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Dew Prevention and Control

Dew ends more Canadian observing sessions than cloud does. A corrector plate or objective radiating heat to a clear sky drops below the dew point well before the air does, and once condensation forms on a large optic it will not clear on its own. David Astro carries dew prevention and control products in Canada — heater straps, controllers, shields and power distribution — held in stock for fast domestic shipping.

Prevention is straightforward and cheap; recovery is neither. Tell us your telescope aperture and where you observe and we will specify a system that keeps optics clear all night.

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CA$361.00 - CA$361.00
CA$361.00
CA$361.00 - CA$361.00
CA$361.00

Celestron Aluminum Dew Shield with Cover Cap - 11"

CEL-94023
1 in stock

Protects 11" Schmidt-Cassegrain, EdgeHD, and RASA corrector plates from dew Rigid aluminum construction weighs 3.4 lbs and will not flex or de...

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CA$361.00 - CA$361.00
CA$361.00
CA$361.00 - CA$361.00
CA$361.00
CA$431.00 - CA$431.00
CA$431.00
CA$431.00 - CA$431.00
CA$431.00

Celestron Aluminum Dew Shield with Cover Cap - 14"

CEL-94024

Protects 14" EdgeHD, RASA, and SCT corrector lenses from dew Rigid aluminum construction weighs 5.4 lbs and will not flex or sag Velvet-lined inte...

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CA$431.00 - CA$431.00
CA$431.00
CA$431.00 - CA$431.00
CA$431.00
CA$160.00 - CA$160.00
CA$160.00
CA$160.00 - CA$160.00
CA$160.00

Celestron Aluminum Dew Shield with Cover Cap - 6"

CEL-94020
2 in stock

Custom-fit for all 6” Celestron Schmidt-Cassegrain telescopes Rigid aluminum construction prevents flexing and improves stability Velvet-lined int...

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CA$160.00 - CA$160.00
CA$160.00
CA$160.00 - CA$160.00
CA$160.00
CA$250.00 - CA$250.00
CA$250.00
CA$250.00 - CA$250.00
CA$250.00

Celestron Aluminum Dew Shield with Cover Cap - 8"

CEL-94021
1 in stock

Rigid aluminum construction prevents flexing and deformation Extends 12.4" from the front of the telescope to block dew and stray light Velvet-lin...

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CA$250.00 - CA$250.00
CA$250.00
CA$250.00 - CA$250.00
CA$250.00
CA$292.00 - CA$292.00
CA$292.00
CA$292.00 - CA$292.00
CA$292.00

Celestron Aluminum Dew Shield with Cover Cap - 9.25"

CEL-94022
2 in stock

Extends 14.4" to prevent dew formation on 9.25" SCT & EdgeHD corrector plates Blocks stray light to improve image contrast for visual and imag...

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CA$292.00 - CA$292.00
CA$292.00
CA$292.00 - CA$292.00
CA$292.00
CA$146.00 - CA$146.00
CA$146.00
CA$146.00 - CA$146.00
CA$146.00

Celestron Dew Heater Ring - 11"

CEL-94053
2 in stock

Designed for 11" Celestron SCT, EdgeHD, and RASA telescopes Delivers up to 30 watts of direct heating to the corrector plate Connects via a standa...

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CA$146.00 - CA$146.00
CA$146.00
CA$146.00 - CA$146.00
CA$146.00
CA$229.00 - CA$229.00
CA$229.00
CA$229.00 - CA$229.00
CA$229.00

Celestron Dew Heater Ring - 14"

CEL-94054

Maintains clear optics by directly heating your 14" corrector plate Delivers up to 52 watts of heating power for use in heavy dew conditions Rigid...

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CA$229.00 - CA$229.00
CA$229.00
CA$229.00 - CA$229.00
CA$229.00
CA$60.00 - CA$60.00
CA$60.00
CA$60.00 - CA$60.00
CA$60.00

Celestron Dew Heater Ring - 5"

CEL-94055
1 in stock

Permanently mounts to 5" Schmidt-Cassegrain telescopes Directly heats the corrector lens for maximum efficiency Draws a maximum of 7 watts at 12V ...

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CA$60.00 - CA$60.00
CA$60.00
CA$60.00 - CA$60.00
CA$60.00
CA$64.00 - CA$64.00
CA$64.00
CA$64.00 - CA$64.00
CA$64.00

Celestron Dew Heater Ring - 6"

CEL-94050
4 in stock

Maintains clear optics on your 6" Schmidt-Cassegrain Delivers up to 12 watts of direct heating power Durable aluminum ring with a 153.4mm inner di...

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CA$64.00 - CA$64.00
CA$64.00
CA$64.00 - CA$64.00
CA$64.00
CA$78.00 - CA$78.00
CA$78.00
CA$78.00 - CA$78.00
CA$78.00

Celestron Dew Heater Ring - 8"

CEL-94051
2 in stock

Permanently mounts to 8" SCT, EdgeHD, and RASA telescopes Directly heats corrector glass for maximum efficiency 20 watts of heating power prevents...

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CA$78.00 - CA$78.00
CA$78.00
CA$78.00 - CA$78.00
CA$78.00
CA$114.00 - CA$114.00
CA$114.00
CA$114.00 - CA$114.00
CA$114.00

Celestron Dew Heater Ring - 9.25"

CEL-94052
4 in stock

Designed for Celestron 9.25" Schmidt-Cassegrain and EdgeHD telescopes Delivers up to 24 watts of heating power directly to the corrector lens Ligh...

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CA$114.00 - CA$114.00
CA$114.00
CA$114.00 - CA$114.00
CA$114.00
CA$50.00 - CA$50.00
CA$50.00
CA$50.00 - CA$50.00
CA$50.00

Celestron Dew Shield DX for C6 & C8

CEL-94018
12 in stock

Prevents dew formation on 6" and 8" Schmidt-Cassegrain, EdgeHD, and RASA corrector plates Blocks stray light to improve image contrast Constructed...

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CA$50.00 - CA$50.00
CA$50.00
CA$50.00 - CA$50.00
CA$50.00
CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00

Celestron Dew Shield DX for C9.25 & C11

CEL-94016
9 in stock

Prevents dew formation on 9.25" and 11" Schmidt-Cassegrain, EdgeHD, and RASA corrector plates Blocks stray light to increase image contrast Flexib...

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CA$83.00 - CA$83.00
CA$83.00
CA$83.00 - CA$83.00
CA$83.00
CA$375.00 - CA$375.00
CA$375.00
CA$375.00 - CA$375.00
CA$375.00

Celestron Smart Dew Heater Controller 2x

CEL-94035
1 in stock

Controls 2 independent dew heater channels Provides 7A max 12V DC power output for mounts or accessories Integrated environmental sensor for real-...

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CA$375.00 - CA$375.00
CA$375.00
CA$375.00 - CA$375.00
CA$375.00
CA$625.00 - CA$625.00
CA$625.00
CA$625.00 - CA$625.00
CA$625.00

Celestron Smart Dew Heater Controller 4x

CEL-94036

Controls up to 4 dew heater channels with intelligent power optimization Provides centralized power with 3x 12V DC, 1x 3V-12V variable DC, and 3x ...

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CA$625.00 - CA$625.00
CA$625.00
CA$625.00 - CA$625.00
CA$625.00
CA$22.00 - CA$22.00
CA$22.00
CA$22.00 - CA$22.00
CA$22.00

Celestron Thermistor for Smart DewHeater Controllers

CEL-94037

Enables smart temperature control for third-party dew heater bands Connects to Celestron Smart DewHeater Controllers (sold separately) Standard 2....

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CA$22.00 - CA$22.00
CA$22.00
CA$22.00 - CA$22.00
CA$22.00
CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00

Dew-Not Heater Strip - .965" Eyepiece

DN001
1 in stock

The Dew-Not Dew Heaters are an essential accessory for every astronomy enthusiast aiming to enhance their stargazing experience. These dew heaters...

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CA$39.00 - CA$39.00
CA$39.00
CA$39.00 - CA$39.00
CA$39.00
CA$87.00 - CA$87.00
CA$87.00
CA$87.00 - CA$87.00
CA$87.00

Dew-Not Heater Strip - 10" Scope

DN011

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$87.00 - CA$87.00
CA$87.00
CA$87.00 - CA$87.00
CA$87.00
CA$91.00 - CA$91.00
CA$91.00
CA$91.00 - CA$91.00
CA$91.00

Dew-Not Heater Strip - 11" Scope

DN012
2 in stock

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$91.00 - CA$91.00
CA$91.00
CA$91.00 - CA$91.00
CA$91.00
CA$95.00 - CA$95.00
CA$95.00
CA$95.00 - CA$95.00
CA$95.00

Dew-Not Heater Strip - 12" Scope

DN013
1 in stock

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$95.00 - CA$95.00
CA$95.00
CA$95.00 - CA$95.00
CA$95.00
CA$98.00 - CA$98.00
CA$98.00
CA$98.00 - CA$98.00
CA$98.00

Dew-Not Heater Strip - 14" Scope

DN014
2 in stock

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$98.00 - CA$98.00
CA$98.00
CA$98.00 - CA$98.00
CA$98.00
CA$108.00 - CA$108.00
CA$108.00
CA$108.00 - CA$108.00
CA$108.00

Dew-Not Heater Strip - 16" Scope

DN015

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$108.00 - CA$108.00
CA$108.00
CA$108.00 - CA$108.00
CA$108.00
CA$48.00 - CA$48.00
CA$48.00
CA$48.00 - CA$48.00
CA$48.00

Dew-Not Heater Strip - 3" Scope

DN004

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$48.00 - CA$48.00
CA$48.00
CA$48.00 - CA$48.00
CA$48.00
CA$42.00 - CA$42.00
CA$42.00
CA$42.00 - CA$42.00
CA$42.00

Dew-Not Heater Strip - 32mm Guide Scope or 1.25" Eyepiece

DN002
4 in stock

Dew-Not™ has been involved in the design and manufacture of resistive heating elements for over 30 years. Their dew heater strips uses a thick film...

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CA$42.00 - CA$42.00
CA$42.00
CA$42.00 - CA$42.00
CA$42.00

How Dew Forms and How to Stop It

An optic pointed at a clear sky radiates heat into space and cools below ambient air temperature. When it falls below the dew point, water condenses on it. The fix is to hold the glass a few degrees above ambient, not to heat it aggressively.

  • Heater straps: Resistive bands sized to specific apertures, wrapped near the objective or corrector to keep the glass just above dew point.
  • Dew controllers: Pulse-width controllers that regulate power rather than running heaters continuously, which saves battery and avoids introducing tube currents.
  • Dew shields: Extend the tube beyond the objective, reducing the sky area the optic radiates to. Passive, free to run, and often enough on their own for refractors.
  • Heated eyepiece and finder bands: Small straps for eyepieces, finders and guide scopes, which dew up as readily as the main optic and are often forgotten.
  • Power distribution: Dew heaters draw significant current, and a distribution box sized for the total load prevents voltage sag affecting the mount.
  • Desiccants: Control moisture inside stored equipment, where slow condensation cycling causes long-term damage.

Why Choose David Astro for Dew Control

We observe through Canadian humidity and Canadian cold, which are different problems requiring different amounts of power.

  • Power budgeted for the whole night: We total heater draw against your supply capacity, because a battery that runs the mount for eight hours may run mount plus heaters for three.
  • Sized to aperture: Strap length and wattage are matched to your specific optic. An undersized strap runs at full power and still loses; an oversized one wastes battery and can induce tube currents.
  • Controller recommended, not optional: Running heaters unregulated wastes power and can degrade seeing through the tube. We recommend a controller with any heater purchase.
  • Authorized dealer: Genuine products with manufacturer warranty, in Canadian stock.
  • Ships from Canada: No duties or brokerage fees on Canadian orders.

Dew Control in Canada — Frequently Asked Questions

Is a dew shield enough on its own?
Often for refractors, which have a recessed objective and can use a long shield. Schmidt-Cassegrains, with the corrector at the front, almost always need a heater as well.
How much power do dew heaters draw?
Enough to matter — a large strap can draw several amps at full output. A controller typically cuts average consumption substantially by pulsing rather than running continuously.
Can I use a hair dryer to clear dew?
It works but is a poor solution. Rapid heating creates tube currents that ruin seeing for a long time afterwards, and the dew returns within minutes. Prevention with a low-power heater is far better.
Do I need dew control in winter?
Yes, and frost is the winter version of the same problem. It forms by the same radiative cooling mechanism and is harder to remove without damaging coatings, so prevention matters more, not less.

Losing nights to dew?

Tell us your aperture and power setup and we will specify heaters, a controller and a shield. In Canadian stock, shipped worldwide.