A 3-star alignment on a Celestron NexStar telescope helps improve the accuracy of the telescope's tracking and GoTo capabilities.

Here's a step-by-step guide to completing a 3-star alignment:
Set up your telescope: Place your telescope on a level surface, and make sure it is properly balanced. Extend the tripod legs and secure them.
Attach the telescope: Mount the telescope on the tripod, making sure it is properly secured.
Align the finder scope: In daylight, aim the telescope at a distant object (e.g., a tree or building) and center it in the eyepiece. Then adjust the finder scope until the object is centered in its view.
Power on and enter your location: Turn on the telescope and enter the date, time, and location (longitude and latitude) if prompted. This information helps the telescope determine the position of celestial objects.
Point the telescope north: Set your telescope to its home position by pointing it towards the North Celestial Pole (NCP). For observers in the Northern Hemisphere, this is approximately towards Polaris (the North Star). The telescope should be level and with the optical tube parallel to the ground.
Select 3-star alignment: On the hand control, navigate to the alignment menu and select the "3-Star Align" option.
Choose the first alignment star: The hand control will suggest a list of bright stars that are currently visible. Choose one and press "ENTER". The telescope will automatically slew (move) toward the approximate position of the selected star.
Center the first alignment star: Look through the eyepiece and use the hand control's arrow buttons to center the selected star in the eyepiece. Once centered, press "ALIGN" or "ENTER".
Choose the second and third alignment stars: Repeat steps 7 and 8 for two more stars, making sure to choose stars that are well-separated from each other and from the first star. This helps improve the accuracy of the alignment.
Complete the alignment: After aligning on the third star, the hand control will display a message indicating that the 3-star alignment is complete. Your Celestron NexStar telescope is now ready for accurate tracking and GoTo functionality.
Remember that practice makes perfect, and you may need to repeat the process a few times to get the hang of it. With experience, you'll be able to perform a 3-star alignment quickly and efficiently. Happy stargazing!