Celestron CrossAim 12.5mm Reticle Eyepiece - 1.25"
- 12.5mm Focal Length
- 40° Apparent Field of View
- Illuminated Double Crosshair Reticle
- Adjustable Red LED Brightness
- 1.25" Barrel Format
Simulate the exact field of view of the Celestron CrossAim 12.5mm Reticle Eyepiece - 1.25" with your specific telescope.
Launch Visual AssistantThe Celestron CrossAim 12.5mm Reticle Eyepiece places an illuminated double crosshair reticle within a 40° apparent field of view, built on a classic Plössl optical design. Its 12.5mm focal length generates the ideal magnification for manually guiding long exposures or precisely centering alignment stars. An adjustable red LED illuminator, powered by three included 1.5V batteries, keeps the reticle visible without compromising your dark adaptation.
The 12.5mm focal length strikes a critical balance for precision work. It delivers enough magnification to easily detect guide star drift during manual guiding, allowing you to make corrections before they trail the image. This focal length is also ideal for centering objects for GoTo alignment, ensuring your target is perfectly positioned on a small imaging sensor.
Unlike a single crosshair that can obscure a faint guide star, the double crosshair design creates a clean, open box in the center of the 40° field. This makes it simple to keep your target star perfectly framed without covering it. The adjustable red LED illumination allows you to set the brightness from a faint glow for dim targets to a more visible level for polar alignment, all while using fully-coated optics to maintain image contrast.
The double crosshair creates a small, open box in the center of the field. This allows you to frame a guide star without completely covering it, which is a common problem with single crosshairs, especially on fainter stars.
The Celestron CrossAim is designed for tasks requiring high-precision centering. Its primary uses are manual guiding for astrophotography, drift alignment for accurate polar alignment, and centering stars for GoTo system alignment.
The red LED illuminator is powered by three 1.5V alkaline batteries, which are included with the eyepiece. The brightness is adjustable via a dedicated on/off control knob, allowing you to match the reticle's visibility to the brightness of your target.
Yes, it functions as a standard 12.5mm Plössl eyepiece with a 40° field of view. However, the crosshair reticle will always be visible in the field, which can be distracting for purely observational viewing of planets or deep-sky objects where the reticle is not needed.
Point your telescope near the celestial equator and meridian, and place a star in the eyepiece. Rotate the CrossAim so one line is parallel to the star's east-west drift. You then adjust your mount's azimuth controls until the star no longer drifts north or south off that line. This precision is critical for preventing star trails during long exposures on targets like M42.
Yes, it's an excellent match. In a 1000mm telescope, the 12.5mm focal length yields 80x magnification (1000 / 12.5). This is a great power range for seeing subtle movements of a guide star, allowing for precise corrections without making the field of view too narrow or the image too dim.
| Focal Length | 12.5 mm |
| Apparent Field of View | 40° |
| Eyepiece Type | Plössl |
| Barrel Size | 1.25" |
| Coatings | Fully-Coated, Anti-Reflection Coatings |
| Reticle | Double Crosshair |
| Illuminator | Red LED with On/Off brightness control |
| Power Source | Three 1.5V alkaline batteries (included) |
Celestron CrossAim 12.5mm Reticle Eyepiece
× 1
1.5V Alkaline Batteries
× 3