Note: use a mouse instead of a trackpad or touchscreen to limit frustration while using Afterglow. 

Click “Next” above to see the step-by-step instructions.

Alternate Format: Video Instructions

• Follow along with the tutorial.

Alternate Format: Written Instructions

1. Set the brightness and contrast levels to “Bright Target” so the object is not washed out.
2. Click on the “plotter” icon shaped like a line.
3. Click on one side of the planet. Let go of the mouse button.
4. Click on the other side of the planet. Let go of the mouse button.
5. Scroll down a little in the plotter panel and record the angular diameter to the nearest 0.1 arcseconds
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6. Note: For Saturn, measure the angular diameter of the disk/face of the planet, NOT the rings.
7. Note: If the object’s phase is not full, it will not appear circular. If so, measure its angular diameter along its longer axis.
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