Houdini 20 coma-correcting eyepiece now available

Houdini Telescopes has officially launched the Houdini 20, a revolutionary coma-correcting eyepiece designed to enhance the observing experience for users of Newtonian telescopes. The first production batch of this highly anticipated product is set to begin shipping worldwide from their shop around April 10. Customers can purchase the Houdini 20 exclusively through the company’s official website, houdinitelescopes.com.

Houdini 20 coma-correcting eyepiece now available: The 20 mm coma-correcting eyepiece ushers in a new era for newtonian telescope users

The Houdini 20 is being offered at an introductory price of approximately $370 for customers within the European Union. For international buyers located outside the EU, the price is about $300, depending on exchange rates and local taxes. Shipping costs are calculated at checkout, and the company encourages potential buyers from unlisted countries to reach out directly for assistance. While the eyepiece is currently available only through Houdini Telescopes' online shop, plans are already in motion to distribute it through resellers later in the year. As the product moves toward its final retail price of around $435, early adopters are encouraged to take advantage of the launch pricing.

Houdini 20 coma-correcting eyepiece specifications

• Focal length: 20 mm
• Apparent field of view: 86°
• Field stop: 30.0 mm
• Optical layout: 8 elements in 6 groups
• Theoretical eye relief (center of field to glass): 20 mm
• Useful eye relief (edge of field to body): 15 mm
• Maximum diameter: 64 mm (2.52 inches)
• Overall height including eyecup: 140 mm (5.51 inches)
• Barrel length: 35 mm (1.38 inches)
• Weight: 570 grams (1.26 lbs)
• Barrel size: 2 inch (50.8 mm)
• Focal point: 2 mm (0.08 inches) above barrel
• Field flatness: Less than 0.7 diopters
• Angular magnification distortion: Less than 2%
• EAN: 5419980565808
   

Houdini 20 and Houdini 12 eyepieces

What makes the Houdini 20 so groundbreaking is its integrated parabolic coma correction. Traditional Newtonian telescopes, especially those with fast optics, suffer from an optical aberration known as coma. This effect causes stars at the edge of the field of view to appear stretched or distorted, which can detract from the clarity and immersion of deep sky observing. Historically, solving this problem has required bulky, expensive, and often finicky coma correctors that must be paired with standard eyepieces. Houdini Telescopes has removed this obstacle by incorporating coma correction directly into the eyepiece itself.

This integrated design means users no longer need to worry about the complex process of positioning and adjusting a separate coma corrector. Observers simply insert the Houdini 20 into their telescope’s focuser, adjust focus as normal, and enjoy a coma-free view. This simplicity and effectiveness represent a significant leap forward in optical convenience and performance.

Optically, the Houdini 20 is designed for excellence. It features a wide, immersive 86-degree apparent field of view that remains well-corrected across the entire frame, even in fast telescopes as fast as f/3. The eyepiece delivers sharp star images from edge to edge, aided by advanced multi-coated optics, high-transmission glass types, and blackened lens edges that work together to maximize contrast and minimize internal reflections. The optical layout consists of 8 elements in 6 groups, configured to offer both flat-field performance and minimal distortion, key attributes for deep sky observation.

Eye relief is another strength of the Houdini 20, offering a comfortable 0.79 inches at the center of the field and about 0.59 inches at the edge. This makes the eyepiece ideal for observers who wear glasses or simply prefer a more relaxed viewing experience. The eyepiece housing is robust yet ergonomic, featuring a rubberized grip, foldable rubber eyecup, and a barrel with safety kerfs that ensure it seats securely in the focuser without tilting or locking awkwardly. A glow-in-the-dark cap not only protects the optics but also displays the focal length for easy identification in the dark.

Physically, the Houdini 20 is thoughtfully engineered. It has a maximum diameter of 2.5 inches and stands about 5.5 inches tall including the eyecup. The 2-inch barrel is roughly 1.4 inches long and is threaded to accept standard filters. Weighing approximately 1.26 pounds, it balances well in most telescope setups, avoiding the nose-heavy issues that plague many larger optical accessories. The focal point of the eyepiece is set 0.08 inches above the barrel, ensuring easy focus acquisition across a wide range of telescopes.

Although optimized for Newtonian telescopes with parabolic mirrors, the Houdini 20 is also compatible with many other telescope designs that operate at f/6 or slower, including long-focus refractors and popular Schmidt-Cassegrain systems. However, it is not recommended for fast optical systems lacking a parabolic mirror, such as f/5 apochromatic refractors, where the built-in coma correction will not be effective and may degrade image quality.

The Houdini 20 is not just a standalone product but the first in a new line of coma-correcting eyepieces. Over the next 18 months, Houdini Telescopes plans to introduce a full series of models ranging from 30 mm to 4 mm. The next model in the series, the Houdini 12, is already in production. A prototype is currently undergoing validation, being tested on a range of instruments including a 43-inch f/3.6, a 25-inch f/5, and an 8-inch f/4 Newtonian telescope, as well as a 6-inch f/8 refractor binoscope and a 4.3-inch f/6 refractor. These rigorous tests aim to ensure consistent high performance across different focal lengths and telescope designs.

In support of their premium optics, Houdini Telescopes also offers an Eyepiece Cleaning Kit that includes ROR Cleaning Fluid, a Neweco microfiber cloth, and a soft brush. This kit is designed to keep the Houdini eyepieces, and any others, in pristine condition for years of regular use.

One of the primary benefits of coma-correcting eyepieces like the Houdini 20 is the elimination of external coma correctors, which often introduce a host of inconveniences and trade-offs. Traditional coma correctors, such as the Televue Paracorr 2 and Explore Scientific HR, are physically large and heavy, adding approximately 1.1 pounds of weight and about 5.5 inches in length to the optical train. This extra bulk can interfere with secondary mirror placement and prevent the use of accessories like filter slides. In contrast, Houdini’s integrated design avoids these complications while maintaining a compact, manageable form factor.

The cost savings are equally compelling. Standalone coma correctors range in price from around $400 to over $1000 depending on the brand and configuration. For example, the Feather Touch SIPS integrated system adds roughly $850 to $1000 to the total setup cost. These funds could be better allocated toward eyepiece quality or other observing accessories. By offering an eyepiece that includes coma correction without the need for additional components, Houdini Telescopes delivers a more affordable, streamlined, and effective solution.

Ease of use is another major advantage. External coma correctors often incorporate helical focusers or tunable tops that must be adjusted manually when switching between eyepieces. This added complexity not only interrupts observing sessions but also introduces potential for mechanical instability. The Feather Touch SIPS addresses some of these issues by eliminating the need to recalibrate, but even that system cannot match the simplicity of an eyepiece that just works right out of the box, no extra adjustments needed.

Focus in-travel is yet another complication associated with traditional coma correctors. These devices typically require at least 0.6 inches of additional inward focus travel, which can push the focal plane farther from the telescope’s main optical axis. This shift may require a larger secondary mirror or compromise the telescope’s fully illuminated field. By integrating the correction into the eyepiece itself, Houdini avoids this problem entirely, preserving the original optical geometry of the telescope.

From an optical standpoint, adding a separate coma corrector introduces more glass elements, typically four or five, to the light path. When paired with premium eyepieces that already include six to ten elements, the total number of surfaces increases substantially. Every glass element slightly reduces light transmission and increases internal scatter, diminishing image contrast and brightness. By combining coma correction and eyepiece optics into a single, optimized unit, the Houdini 20 minimizes these losses and enhances overall performance.

Each Houdini eyepiece is designed in-house using proprietary software that optimizes every aspect of the optical configuration. The result is a series of eyepieces that not only meet but often exceed the performance of high-end setups that require multiple components. Every Houdini eyepiece undergoes individual inspection at the company’s facility to ensure it meets strict optical and cosmetic standards. This attention to detail ensures that each unit performs consistently and reliably for amateur and professional astronomers alike.

Eyepiece cap with glow in the dark focal length

In summary, the Houdini 20 mm coma-correcting eyepiece represents a major breakthrough in telescope accessory design. It simplifies the observing process, reduces the weight and cost of achieving high-quality views, and eliminates the need for additional coma correction devices. With its wide field of view, sharp optical performance, user-friendly features, and competitive pricing, the Houdini 20 stands out as one of the most innovative eyepieces available today. As the first in a planned series of coma-correcting eyepieces, it also sets the stage for a new generation of optical tools that promise to transform how astronomers experience the night sky.

Houdini 20 vs standard 20 mm eyepieces

Buy the Houdini 20 eyepiece