Refractor guide scope Skywatcher Evoguide 50 — 50 mm aperture, 240 mm focal length

The Skywatcher Evoguide 50 is a compact refractor guide scope with a 50 mm aperture and a 240 mm focal length, designed for autoguiding and wide-field imaging. It is intended to work with guide cameras to provide accurate tracking corrections to an equatorial or alt-azimuth mount when used with a guiding system. The Evoguide 50 is lightweight and portable, making it suitable for field astrophotography and for mounting alongside a main telescope as part of an imaging rig.

Advantages

The Evoguide 50 combines a short focal length and modest aperture to create a wide guide field that simplifies framing and star selection for guiding cameras. Its compact optical tube and low weight reduce the load on telescope mounts and make setup and alignment quicker. The refractor design minimizes alignment complexity and provides a stable, collimated guide image useful for correcting tracking errors during long exposures.

Suitable for

• Autoguiding with dedicated guide cameras
• Wide-field astrophotography and landscape sky imaging
• Portable or field setups where low weight is important
• Mount alignment and testing in amateur observatories

Key specifications

• Aperture: 50 mm
• Focal length: 240 mm
• Optical type: refractor guide scope
• Design purpose: autoguiding and wide-field imaging
• Physical attributes: compact and lightweight tube suitable for mounting alongside a main telescope

How to use

Mount the Evoguide 50 on the guide or parallel riser bracket of your telescope mount so that its optical axis is as parallel as possible to the main instrument. Attach a compatible guide camera to the focuser, balance the mount, and perform initial polar alignment or drift alignment according to your mount type. Use a guiding software package to select a guide star within the Evoguide 50’s field, calibrate the guiding routine, and monitor corrections while capturing long-exposure images with your main camera.

Usage recommendations

For reliable autoguiding, pair the Evoguide 50 with a sensitive guide camera that has small pixels and good low-light performance. Ensure firm, stable mounting and re-check collimation and focus before long imaging runs. Because of the short focal length, the Evoguide 50 is forgiving for initial alignment but may require careful calibration in systems with significant periodic error or flexure.