ZWO 30mm f/5 APO Guide Scope

Triplet APO Optics at 150mm Focal Length

Unlike standard achromatic guide scopes, this scope's triplet lens design corrects for chromatic aberration, rendering guide stars as tight, focused points of light without color fringing. This optical correction allows autoguiding software to calculate a more accurate centroid, which translates directly to tighter, rounder stars in your final image. The 150mm focal length provides enough image scale to effectively guide primary imaging telescopes up to 750mm in focal length.

Precise Helical Focuser at Just 0.77 lb.

Achieving and maintaining sharp focus on your guide star is non-negotiable for accurate guiding. This scope features a non-rotating helical focuser with a locking screw, allowing you to make fine adjustments and then secure the focus position against accidental bumps or temperature shifts. The entire optical tube assembly weighs only 0.77 lb., adding minimal load to your mount and making it easy to balance your entire imaging rig.

• Direct Threaded Connection: The rear of the focuser includes M42x0.75 T-threads, allowing you to securely attach any ZWO ASI camera for a rigid, flex-free connection.
• 1.25" Compatibility: For cameras with a 1.25" nosepiece, a standard compression ring holder provides a secure grip without marring the barrel.
• Synta-Style Mounting: The included dovetail bar fits standard finder shoes on most telescopes, making it a simple drop-in replacement or addition to your setup.

ZWO 30mm f/5 APO vs. the Original 30mm f/4

While the original ZWO 30mm f/4 guide scope is a capable and compact option, the f/5 APO model is a significant optical upgrade. The primary differences lie in the optical design and focal length, which directly impact guiding accuracy with longer telescopes.

• Optical Design: The older f/4 model uses an achromatic doublet design, which can exhibit minor color fringing on bright stars. The f/5 APO uses a triplet lens system to virtually eliminate this, producing sharper stars for more precise centroid calculations.
• Focal Length: The f/5 APO's longer 150mm focal length provides a more detailed view of guide stars compared to the 120mm of the f/4 model. This increased image scale allows for more accurate guiding corrections, especially when paired with longer focal length imaging scopes.