Pegasus Astro Temperature Sensor for FocusCube 1 and 2 (RJ45)

Product Overview

This is the Pegasus Astro digital temperature probe for the FocusCube 1 and FocusCube 2, terminating in an RJ45 plug for the controller's sensor port. It is the part that makes temperature-compensated focusing possible: the controller reads the probe, notices the night cooling, and moves the focuser to match.

It is also the replacement part if the original probe has been damaged or lost.

Who It's For

This is a good match if you:

• Run a FocusCube 1 or 2 and want the controller to track focus drift as the temperature falls through the night.
• Image long sessions where focus at 10 pm and focus at 3 am are not the same number.
• Have lost or damaged the original probe and need the matching replacement.
• Operate remotely and want focus to follow temperature without anyone intervening.

Key Features & Design

• Digital temperature probe: a digital sensor rather than an analogue thermistor, so the reading arrives at the controller already converted.
• RJ45 termination: matches the sensor port on the FocusCube 1 and 2.
• Enables temperature compensation: the controller's software and ASCOM driver use the reading to offset focus position automatically.
• Mounts at the focuser: the probe reads the temperature where focus actually shifts, rather than ambient air some distance away.

Recommended Uses

• Temperature-compensated focusing across a long imaging session.
• Logging focuser temperature alongside your imaging data.
• Replacing a damaged or missing FocusCube probe.
• Unattended remote operation where nobody is present to refocus.

Compatibility and Accessory Notes

• FocusCube 1 and FocusCube 2, using the RJ45 sensor connector.
• Not the probe for the DMFC, Prodigy or FocusCube 3 — those use the 3.5 mm jack version, which we stock as a separate part.
• Not the environmental sensor for the powerboxes — the Ultimate Powerbox and Pocket Powerbox range use the RJ12 environmental sensor, also a separate part we carry.
• Unsure which probe your controller takes? Look at the socket, or send us a photo and we will identify it with you before you order.

Good to Know Before You Order

• Connector type is the thing to get right. Pegasus uses RJ45, 3.5 mm jack and RJ12 sensors across the range, and they are not interchangeable. This one is RJ45, for the FocusCube 1 and 2.
• Temperature compensation needs a coefficient. The probe supplies the temperature; how far the focuser moves per degree is something you establish for your own telescope, and the controller software walks you through it.
• Pegasus Astro publishes no probe length or accuracy figure for this SKU on its own. Those rows are left out rather than carried across from another product's sensor.
• Pegasus Astro publishes no weight for this part. Our declared shipping weight of 1 lb is a carrier minimum, not the probe's true mass — worth knowing if you are ordering several small items together.

Frequently Asked Questions

Is it difficult to set up?

No. It plugs into the sensor port and the controller software picks it up. The only setup step worth doing is establishing the temperature-compensation coefficient for your telescope, which is a one-off.

Will it fit my FocusCube 3?

No — the FocusCube 3 uses the 3.5 mm jack probe, which we stock separately.

Do I need it, or does the FocusCube work without one?

The focuser works without it. The probe is what adds temperature compensation and temperature logging.

Where should the probe sit?

At the focuser, so it reads the temperature of the part that is actually moving, rather than air some distance from the telescope.

Is this the same as the powerbox environmental sensor?

No. The powerboxes use an RJ12 environmental sensor that also reads humidity and dew point. This one is the focuser temperature probe.

Bottom Line

In short: the RJ45 digital temperature probe that gives a FocusCube 1 or 2 temperature-compensated focusing — and the right replacement if the original has gone missing.