Amongst amateur astronomers, there is often much debate over what the might be the best, affordable, and most versatile imaging camera. We can guarantee that in one telescope gets brought up in every variation of this conversation, and that is the William Optics RedCat 51LX Apochromatic Refractor Telescope. From the sleek crimson shine of the optical tube, to ribbed black grips, to the powerful quadruplet lenses, this telescope is easily one of the best astrophotography telescopes on the market. What’s more is that it is also one of the most affordable, priced at an unbelievably low $823.00. The William Optics RedCat 51LX Apochromatic Refractor Telescope has been awing amateur astronomers since its debut in March of 2019, and has held its ground as one of the best devices for both amateurs and veterans alike.
Even better is that, unlike most apochromatic telescopes, the William Optics RedCat 51LX Apochromatic Refractor Telescope doubles as a visual telescope as well. Its versatility doesn’t end there, as the telescope is also highly suitable for daytime wildlife photography and viewing as well. Though, it is worth mentioning that in order to use the telescope as a visual piece of equipment, you will need to purchase the William Optics 1.25″ 90 RedCat Erecting Prism Diagonal which can accept any one and a quarter inch eyepiece. This truly is one telescope that can do it all, and this flexibility is justification enough for pricing the telescope at a much higher price point. However, this would go against the code of ethics that William Optics holds itself to.
Founded in 1996 by William Yang, William Optics prides themselves on creating high quality and perming telescopes at an affordable price. Their company mantra, “More quality for Less money,” echoes this point. The company continues to surprise with innovative designs that push the limits of what a telescope is capable of, and they continue to keep this high performing quality within the range of affordability for the average amateur astronomer. In the twenty plus years since their founding, William Optics has quickly grown to be one of the most respected manufactures of highly portable, short tube, refractor telescopes in the world.
Superior Petzval optical assembly
The William Optics RedCat 51LX Apochromatic Refractor Telescope features a four element design grouped into three lens positions, and all elements are made with Ohara FPL53 & FPL51 synthetic fluorite glass. This Petzval design allows for light to be taken in by the initial doublet, which provides for low dispersion and correction of spherical aberration. The light path then comes into the supporting two lenses, which correct for astigmatism while working to increase the focal ratio. This allows the William Optics RedCat 51LX Apochromatic Refractor Telescope, which has an aperture of two inches, and a focal length of two-hundred and fifty millimeters, to function with a focal ratio of f/4.9, meaning that this is a fast telescope that can intake light on par with a device with a much larger aperture. The fast focal ratio also enables the telescope to capture movement and detail that outrivals the capabilities of a DSLR on its own, creating a telescope that is optimally suited for wildlife photography as well as astrophotography.
The Petzval design eliminates any worry about chromatic aberration, meaning that your images will not be weighed down by magenta hues around your subjects, and that the optics produce a flat field across the entire field of view. Not having to worry about adding an additional field flattener also means that you won’t have to worry about back focus and spacing. On its own, the optical assembly does a lot of work to produce crystal clear and precise images that are full of contrast and highlight color.
And, with an image circle of forty-four millimeters, this telescope functions with both full frame and crop sensor cameras. This allows for more versatility in your camera and framing options, ensuring that you get the image you want every time.
The William Optics RedCat 51LX Apochromatic Refractor Telescope is also extremely lightweight, weighing in at only two and half pounds. Highly portable, this telescope won’t weigh you down as you travel to locations in the field, regardless of if you’re shooting night time astrophotography or daytime wildlife photography.
Indexed helical focuser and field rotator
The design of the William Optics RedCat 51LX Apochromatic Refractor Telescope favors photographers on the go, as indicated by the easy to use helical focuser and field rotator.
The helical focuser makes it easy to focus your targets either while peering through the focuser or while utilizing a laptop setup, a marked improvement over the traditional rack and pinion focuser seen on most telescopes. The clearly numbered index enables you to keep precise control of your focus settings, further supported by a focus tension ring that allows you to adjust heighten and lower the friction of the focuser to ensure you reach your desired focus setting. You can even use the tension control to lock your focus setting into place. Both the helical focuser and the focus tension control are designed with ribbed black rubber, providing both grip as well as a defined contrast to the sleek crimson shine of the telescope’s beautiful optical tube.
Inspired by the design of luxury watches, the field rotator is clearly marked to every degree and allows you to rotate your telescope and camera with the entire three-sixty degrees of motion. This unique design choice was made in order to make mosaics of large deep sky objects easy. Sectioning of portions of your celestial target are no longer frustrating and complex, and can be accomplished with both speed and precision thanks to this easy to use feature.
Camera sensor tilt adjuster and other accessories
The William Optics RedCat 51LX Apochromatic Refractor Telescope also comes with a number of built in accessories to both simplify the process of imaging your celestial targets, and to amplify the effects within any image you take.
The first of these improvements is the inclusion of a tilt shift adjustor, which allows you to manipulate the orientation of your camera’s senor in relation to the telescopes field of view. This can change the entire plane of focus of your image, allowing you to shift the scale of focus and the depth of field. Tilting the image plane like this can give you more control over your desired amount of blur in the background of your image, a tool immediately useful for wildlife photography.
The William Optics RedCat 51LX Apochromatic Refractor Telescope also includes a built in filter adaptor, adding convenience to the process of changing and implementing filters to your image. There is also the mounting plate, which is an innovating Vixen style dove plate that can be easily flipped over and attach to any Arca-Swiss style photography tripod head, providing for more versatility in your mounting options. The telescope’s modular mounting ring allows you to add a finder scope or guide camera, while remaining sturdy enough to support the weight of your attached DSLR. The telescope also features an extendable dew shield to protect your lens from the elements and eliminate the frustration of photographing in areas with high humidity. The telescope also includes a standard M48 camera mount that functions with almost any T-adaptor, as well as a soft shell carrying case that is padded to protect your telescope during both transport and storage.
One of the more impressive inclusions is the Bahtinov Mask that is integrated into the lens cap. Not only does this aid in focusing, by allowing you to find the perfect focus for pinpoint stars with your DSLR, it is an added convenience as you won’t have to purchase one separately. Unlike most Bahtinov Masks, the one included here features a clear acrylic design rather than the solid opaque typically seen, making it much easier to use.
Features and specifications
- The William Optics RedCat 51LX Apochromatic Refractor Telescope is a wide field quadruplet apochromatic refractor that functions as both an imaging and visual telescope when paired with the William Optics 1.25″ 90 RedCat Erecting Prism Diagonal, and is versatile in its imaging application
- The telescope is lightweight and portable, weighing in at only 2.5 pounds
- The 2” aperture, along with the 250 mm Focal Length, and f/4.9 Focal Ratio allow for superb and sharp wide field imaging of deep sky objects, as well as quick moving wildlife photography
- The telescope features high quality quadruplet lens design features premium multi-coated Ohara FPL53 & FPL51 synthetic fluorite glass that lowers dispersion and eliminates the worry of chromatic aberration and image reflection
- The telescope’s imaging circle of 44 mm ensures that the telescope functions with both full frame and crop sensor cameras
- The telescope includes a built in dedicated corrector, removing the need to purchase a field flattener and guaranteeing crystal clear focus and precision
- The telescope comes with a Vixen style dovetail that can be flipped to function with any Arca-Swiss style photography tripod head
- The telescope includes a unique indexed helical focuser and field rotator to ease focusing and creation of mosaic images
- The telescope comes with built in extendable dew shield
- The telescope features an integrated M48 camera mount
- The telescope comes with a soft carrying case guaranteed to protect your telescope
- The telescope includes a clear acrylic Bahtinov Mask that is integrated into the lens cap
- The William Optics RedCat 51LX Apochromatic Refractor Telescope is backed by Willam Optics’ two year limited warranty
User Reviews
The William Optics RedCat 51LX Apochromatic Refractor Telescope is featured on a number of different retailer sites, including William Optics’ main site, OPT, Highpoint Scientific, and Agena Astro. The telescope has garnered an impressive consumer review score of 5/5 on OPT, and a 4.9/5 on both Highpoint Scientific and Agena Astro.
Users agree that the William Optics RedCat 51LX Apochromatic Refractor Telescope is “a work of art” that is “absolutely worth every penny.” They report that they “love this refractor” as “the quality of construction and finish is outstanding” and that it “was obviously designed by an astrophotographer with evident and careful thought toward imaging convenience.”
One user reports that “the quality and sharpness of [their] deep space astrophotography [has] increased considerably” since using this telescope, thanks to the “high quality optics” which “produces clear images with no coma or color fringing from edge to edge” and “perfectly round stars.” This is thanks to the “Petzval design, [which is] is also very eyepiece friendly.”
Users resoundingly agree that “this lens is all that is advertised.” Users applaud the “camera style focus” that is “easy and reliable to use” and are impressed with “the ease with which [they] can rotate the camera frame” to get just the shot they want. Even better is that the telescope “keeps focus fine throughout the night.”
With this telescope it is “easy to find objects in the sky, since the field of view is wide and forgiving, and the focus is sharp enough to pick up double stars.” Users find that both “the color and clarity of this scope are excellent,” and that the “included Batinov mask makes focusing a breeze.”
Users are impressed with this “amazing little scope,” which “is also very portable.” Many users report that this is the “perfect telescope for wide-field imaging” and suitable for both beginners and amateurs alike.
Of course, as with any product, users have come across some concerns. It should be noted again, that while this telescope is able to function a visual piece of equipment, this will require an additional purchase of the William Optics RedCat Erecting Prism Diagonal, which might turn strictly visual observers off. One user found that the “procedure for swapping the camera adapter for the image erecting prism requires dealing with Allen wrenches and set screws” which overcomplicated the process, and made it difficult to perform under the dark of the night sky. Users also warn that you should “not lock the focus too tight”, as “you will not be able to unlock it during the morning” after cold nights due to slight expansion of the mechanics.
To summarize, the William Optics RedCat 51LX Apochromatic Refractor Telescope is a prime example of the William Optics’ company pledge to produce high quality imaging refractors at a price that is accessible to the average consumer. Since it hit the market in March of 2019, this telescope has proved itself to be one of the best imaging telescopes available for both astrophotography and wildlife imaging, and because of this they can sometimes be hard to find. The quadruplet optics, along with the advanced features, such as the included Bhatinov Mask, the helical focuser, the field rotator, and the integrated dew shield, make this telescope perhaps the most capable imaging scope on the market. It is extremely fast, with an f/4.9 focal ratio, and highly lightweight and portable, making it the perfect grab and go telescope for in the field astrophotography and wildlife photography. Based on consumer feedback, it is easy to see that this one telescope that has left each and every user impressed.
Link to Official Store and Page for the William Optics RedCat 51LX
Comparable telescopes
While we endorse the William Optics RedCat 51LX Apochromatic Refractor Telescope, you might also consider the following products:
- Sky-Watcher EvoStar 72 72mm APO Refractor Telescope
- SharpStar 61 EDPH II APO Refractor Telescope
Additional accessories
Here are some accessory suggestions that will improve your experience with the William Optics RedCat 51LX Apochromatic Refractor Telescope:
- William Optics CatEye 10mm Eyepiece
- William Optics 1.25″ 90 RedCat Erecting Prism Diagonal
- William Optics Cat Series Saddle Handle Bar
