item of note is that the constellations we see are made up of the brightest stars. Even in the same constellation these stars are at different distances from the Earth. Some may be dimmer than the others, however, being closer they are just as bright as a larger one further away. The brightness of a star is called its magnitude. There are two ways astronomers measure magnitude: Apparent Magnitude and Absolute Magnitude.

The Apparent Magnitude is how bright a star appears to us here on the Earth. The Absolute Magnitude is how bright a star would appear if it were exactly ten parsecs away from the Earth. (Close to 33 light years).

Two notes:

1) Apparent magnitude is usually denoted with a small “m” and absolute magnitude uses a capital “M”.

2) The magnitude scale is backwards of what you might think, the larger the number the fainter the object.