Star Radius Calculator
Nope! Stars aren’t measured like lengths using a ruler. And besides, most star are so small (relative to what we see in the sky) and … Read More
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Luminosity Calculator
We think of the Sun as a fixed, yellow ball. Few of us imagine it as a thermonuclear engine. To understand how bright a star … Read More
Flux From Magnitude Calculator
When you look at a star, you see a point of light. You see brightness, but astronomers sees numbers that work backwards. In fact, the … Read More
Brightness Ratio Calculator
Here’s an example: Two stars are visible next to each other in the sky. One shines brightly; the other barely flickers. You instantly notice the … Read More
Absolute Magnitude Calculator
If we put Sirius at same distance as us (ten parsecs), then it would of been over twenty times as bright than our own sun. … Read More
Apparent Magnitude Calculator
If you look out at a dark hillside, you may see lots of stars twinkling, but your eyes will not reveal there true nature. Each … Read More
Distance Modulus Calculator
Distance modulus allows you to figure out the distance to some distant bright thing in the night sky. It’s a way of working around astronomy’s … Read More
Parallax to Distance Calculator
The best immediate measurement is parallax. On a clear night, go outside. Look up into the sky. The stars appears unchanging and ancient. But it’s … Read More
Parsec to Light Year Converter
The parsec is a measure of distance. It’s not a measure of speed. In fact, you might have seen people quote that they’re going at … Read More
Astronomical Unit Converter
Astronomical units are a special type of unit. The International Astronomical Union has defined it exactly as 149,597,870,700 meters, and that number doesn’t change. This … Read More