Astro-Tech 24mm Illuminated Reticle Eyepiece

The economical Astro-Tech #AT24IL illuminated reticle 1.25" eyepiece helps you align your go-to telescope on the sky, check your polar alignment for astrophotography, center guide stars in an photoguide scope, and more . . . This Astro-Tech #AT24IL illuminated reticle 1.25" eyepiece is the perfect eyepiece for aligning go-to telescopes on the sky each night when you go out to observe. It is also ideal for checking your scope's polar alignment for long exposure astrophotography, for centering guide stars in an off-axis photoguide scope for astrophotography, or for testing the accuracy of your computer pointing or the periodic error of your tracking system. Priced as much as 40% less than competitive illuminated reticle eyepieces, the #AT24IL is yet another example of the Astro-Tech philosophy of "more performance for less money." Most conventional illuminated reticle eyepieces have a short focal length and limited eye relief, which can make for uncomfortable viewing, particularly if you wear eyeglasses. In comparison, the Astro-Tech #AT24IL has a long 24mm focal length for a wider field that makes it easier to locate guide stars. This virtually eliminates the need to swap out a high-power illuminated reticle with a lower power eyepiece to locate or center objects. Its very long 20mm eye relief and soft roll-down rubber eyecup make it very comfortable to use, whether you wear glasses to observe or not. You can use this Astro-Tech 1.25" eyepiece with any make or model of telescope or off-axis guidescope. The eyepiece reticle has a single etched crosshair precisely centered in eyepiece field of view for accurate results. A ribbed ring at the top of the eyepiece rotates to focus the crosshairs sharply to match your eyesight. The five-element optical system is fully multi-coated on all air-to-glass surfaces with high transmission anti-reflection coatings for bright, crisp views. The edges of the lenses are blackened for high contrast. The barrel is threaded for standard 1.25" filters. The metal-body cordless red LED (light emitting diode) crosshair illuminator has a rotary on/off switch with an integral brightness level control. Two supplied 1.5V watch/camera/calculator button batteries will power the illuminator for many hours of use. The supplied batteries are model GPA76, but you can also use the Duracell, Maxell, National, Panasonic, Sony, or Toshiba LR44; the Eveready or Philips A76; etc. When replacing batteries, be sure the battery - signs face the LED portion of the illuminator and the + signs face the on/off switch. Please note: While the manufacturer normally supplies batteries at no cost with this product as a convenience, the battery charge or useful life is not guaranteed. The batteries may arrive with their charge depleted or very low. In such a case, you will have to purchase replacement batteries locally, as battery life is not covered by the manufacturer's warranty. Tech Details:  Eye Relief 20mm Field of view 50 Focal Length 24mm Weight 4 oz. Warranty 1 year