Observing Basics: Distances in Space

Light travels at a constant speed of 299,702,458 meters per second (186,282 miles per second). That's equal to more than 670 million mph (1.08 billion km/hr). So the distance light travels in a year is known as the light-year, and it's equivalent to 5.88 trillion miles (9.46 trillion km).

Expand your observing at Astronomy.com

StarDome
Check out Astronomy.com's interactive StarDome to see an accurate of your sky. This tool will help you locate this week's targets.

Intro to the Sky: Get to know the night sky
Learn how to use star charts, find constellations, and observe the brightest objects in your night sky with in this handy reference section.

The Sky this Week
Get aÒšdaily digest of celestial events coming soon to a sky near you.

Observing Talk
After you listen to the podcast and try to find the objects, be sure to share your observing experience with us by leaving a comment at the blog or in the Reader Forums.

Other Observing Basics videos

• Buying Binoculars
• Visual Solar Filters
• Eyepieces
• Finder Scopes