Rear fan holder for Sky-Watcher Newton 200 mm

🎯 A rear fan holder designed primarily for dew prevention

This rear fan holder has been specifically designed for Sky-Watcher Newton telescopes with a 200 mm primary mirror, with a clear objective: to effectively prevent dew formation on the primary mirror, a common issue during humid nights, both in visual observing and astrophotography.

At this mirror size, internal thermal turbulence is generally a secondary concern. Here, the fan is primarily used to direct airflow onto the surface of the primary mirror, preventing condensation and allowing observing or imaging sessions to last significantly longer.

💧 Effectiveness and operating limits

The airflow is directed precisely toward the primary mirror, which allows:

• significantly delaying dew formation,
• and in most common conditions, preventing it altogether.

The system remains highly effective as long as the telescope is not pointed straight up toward the zenith for an extended period. In cases of very high humidity combined with prolonged zenith pointing, as with any passive ventilation solution, effectiveness may naturally be reduced.

🔧 Silent fan with vibration control

The fan used is a PC-grade fan, selected for its quiet operation and reliability. All potential vibration sources have been carefully addressed:

• rubber damping pads,
• fan mounting using flexible rubber pins similar to those found in high-end PC builds,
• effective mechanical decoupling between the fan and the holder structure.

Thanks to these design choices, vibrations are strongly damped, allowing the fan to be safely used:

• during visual observing,
• and also during astrophotography, without noticeable impact on image quality.

📷 Visual observing and astrophotography

The fan can remain in operation:

• during setup and cooldown,
• throughout visual observing sessions,
• and even during imaging sessions.

For even greater peace of mind, a version with an integrated speed controller is available. It allows fine adjustment of the fan speed, resulting in even quieter operation, especially appreciated for long-exposure imaging.

The fan can also be controlled via an ASIair or any compatible 12 V power management system.

⚡ Power supply

The fan operates on 12 V. The product is supplied with a 12 V cigarette-lighter power cable.
The 12 V power source itself is not included (external battery or power supply required).

📦 What’s included

• 1 rear fan holder for Sky-Watcher Newton 200 mm
• 3 retaining brackets
• 1 12 V cigarette-lighter power cable

Each holder is designed and assembled in our workshop, then visually inspected before shipping.