SVBONY SV545 45mm f/4.5 203mm Petzval Refractor Astrograph Lens

5-Element Petzval Design: A Natively Flat 45mm Astrograph

The SV545's optical core is a 5-element Petzval design arranged in 3 groups, specifically engineered to eliminate field curvature right out of the box. This advanced optical system means you don't need a separate field flattener to achieve pinpoint stars, simplifying your imaging train and reducing setup complexity. The design controls edge distortion and chromatic aberration, delivering clear, high-quality celestial images.

• Fully Multi-Coated (FMC) Optics: All air-to-glass surfaces are coated to maximize light transmission and contrast, ensuring rich color and detail in your images.
• Integrated Corrector: The Petzval layout functions as a complete system with a built-in flat field, saving the setup time of external correctors.
• APO Performance: Edge distortion and chromatic aberration are greatly controlled, for clear, high-quality celestial images.

203mm Focal Length at f/4.5: Wide-Field Nebulae and Star Fields

With a 45mm aperture and a fast f/4.5 focal ratio, you can capture faint, extended objects with shorter exposure times than slower optical systems. The 203mm focal length is purpose-built for capturing large swaths of the Milky Way, sprawling emission nebulae like the North American Nebula (NGC 7000), and the full expanse of galaxies like the Andromeda Galaxy (M31). This combination suits expansive mosaics or framing large targets in a single shot.

While optimized for astrophotography, SVBONY designed the SV545 to meet the needs of terrestrial imaging too, such as landscapes and wildlife. Its primary limitation is its 45mm aperture, making it a specialist for wide-field views rather than high-magnification planetary imaging.

EAF-Ready Helical Focuser with 360° Camera Rotator

Focus is set with the one-piece helical focuser. The integrated design includes a pre-equipped mounting bracket for an Electronic Auto Focuser (EAF), allowing you to automate your focusing routine for maximum sharpness throughout an imaging session. This gives smooth, automated fine-tuning during imaging (the EAF motor itself is sold separately).

• Lockable 360° Rotator: A camera angle adjuster is integrated into the body, letting you rotate the camera to frame your target without unscrewing it from the lens. Once set, the CAA lock screw secures the orientation.
• Manual Precision: For manual focusing, you turn the threaded focusing ring. By using your camera's live view magnification, you can slowly and precisely dial in focus on stars.

55mm Back Focus, M48 Connection, and 2" Filter Holder

The SV545 simplifies camera and accessory integration. The rear of the astrograph terminates in an M48x0.75 male thread that takes camera adapter rings for various camera brands. The back focus is 55mm from the rear thread surface (excluding the thread length); allow for your camera's flange distance and the depth of each adapter. For astronomy cameras, filter wheels or filter drawers, ask the maker of those accessories for connection guidance.

• Integrated 2" Filter Holder: The lens comes with a pre-assembled 2-inch filter holder, allowing you to easily install light pollution, narrowband, or color filters directly into the optical train.

2750g All-Metal Construction with Dual Dovetail Plate

Constructed with an all-metal body and sealed optics, the SV545 is built for durability during fieldwork in changing environmental conditions. Its estimated weight is 2750g, and the lens is compact and lightweight. The mounting system is designed for broad compatibility with most equatorial mounts and camera tripods.

• Dual Dovetail Plate: The included plate supports both Arca-Swiss and Vixen-style mounting systems, allowing for quick and secure attachment without needing additional hardware.
• Integrated Handle: The top handle provides a secure grip for transport and setup, and also features an integrated Vixen-style finder saddle for attaching a guide scope or other aiming devices.

Unboxing the SV545: From Padded Case to First Light

The SVBONY SV545 arrives ready for the field in a soft padded case for safe storage and transport. The package includes all the necessary components to get started. The main lens assembly comes with a plastic lens cover, an M48 metal lens cover, an EAF mount kit, a wrench and screw, the dual dovetail plate, and the combination handle/finder saddle. A 2" filter holder is pre-installed within the lens body for immediate use.

Getting started involves attaching the dovetail plate to your mount, connecting your M48-threaded camera to the rear of the lens while observing the 55mm back focus distance, and then using the helical focuser to achieve a sharp image. The included camera angle adjuster allows you to rotate your camera for optimal composition before locking it down for your imaging run.