Apparent Magnitude

Apparent Magnitude Photo Credit: Clipart.com


Your teacher has introduced you to apparent magnitude, luminosity, and distance of stars. Now your teacher will help guide you through the use of the GoSkyWatch Planetarium app, which can help you figure out those things about stars.

Using the GoSkyWatch Planetarium App

Take some time to explore the GoSkyWatch Planetarium app on your mobile device. There is a red icon at each of the four corners of the app. The heart icon at the bottom left is for sharing via social media, which should be turned off on classroom devices. The clock icon on the bottom right refers to the date and time; this setting should already be set.

The magnifying lens icon on the top left opens to reveal five additional icons in red circles. The planet icon allows you to find and learn more about the sun, moon, and planets in our solar system. When any one is selected, the app will locate it using four blinking pointers. The Cassiopeia icon allows you to learn more about and identify the visible constellations. The galaxy icon allows you to search for Deep Sky Objects. The star icon allows you to search for any visible star by name, distance from Earth, or magnitude. Finally, you will notice a birthday cake slice icon, which allows you to set your birth date. The stars are then organized by how old you were when the light that you currently see was emitted from the star. If the light originated before you were born, the date of its origin is shown.

The gears icon on the right opens up to three icons and one vertical bar. The vertical-line bar allows you to set the brightness of the night sky, making more or fewer stars visible. It is a helpful tool to show what the night sky would look like without any pollution or barriers. The wrench icon allows you to turn display effects off or on. For example, visualization of the Milky Way can be turned off or on, depending on what is actually visible in the night sky. If you are looking at the sky at night with the app, the Night Mode feature will switch to red lighting, preserving your night vision. 

Finding Apparent Magnitude Activity

Now, use the app to find the Little Dipper, which is listed as Ursa Minor. Looking at the image of the Little Dipper that your teacher has provided you, record the apparent magnitude and distance of each of the seven major stars in the chart on this sheet. This can be done by moving the small circular icon in the display over each of the stars. The apparent magnitude is indicated by a star symbol under the name of the star. 

Name of Star in Little Dipper

Apparent Magnitude








Epsilon Ursae Minoris


Zeta Ursae Minoris



Eta Ursae Minoris











Of the seven stars, which one is the brightest? 

How do we know? 

Which star is actually the closest to us? 

Which star is the furthest? 

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