Collection: Best Guide Scope for Redcat 51

Choosing the Best Guide Scope for RedCat 51 in Astrophotography

Astrophotography enthusiasts using the RedCat 51 alongside a DSLR camera often face the challenge of precise object targeting during their sessions. To address this issue, many turn to guide scopes and cameras to enhance their setup. In this guide, we'll explore the best guide scope options for the RedCat 51 and compatible cameras based on discussions from astrophotography forums.

Choosing the Right Guide Scope

1. William Optics 32mm Guide Scope (Weight: 0.24 Kg)

  • A lightweight and cost-effective option.
  • Suitable for the RedCat 51's small focal length.
  • Recommended by users for its efficiency.

2. William Optics 50mm Guide Scope (Weight: 0.46 Kg)

  • Slightly heavier but offers a larger aperture.
  • Considered a reliable choice for guiding.

3. Svbony SV165 Guide Scope

  • A budget-friendly alternative for those seeking affordability.
  • Users endorse its compatibility with the RedCat 51.

Expert Advice:

  • For the RedCat 51's small focal length, a smaller guide scope like the SV165 can be effective and more economical.

Guide Camera Options

1. ASI290MM Mini (Mono)

  • Recommended for guiding with the RedCat 51.
  • Offers monochrome imaging for better guiding accuracy.
  • Paired successfully with the SV165 by users.


  • An economical choice for guiding.
  • Compatibility with guide scopes like the SV165.

Expert Advice:

  • Monochrome cameras like the ASI290MM Mini are favored for guiding due to better performance.

User Experiences and Recommendations

1. Ease of Focus with Mini Guide System

  • Users report successful use with PHD2 for star tracking.
  • Patience required for focusing but effective once locked.

2. Compatibility Issues with RunCam

  • RunCam not recommended for guiding; designed for FPV drones.
  • Webcam use discouraged for guiding.

3. RedCat 51 and ZWO ASI Compatibility

  • Users integrate ZWO ASI cameras successfully with RedCat 51.
  • Seeking solutions for attaching accessories to the RedCat.

Considering Off-Axis Guiding

1. Guiding Equipment for Future Consideration

  • ZWO 30mm mini with ASI290MM recommended for RedCat 51.
  • Overkill for short focal lengths; suggested for longer focal lengths.

2. OAG (Off-Axis Guiding) Consideration

  • OAG can compensate for mirror movement.
  • Suggested for longer focal lengths; not necessary for short fracs like RedCat 51.

Expert Advice:

  • For RedCat 51 users, a separate guide scope is more intuitive, while OAGs are more compact.

Compatibility with ASIAIR Pro

1. ASIAIR Pro and ZWO Cameras Compatibility

  • ASIAIR Pro limited to ZWO cameras.
  • Recommendations include ASI120MM-S or ASI120MM-Mini for guiding.

2. Long-Term Consideration

  • Investing in a quality camera like ASI290MM for future-proofing.
  • OAG with the 290MM suggested for versatility.

Frequently Asked Questions About Guide Scopes for RedCat 51

1. What is the significance of the guide scope in astrophotography?

The guide scope plays a crucial role in astrophotography by providing a stable and accurate reference for tracking celestial objects. It works in tandem with a guide camera to make real-time adjustments to the mount, ensuring precise and smooth tracking of the target.

2. Why choose a smaller guide scope for the RedCat 51?

Given the RedCat 51's small focal length, a smaller guide scope, such as the SV165, is often recommended. It not only complements the lightweight nature of the RedCat setup but also proves to be more cost-effective while delivering satisfactory guiding performance.

3. Is the ASI290MM Mini the best choice for guiding with the RedCat 51?

The ASI290MM Mini is a popular choice among users for guiding with the RedCat 51. Its monochrome imaging capabilities, coupled with its compatibility with smaller guide scopes, make it a reliable option for achieving accurate guiding.

4. What are the considerations for off-axis guiding (OAG)?

While OAG can compensate for mirror movement and is often preferred for longer focal lengths, it may be considered overkill for smaller fracs like the RedCat 51. Users generally find separate guide scopes more intuitive for setups like the RedCat, providing effective guiding without the complexities of OAG.

5. Can the ASIAIR Pro work with any guide scope or camera?

The ASIAIR Pro is designed to work seamlessly with ZWO cameras, and specific recommendations include the ASI120MM-S or ASI120MM-Mini for guiding purposes. It's crucial to ensure compatibility between the ASIAIR Pro and the chosen camera for a smooth integration into the astrophotography setup.

6. What factors should be considered for long-term guiding equipment choices?

Investing in quality guiding equipment that aligns with your long-term astrophotography goals is essential. While a smaller setup like the ASI120MM Mini may suffice for the RedCat 51, users looking for future-proofing often opt for the ASI290MM for its superior performance. Additionally, an OAG with the 290MM is suggested for versatility as your equipment base grows.

7. How can I attach accessories to the RedCat 51?

The RedCat 51 features 1/4-20 holes for accessory attachment. Understanding the threading specifications, such as the 1/4" 20 TPI, allows users to find suitable clamps or alternative rings for secure mounting of guide scopes, cameras, or other accessories.

8. Is webcam use recommended for guiding?

Webcams, particularly those designed for planetary work, may not be the best choice for guiding. Astrophotographers generally favor dedicated guide cameras like the ASI290MM Mini due to their monochrome imaging capabilities and suitability for the guiding task.

Expert Tips and Best Practices for RedCat 51 Guiding

1. Focus and Patience with Mini Guide Systems

  • Achieving optimal focus with mini guide systems might require patience and persistence.
  • Utilize tools like PHD2 for star tracking and SharpCap for assisting with focus.

2. Avoid Color Cameras for Guiding

  • Color cameras, like the RunCam Night Eagle Astro, are not suitable for guiding.
  • Monochrome cameras, such as the ASI290MM Mini, are recommended for their superior performance in guiding applications.

3. Consider Future Expansions

  • When planning your guiding setup, consider potential future expansions in your astrophotography equipment.
  • Investing in quality, versatile equipment early on can save you from frequent upgrades as your skills and gear evolve.

4. Separate Guide Scopes vs. Off-Axis Guiding (OAG)

  • For RedCat 51 and similar setups, separate guide scopes are often more intuitive.
  • OAGs, while effective, may bring additional challenges, and their compactness is more beneficial at longer focal lengths.

5. Thread Standards and Mounting Considerations

  • Understanding threading standards, such as 1/4" 20 TPI, is crucial for finding compatible clamps and rings for mounting accessories.
  • Ensure secure mounting to prevent flexure between the guide scope and the main optical tube.

6. Compatibility of ASIAIR Pro with ZWO Ecosystem

  • ASIAIR Pro is limited to ZWO cameras, emphasizing the importance of choosing cameras within the ZWO ecosystem.
  • Research and read community reviews for insights into the compatibility and performance of specific camera models.

7. Balancing Budget and Longevity

  • Striking a balance between budget constraints and long-term goals is key.
  • Consider the fundamental rule in astrophotography: invest in the best equipment you can afford to future-proof your setup.

8. Guiding Focal Length vs. Imaging Focal Length

  • While guiding focal length is essential, it's not the sole determinant of successful guiding.
  • Both separate guide scopes and OAGs can effectively guide at shorter focal lengths, with each approach having its own set of advantages.

9. User Experience with Sharpstar 65Q and Meade ACF C8

  • Users share personal experiences with guiding setups using the Sharpstar 65Q and Meade ACF C8 telescopes, emphasizing the use of the ASI120MM for successful guiding.

10. Guiding is a Growing Process

  • Astrophotography is a continuously evolving hobby.
  • Plan for future growth, and remember that guiding is about more than just equipmentβ€”it's a holistic approach to capturing the wonders of the night sky.

Incorporating these expert tips and best practices into your RedCat 51 guiding setup can enhance your overall astrophotography experience. As you embark on this captivating journey, remember that the key to success lies in a thoughtful and well-informed approach to selecting and utilizing your guiding equipment.


In conclusion, the ideal guide scope for the RedCat 51 depends on individual preferences, budget constraints, and long-term plans for astrophotography equipment. The consensus leans toward a smaller guide scope like the SV165 paired with a reliable monochrome camera such as the ASI290MM Mini for optimal guiding performance. Always consider your specific needs and the advice of experienced astrophotographers when making your decision.