By Ocean Malandra – Updated Aug 30, 2022

Celestron offers a broad range of telescopes, from entry‑level models like the “Firstscope” to advanced equipment used by seasoned astronomers. While the underlying design principles are consistent across the lineup, new users may still find the initial setup a bit daunting. This guide walks you through the essential steps to get your Celestron telescope up and running with confidence.

Step 1 – Install an Eyepiece

Eyepieces determine the magnification and field of view. Select an eyepiece that matches your observing goal. Unscrew the thumb screws on the focuser’s outer ring, slide in the eyepiece, and tighten the screws to secure it.

Step 2 – Aim the Telescope

To move the mount, loosen the base lock nut. Gently point the telescope toward your target and then retighten the nut to lock the direction in place.

Step 3 – Focus

With the telescope aimed, look through the eyepiece. Turn the focusing knob located just below the eyepiece: clockwise increases magnification (moves the focus farther), counter‑clockwise brings it closer.

Step 4 – Adjust Magnification

Once focused, change magnification by swapping eyepieces. Magnification is calculated by dividing the telescope’s focal length by the eyepiece focal length. For example, a 400 mm telescope with a 20 mm eyepiece yields 20× magnification.

Step 5 – Determine the Field of View

To understand how much of the sky you’re seeing, calculate the field of view: divide the eyepiece’s apparent field (printed on the side) by the current magnification. The result is expressed in degrees and helps gauge the size of the object you’re observing.