Fog and condensation are common challenges for astronomers observing in cold or humid conditions. The Vaonis Vespera Hygrometer Sensor is an intelligent accessory designed to prevent lens fogging and preserve image quality throughout your observing session.

The hygrometer continuously measures ambient temperature and humidity. When predefined thresholds are reached, it automatically activates Vespera’s integrated anti-fog system.

Heat generated around the lens gently removes condensation, ensuring clearer observations and sharper astrophotography results without user intervention.

• Activates the built-in anti-fog (demisting) system
• Improves both visual observation and image sharpness
• Ideal for humid or cold climates (including coastal and winter conditions)

How the Anti-Fog System Works

Condensation affects focus accuracy and image sharpness by introducing halos and reducing star definition. When equipped with the hygrometer sensor, Vespera automatically enables its demisting system whenever fogging conditions are detected.

This improves image acquisition efficiency and ensures that only high-quality frames are retained during image processing.

Discreet, Precision Design

Measuring less than 13 mm, the hygrometer features one of the smallest electronic boards ever designed by Vaonis engineers. It integrates discreetly into Vespera’s optical arm and remains fully compatible with the use of optical filters.

Once installed, the sensor automatically manages anti-fog activation and deactivation, requiring no manual adjustments.

Installation & Instructions for Use

The box includes:

• The hygrometer sensor with mounting screw
• A mini screwdriver

Remove the standard Vespera lens ring and insert the hygrometer into the dedicated notch above the lens. Secure it firmly using the supplied screwdriver. The sensor must not move once installed.

To confirm correct installation, connect Vespera to your mobile device and open the Singularity app. Ambient temperature and humidity readings will appear in the Space Centre under the Instrument screen.

Usage Recommendations

• Ensure Vespera is powered off before installing or removing the sensor
• Leave the hygrometer installed to prevent loss or damage
• Anti-fog activation increases battery consumption; fully charge your station before use

In cold weather, allow your Vespera to acclimatise outdoors for at least 30 minutes before observation to minimise condensation caused by temperature differences.