Celestron 9.25-inch Dew Heater Ring (Part #94052)
Permanent, efficient dew control—right at the glass—for your 9.25" SCT or EdgeHD
The 9.25" Schmidt-Cassegrain is something of a cult classic—big enough to dive deep, compact enough to travel, and optically sharper than many scopes twice its price. But its generous corrector plate is still vulnerable to one timeless enemy: dew.
The Celestron Dew Heater Ring offers a smarter, more efficient solution by warming the corrector glass directly, not the metal cell around it. It replaces your stock retaining ring and becomes a permanent, precision-machined part of your telescope—so you'll never forget to pack it, and you'll never deal with slipping heater straps again.
How it works
Where traditional dew straps waste energy warming the front housing, the Dew Heater Ring puts the heat exactly where it’s needed—on the corrector itself. An internal resistive heating element runs evenly around the lens perimeter, and a built-in thermistor sensor communicates with Celestron's Smart DewHeater Controllers (sold separately) to maintain just the right temperature in any conditions.
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Efficient, direct-contact heating preserves battery life and improves results
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Rigid aluminum construction supports both the corrector and internal circuitry
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Velvet-lined interior protects coatings while distributing clamping pressure
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Storage clips keep power and thermistor jacks secured when not in use
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Cable management clip mounts to the front cell for strain relief and cleaner routing
This is a permanent installation—you install it once, and your dew control becomes part of the telescope itself.
Easy, one-time installation
For Celestron 9.25" OTAs made in 2006 or later, installation is a direct swap. Use the included paper installation shield to protect your corrector during the process. Remove the stock retaining ring, place the Dew Heater Ring in its place, and re-secure with the existing screws. The ring is designed to accommodate your telescope’s standard dust cover and will not affect collimation.
Technical Specs
| Feature |
Description |
| Compatibility |
9.25" Celestron SCT and EdgeHD (2006 and newer) |
| Power Input |
12V DC (5.5mm × 2.1mm barrel connector, tip positive) |
| Power Draw |
Approximately 20–25 watts (controller-regulated) |
| Thermistor Jack |
2.5mm audio plug, compatible with Celestron Smart DewHeater Controllers |
| Construction |
Precision aluminum with velvet-lined interior |
| Included Accessories |
Power jack extension cable, cable management clip, paper installation shield |
| Installation |
Replaces existing corrector retaining ring (non-invasive, reversible) |
Note: While compatible with third-party 12V controllers for heater function, the ring’s built-in thermistor sensor only works with Celestron’s Smart Controllers.
Observing Tip
For even greater efficiency, pair this ring with a dew shield. Passive shielding reduces radiant cooling, which means your ring uses less power—and your battery lasts longer. A Smart Controller will throttle the output dynamically, conserving energy while still keeping your optics dew-free.
Final Thoughts
If you’ve made the smart choice with a 9.25" SCT or EdgeHD, this is the dew solution to match. The Celestron Dew Heater Ring is efficient, permanent, and purpose-built—not a workaround. It becomes part of your OTA, ready for action every night, no matter the forecast.
Newer generation Celestron SCTs built in the year 2006 or later are compatible with the Dew Heater Ring. These newer OTAs have a trilobed shape on the rear cell. In addition, newer generation 14" SCTs have a rounded rear cell. See photo examples below. All EdgeHD, RASA, 6” Schmidt-Cassegrain and 9.25” Schmidt-Cassegrain telescopes are compatible with the Dew Heater Ring.
Enhance your setup
To achieve the highest level of dew prevention while maximizing power efficiency, we strongly recommend pairing the Dew Heater Ring with a Smart DewHeater Controller (sold separately). The controller uses the ring's built-in thermistor and its internal environmental sensor to provide just the right amount of heat to the corrector to prevent dew based upon the ambient temperature, ambient humidity, and temperature of the Schmidt corrector, which can dramatically reduce the ring’s power draw, greatly increasing battery life. The ring also includes an extension cable for connecting the ring directly to one of the controllers’ heater output ports, or to a third-party controller’s heater output port. (Note: the ring’s integrated thermistor is only compatible with the Celestron Smart DewHeater Controllers).
We also recommend adding a dew shield to your setup. While not mandatory, a shield will cut down on the amount of power the Dew Heater Ring needs to keep the optics clear.
