When you look up at the night sky, have you ever wondered why some stars are brighter than others?

This project will teach you how to build a scaled model to understand the relation between brightness(magnitude), distance and luminosity.

Astronomers define star brightness in terms of apparent Magnitude, which depends on:

Luminosity: how bright it is physically.
Distance: how far away it is from the earth.

In this model, a LED represents an individual "Star", the brightness and position can be varied. On the "Earth" side, there is an ambient light sensor to get the light intensity, and an ultrasonic sensor to detect the distance. The model connects to a microcontroller then visualize the data in Mind+.

Supplies

1 Wide Cardboard Box

1 Cardboard Sheet

1 Straw

1 Bottle Cap

2 Wires

1 Arduino Uno with Extension Shield

1 Ultrasonic Sensor

1 Ambient Light Sensor

1 LED

220Ω Resisitor

Step 1: Make the Base

Use the box to make the base.

Step 2: Make the Slider and Fix the Sensors

Make the slider with straw and led, then fix the sensors.

Step 3: Connect Hardwares

Connect sensors and led to the Arduino.

Step 4: Brightness-Distance Relationship

When the star's luminosity is fixed, we can study how the brightness of a star changes with distance by gently moving the LED and seeing the data visualize simultaneously in Mind+.

Step 5: The Big Dipper Magnitude

Once you get the distance and luminosity data of the stars, you can set the star parameters and measure their magnitude.

1) Move the LED to match the dist with the star distance/10 rounded down (eg: Merak 79 - dist 7).

2) Press keyboard 1-7 to set the luminosity and get the magnitude for each star

3) Compare the graph