Celestron CrossAim Reticle Eyepiece: Aligning and Finding Objects

By TelescopesPlus - The #1 Online Store for Telescopes and Accessories | Published: 2026-10-31

Category: How-to Guides

Use the Celestron CrossAim 12.5mm reticle eyepiece to dial in finder alignment and center faint targets. Follow these steps for a repeatable, frustration-free process.

Quick answer

Use the Celestron CrossAim as your main eyepiece during alignment: center the target on the crosshairs, then adjust your finder so its pointer matches that same point. For centering faint objects, dim the red LED until the crosshairs are just visible.

Why a reticle eyepiece beats eyeballing the center

A standard eyepiece leaves you guessing whether a star is truly centered. The CrossAim's double crosshair gives you a fixed reference, so finder alignment and object centering become repeatable instead of approximate. The adjustable red LED brightness matters more than it seems: too bright and it washes out faint stars, too dim and you lose the crosshairs against a dark sky.

When the CrossAim is the right tool—and when it isn't

This 12.5mm eyepiece shines for polar alignment, off-axis guider centering, and any task that needs a precise reference point. It is not a replacement for a wide-field eyepiece when you are star-hopping or framing large objects; the crosshairs and narrow field can get in the way. Keep it as a dedicated alignment tool rather than your main observing eyepiece.

Step-by-step alignment and centering

Set up and insert the CrossAim: Place your telescope on a stable surface, insert the CrossAim into the focuser or diagonal, and tighten the thumbscrew gently. Turn on the red LED and set brightness to about halfway. Check that the eyepiece sits flush; a tilted eyepiece skews the crosshair center.
Center a bright star on the crosshairs: Use your finder to get a bright star into the field, then fine-tune with slow-motion controls until the star sits exactly where the crosshairs intersect. Dim the LED until the crosshairs are barely visible against the sky. If the star looks like a comet, you are out of focus—adjust focus before judging centering.
Align the finder to the crosshair center: Without moving the telescope, adjust the finder's alignment screws until its pointer (or crosshair) lands on the same star. Recheck by moving slightly off the star and re-centering with the finder. Make small adjustments and re-tighten lock screws evenly to avoid shifting the finder.
Center faint objects using the reticle: For deep-sky targets, keep the LED dim and use the crosshairs to place the object at the intersection. If the object is invisible, center on a nearby field star first, then switch to the target. A dim reticle preserves your dark adaptation better than a bright one.
Use with an off-axis guider: When guiding, insert the CrossAim into the guide port and center the guide star on the crosshairs. Lock the guide camera without moving the telescope. Verify the star stays centered after locking; any drift means the camera or eyepiece moved.

Product facts

Celestron CrossAim Reticle Eyepiece - 93235: 12.5mm focal length in a 1.25-inch barrel with a double crosshair reticle and adjustable red LED brightness. The 1.25-inch barrel fits most focusers and diagonals, while the dimmable reticle lets you match the crosshair brightness to the sky without losing faint stars.
Celestron CrossAim Reticle Eyepiece - 93235