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ZWO 1.25" Atmospheric Dispersion Corrector # ADC

4.9 (7 Reviews) Read Reviews Write Review
Brand ZWO Astronomy Cameras
Part Number ZWO-ADC
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Product Info

Manufacturer Description

VOTED A "HOT SKY PRODUCT - 2017" BY SKY&TELESCOPE MAGAZINE!

1. The Problem of Atmospheric Dispersion

Like a big glass prism or lens, the Earth's atmosphere refracts or bends the light from stars or planets on its way to a telescope, and it bends light of different colors by slightly different degrees. This effect is called atmospheric dispersion and it results a greater refraction of blue and green light than red light, for example. It's the same effect that causes the well-known 'Green Flash' on the upper edge of the Sun as it sets below the horizon.

Of course, when you're imaging the planets or the Moon, especially when their light travels through the thick atmosphere above the horizon, dispersion is a big problem. If you're doing color imaging of planets low near the horizon, dispersion results in color fringing of the image. It can be removed with processing but at the cost of detail and resolution. If you image in monochrome with separate LRGB frames, you still suffer from atmospheric dispersion in the luminance frame. Even visual observers can notice the effects of dispersion when observing planets and the Moon low on the horizon where the effects of atmospheric dispersion are greatest.

2. Dispersion Compensation for Astroimagers and Visual Observers

The ZWO Atmospheric Dispersion Corrector (ADC) is an ingenious device that compensates for the effects of atmospheric dispersion. The ZWO ADC uses a pair of prisms that can be precisely adjusted with manual levers to apply the opposite dispersion induced by the atmosphere. The device then directs all colors of light to re-converge at the focal plane. The adjustment can range from null (no correction) to maximum refraction suitable for correcting for the well-understood effect of atmospheric dispersion at a range of altitudes above the horizon.

The effect of using the ZWO ADC? Greatly improved image resolution and detail for both imagers and visual observers, even when the planet is just above the horizon. You no longer need to wait hours for the planet to get higher in the sky during the night, or years for the planet to reach a more favorable opposition.

3. Designed for Ease of Use and Optimum Image Quality

The ZWO Atmospheric Dispersion Corrector consists of three pieces. The main body holds the corrective prisms and adjustment levers. The two lever slots overlap to allow both levers to move together over a wider range. A 1.25"; barrel adapter for the bottom of the main body and a 1.25" adapter for the top of the body each mount into the female threads on the body to accept the camera/eyepiece and Barlow. The ZWO ADC works best at large focal ratios, so you get optimum results when you place the device between a Barlow lens and the camera or eyepiece.

The body of the ADC also has a white locking screw on the scale to mark the null point about which the levers are rotated to get the optimum correction of a given planet at a given altitude. This allows you to finely position the null point without having to rotate the body of the ADC. The levers also have an adjustable frictional resistance for ease of use.

The prisms in the ZWO ADC have a 2° deviation angle and are made from H-K9L (Schott BK7) glass with surfaces polished to 1/10 wave accuracy. All optical surfaces are AR-coated to ensure >98% transmission over the visible spectrum.

Priced at a fraction of competing ADC solutions, the ZWO Atmospheric Dispersion Corrector is one of the few devices available to counteract the distorting effects of our atmosphere. Designed by amateur astronomers for amateur astronomers, the ZWO ADC helps you extract maximum detail when observing or imaging the Moon and planets.

Reviews

4.9 (Based on 7 Reviews) 100% of reviewers recommended this product.
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    1. Guest

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      Review by Gerard
      1561985658
      Jul 1, 2019

      5.0 Works well but beware!

      Pros:

      Cons:

      Comments:

      Works a treat but beware it does magnify the image somewhat.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    2. Guest

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      Review by Jim K.
      1557673365
      May 12, 2019

      4.0 Needs Instructions

      Pros:

      Cons:

      Comments:

      Eyepieces typically come without instructions, and so does the ZWO ADC. However, this is not good because although ADC operation is straightforward, it it not intuitive, which may cause frustration. Here are some reasons for ADC online research by a buyer, given there is no manual provided:

      Evidently, there are "right-hand" and "left-hand" versions of the ZWO ADC, which requires some experimentation to determine the orientation of the prisms to the rotation arms for correct operation.

      The prism orientation must be set relative to the horizon, which is different in a straight-through alt-az refractor/SCT and a reflector, when using a GEM, and/or when using a diagonal. Also, prism orientation may need periodic resetting and/or adjustment during the session.

      The prisms refract the view to correct color dispersion, resulting in the moving the object vertically and thus off-center, thus requiring telescope movement to recenter the object, depending on the amount of prism correction needed. And the amount of correction may vary during the session.

      Similar to using a colored planetary filter, deciding when to use the ADC on an object depends on several factors, yet there is no guidance provided with either item. For an ADC the factors include: position in the sky (elevation), brightness, magnification and focal ratio, and any filtration being used, as well as user preferences.

      Doing a websearch results in finding a simple manual/quickguide on the ZWO website and on other distributor websites, as well as detailed reviews that also mention how to use an ADC. I downrated this item one star because it is shipped without instructions or guidance, nor does Agena's website provide them.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    3. Guest

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      Review by Tim K.
      1536319243
      Sep 7, 2018

      5.0 ASI ADC

      Pros:

      Cons:

      Comments:

      Great product shipped fast no issues

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    4. Guest

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      Review by SHENG C.
      1535598114
      Aug 29, 2018

      5.0 Easy to use and works

      Pros:

      Cons:

      Comments:

      Easy to use and works great

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    5. Guest

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      Review by Robert B.
      1527347358
      May 26, 2018

      5.0 Required for Planets and Astrophotography

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      Planets and very small DSOs require a lot of magnification. At these magnifications, the chromatic aberration of the atmosphere (called dispersion) comes into play, especially for objects close to the horizon. Atmospheric dispersion makes the top and bottom of the planets appear red and blue. An Atmospheric Dispersion Corrector allows the astronomer to reverse the dispersion to remove the red and blue aberrations, and allow a sharper view or photograph. The top and bottom of the ADC can be removed to allow it to be added to a T2 optical chain. The level is also a nice touch that facilitates correct alignment of the prisms. I am really surprised that more companies don't offer these. Hats off to ZWO for offering it, and at such a low price!

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    6. Guest

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      Review by James G.
      1495651832
      May 24, 2017

      5.0 ZWO ADC

      Pros:

      Cons:

      Comments:

      Really works! FireCapture 2.5 has an excellent feature for adjusting RGB.

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

    7. Guest

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      Review by Leandro C.
      1482595217
      Dec 24, 2016

      5.0 Works great !

      Pros:

      Cons:

      Comments:

      Works great !

      Bottom Line: Would you recommend this item? Yes
      Was this review helpful? Yes / No

      This review was provided courtesy of AgenaAstro.com

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      Specifications

      Manufacturer ZWO Astronomy Cameras