The Celestron NexStar Evolution Series Telescopes is known to be one of the most user-friendly telescopes ever! Celestron engineers designed NexStar Evolution based on years of customer feedback. It offers many thoughtful design features that combine to provide you the best possible experience for beginners and more advanced telescope users alike. One of the best things about this telescope series is that there is no use for external power supply as it is built in. It comes with a lithium-ion battery so that you will be able to enjoy up to 10 hours of star gazing on a single charge. This series also comes with a USB charge port to top off the other devices in your life that need to stay powered on during an observing session.