Bresser EXPLORE SCIENTIFIC 8x50 Finder and Guider Scope with Helical Focuser

Universal 8x50 Viewfinder and Guide Telescope

The Bresser EXPLORE SCIENTIFIC 8x50 Finder and Guider Scope features a 50mm objective lens with a focal length of 220mm, providing excellent image sharpness and a bright, crisp view. It includes a removable eyepiece unit with crosshairs that have adjustable red LED illumination, powered by two LR41 coin batteries. The crosshairs feature scale markings with 1-degree graduations and an open center for precise object centering.

Optical and Mechanical Features

• Multi-coated lens surfaces (FMC) ensure high light transmission and weather resistance.
• Very large field of view (FOV) of 6.96 degrees facilitates easy object location and adjustment.
• Independent focusing of the main lens and crosshairs for optimal eye comfort.
• Precise helical focuser with a 28mm travel range and laser-engraved millimeter scale (0 to 28mm) for sensitive focusing.
• Close focus distance of 3 meters.

Autoguiding Capabilities

This scope is designed for autoguiding in astrophotography, allowing correction of mechanical tracking errors during long exposure imaging. It can be mounted parallel to the main telescope using the existing or included viewfinder shoe. The rear end features a 1.25 inch (31.7mm) plug-in connection and a T2 camera thread (M42x0.75mm) for attaching a tracking camera securely with a brass ring clamp and three clamping screws. The focal plane (backfocus) is approximately 22mm behind the T2 thread.

Additional Uses and Compatibility

Besides autoguiding, the scope can serve as a compact travel telescope. With optional eyepieces ranging from 5 to 26mm focal length and 1.25 inch plug connection, magnifications from 8x to 40x are achievable. Recommended eyepieces include the EXPLORE SCIENTIFIC 52° and 62° LER series. Note that only straight viewing is possible.

Mount and Construction

• Robust aluminum viewfinder holder and mount compatible with many telescopes such as EXPLORE SCIENTIFIC and BRESSER MESSIER.
• Included viewfinder shoe with bore distances of 31.7mm longitudinally and transversely, attachable via four M5 screws.
• Six large knurled adjustment screws with plastic tips prevent scratching and allow easy alignment, even with damp fingers.

Technical Specifications

• Magnification: 8x
• Objective diameter: 50mm
• Focal length: 220mm
• Field of view: 6.96°
• Focuser travel: 28mm
• Close focus distance: 3 m
• Camera connection: 1.25 inch plug-in or T2 thread (M42x0.75mm)
• Backfocus: approx. 22mm behind T2 thread
• Crosshair illumination: adjustable red LED powered by 2x LR41 batteries
• Maximum camera weight: 550g

Scope of Delivery

• 8x50 viewfinder/guiding telescope
• Eyepiece unit with crosshair
• Crosshair illumination unit with batteries
• Viewfinder holder with viewfinder shoe
• Instruction manual