CELESTRON 94050 Dew Heater Ring User Manual

CELESTRON 94050 Dew Heater Ring

The Celestron Dew Heater Ring provides the best dew prevention solution for your Celestron Schmidt-Cassegrain (SCT), EdgeHD, or RASA telescope. It integrates directly into the optical tube assembly, and “lives” with the telescope so you’ll never forget it or need to uninstall and reinstall it. Additionally, since the heating element is in direct contact with the Schmidt corrector lens, it provides more effi cient power usage than heating strips that wrap around the exterior of the telescope tube. For best power effi ciency during use, there is also an integrated thermistor in the ring. When used with one of the optional Celestron Smart DewHeater Controllers, the thermistor provides data to the controllers to apply just the right amount of power to keep the corrector free from dew all night while minimizing power usage.
Please read through this entire manual before attempting to install or use the dew heater rings.

DEW HEATER RING COMPATIBILITY

after 2006, all 8” EdgeHD, all

RASA 8

94052| Dew Heater Ring, 9.25”| All 9.25” Schmidt-Cassegrain, all 9.25” EdgeHD
94053| Dew Heater Ring, 11”| 11” Schmidt-Cassegrain produced

after 2006, all 11” EdgeHD, all

RASA 11

94054| Dew Heater Ring, 14””| 14” Schmidt-Cassegrain produced

after 2006, all 14” EdgeHD, all RASA 36cm

For 8”, 11”, and 14”, if you are unsure when your Schmidt-Cassegrain telescope was produced, refer to the FAQ on the Dew Heater Ring product webpages at celestron.com.

PARTS LIST

INSTALLATION

WARNING: The dew heater ring comes in direct contact with the telescope’s Schmidt corrector lens and provides mechanical support for this optical element. When installing the dew heater ring, it will be important not to change the position or orientation of the Schmidt corrector, or optical performance may be affected. There are 4x set screws that support the edge of the corrector. Do not attempt to make adjustments to these screws or optical performance may be affected. Additionally, be very careful not to damage the Schmidt corrector itself when installing the dew heater ring; make sure you are in a well-lit room and are focused on the task at hand before you attempt to install the ring.

1. Orient your optical tube assembly (OTA) vertically, so that the front of the telescope is pointing straight upward. We recommend using your telescope mount to achieve this orientation. This may require shortening the tripod legs for a workable height (for German EQ mounts, see Figure 2) or removing the entire mount and OTA from the tripod (for fork-mounted telescopes, see Figure 3). It is very important that the OTA is pointing vertically during installation. This will help ensure the optics do not shift or move during installation.

2. Remove the dust cover and any dew shield connected to the optical tube.

3. Use the included paper installation shield to cover the optics during dew heater ring installation. This will help protect the Schmidt corrector lens from inadvertent scratching, fi ngerprints, and dust. Place the paper shield over the Schmidt corrector so the secondary obstruction fi ts within the central hole in the shield (Figure 4).

4. Use a Phillips-head screwdriver to carefully unthread and remove the screws that connect the telescope’s corrector retaining ring to the front cell (Figure 5). For 5” through 9.25” telescopes, there will be six screws to remove. For 11” and 14” telescopes, there will be eight screws to remove.

5. Carefully remove the retaining ring from the telescope. Also remove the gasket material ring underneath the plastic retaining ring.(Figure 5b)
   For 8”, 9.25”, and 11” telescopes only, there are two pins on the interior of the front cell that are for the telescope’s lens cap. These will interfere with removing the retaining ring. Slightly bend the plastic ring to provide clearance with one of the pins so you can remove the ring.

6. Carefully place the dew heater ring where the retaining ring was previously. Orient the dew heater ring so that the compliance labeling on the ring is just to the right of the telescope’s dovetail when looking at the front of the tube (see Figure 6). Line up the through holes in the dew heater ring with the threaded holes in the telescope’s front cell.
   For 8”, 9.25”, and 11” telescopes only, the pins on the interior of the front cell will interfere with installation of the of the aluminum ring, but there is a notch in the ring’s perimeter to account for this. First, place the outer edge of the ring under one of the pins. Then, rotate the ring until the notch lines up with the other pin (Figure 6b), and you can now seat the ring onto the lens cell. Once seated, rotate the ring until it is oriented as indicated in Figure 6.

7. Reinstall the screws removed previously. Only fi nger tighten initially. Then, when tightening the screws with your Phillips-head screwdriver, use a cross pattern among the screws (Figure 7). Only lightly tighten screws at fi rst, so the head of the screw is just above the retaining ring. When all screws are lightly installed, begin fi nal tightening of the screws, again in a cross pattern. Make sure the screws are fi rmly tightened but do not overtighten them or you may strip the threads.

8. Remove the paper installation shield. Installation is now complete.
   When the dew heater ring is not in use, the power jack and thermistor jack stay clipped to their plastic storage clips which are connected to the ring itself (Figure 8). When in their storage clips, the telescope’s dust cover can be placed on the front of the tube without interference from the jacks.

STAND˜ALONE OPERATION

The simplest way to use the dew heater ring is to connect a 12V DC power supply to the ring’s power jack.

1.  Remove the power jack from its storage clip on the ring and place the jack into the included cable management clip (Figure 9).

2. Attach the cable management clip to the front cell of the telescope near where the jack connects to the heater ring (Figure 10). When doing this, avoid pulling on the jack’s cable, which puts strain on its connection to the heating circuit, and with enough force could cause cable damage. The cable management clip holds the jack securely to the front cell of the optical tube in a convenient position and prevents pulls on the jack’s cable when in use.

3. Now, just plug your 12V DC power source (5.5mm/2.1mm barrel plug, tip positive) into the heater ring’s power jack, and the ring will begin to heat up.
   When used in this “stand-alone” operation, the heater ring’s thermistor is not used, and the ring always operates at full power. This provides the highest level of dew prevention but is not the most effi cient use of power to keep the optics clear.
   At full power, the dew heater rings draw the following amount of current:Dew Heater Ring| Max Current Draw
   ---|---
   5”| 0.6 A
   6”| 1.0 A
   8”| 1.7 A
   9.25”| 2.0 A
   11”| 2.5 A
   14”| 4.4 A

Make sure your 12V DC power source can deliver at least the maximum amount of current draw, otherwise the ring may not heat up enough to prevent dew from forming on the corrector during heavy dew conditions.

When you are done for the night

1. Unplug the power source from the ring’s power jack.
2. Remove the power jack from the cable management clip and place the jack into its storage clip on the dew heater ring.
3. Remove the cable management clip from the telescope. We recommend storing this clip in your eyepiece or equipment case.
4. Now place the telescope’s dust cover on the front of the optical tube.

USAGE WITH CELESTRON SMART DEWHEATER CONTROLLERS

For the most effi cient power usage while keeping your optics free from dew all night, we highly recommend using the dew heater rings with the Smart DewHeater Controllers. These controllers utilize the ring’s built-in thermistor to provide just the right amount of heat to prevent dew based upon the ambient temperature, ambient humidity, and temperature of the Schmidt corrector.
To use the dew heater rings with the Smart DewHeater Controllers:

1. Remove both the ring’s power jack and thermistor jack from their storage clips on the ring and insert them into the cable management clip (Figure 11).

2. Attach the cable management clip onto the front cell of the telescope near the jacks as indicated previously (Figure 12). Be sure not to pull on the cables too hard when doing this.

3. Connect the heater ring’s power jack to one of the Smart DewHeater Controllers heater output ports using the included extension cable.
4. Use the thermistor extension cable that comes with the Smart DewHeater Controllers to connect the heater ring’s thermistor jack to the corresponding thermistor port located on the controller box under the heating port that the ring is now connected to.
   The dew heater ring is now ready to be used with the Smart DewHeater Controllers. For more information on powering and operation of the Smart DewHeater Controllers, refer to the instruction manual that comes with the controller.
   The dew heater rings are also generally compatible with third party dew heater controllers. Use the included extension cable to connect the dew heater ring’s power jack to the controller’s heater output port.
   NOTE: The dew heater ring’s integrated thermistor is generally NOT compatible with 3rd party dew heater controllers. To utilize “smart” functionality for most effi cient power usage, you will need a Celestron Smart DewHeater Controller.

USE WITH DEW SHIELDS

To achieve the highest level of dew prevention, use the heating rings in conjunction with a dew shield. While not mandatory, a dew shield will cut down on the amount of power the dew heater ring needs to use to keep the optics clear of dew. This will result in even better power effi ciency.
The Celestron Aluminum Dew Shields have a cable management clip built-in so that they can work seamlessly as a system with the dew heater rings (Figure 13). If you regularly observe in very heavy dew conditions, we recommend using both a heater ring and dew shield, especially with the larger aperture 11” and 14” models.

IMPORTANT NOTE : Be sure to fi rst remove the dew heater ring’s jacks from the integrated clip in the Aluminum Dew Shield before attempting to remove the dew shield from the telescope. Otherwise, you can damage the jacks and the heater ring can become inoperable.

SPECIFICATIONS

connector, tip positive
Power jack extension cable| 6” long, 12V DC, 5.5mm/2.1mm barrel connector on one end, male RCA connector on other end, tip positive, only needed for use with optional dew heater controllers
Thermistor jack| 2.5mm audio jack, compatible with Smart DewHeater Controllers for most efficient power usage

©2022 Celestron. • Celestron and Symbol are trademarks of Celestron, LLC.
All rights reserved. • Celestron.com • 2835 Columbia Street, Torrance, CA 90503 USA celestron.com/pages/technical-support
(Products or instructions may change without notice or obligation.)
Designed and intended for those 14 years of age and older.

FCC

FCC NOTE: This equipment has been tested and found to comply with the limits for a Class B digital device, pursuant to part 15 of the FCC Rules. These limits are designed to provide reasonable protection against harmful interference in a residential installation. This equipment generates, uses, and can radiate radio frequency energy and, if not installed and used in accordance with the instructions, may cause harmful interference to radio communications. However, there is no guarantee that interference will not occur in a particular installation. If this equipment does cause harmful interference to radio or television reception, which can be determined by turning the equipment off and on, the user is encouraged to try to correct the interference by one or more of the following measures:

• Reorient or relocate the receiving antenna.
• Increase the separation between the equipment and receiver.
• Connect the equipment into an outlet on a circuit different from that to which the receiver is connected.
• Consult the dealer or an experienced radio/TV technician for help.

celestron.com/pages/warranty

References

• Celestron - Telescopes, Telescope Accessories, Outdoor and Scientific Products
• Technical Support | Celestron
• Warranty | Celestron

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