Radian Raptor 61 Review by Zane Landers

The Radian Raptor 61 is sold for $1,000 and is advertised as a revolutionary telescope. In reality, it is merely a rebadged copy of the SharpStar 61EDPH, which is sold for half the price, with an included reducer/flattener and some gimmicky features.

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Review

The Radian Raptor 61 is sold for $1,000 and is advertised as a revolutionary telescope. In reality, it is merely a rebadged copy of the SharpStar 61EDPH, which is sold for half the price, with an included reducer/flattener and some gimmicky features. Adding to that, a scope such as the 61EDPH sits in an odd niche in astrophotography – the short focal length is comparable to a telephoto lens, but the scope is so heavy that it needs an HEQ5-class mount to be used – at which point you might as well go for something with more aperture and focal length….

Image Courtesy of Radian Telescopes

Optics

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61mm (2.4”) Aperture

275mm Focal Length

f/4.5

Triplet Optics

The Raptor 61 is a 61mm (2.4”) f/5.5 triplet refractor that uses extra-low dispersion or ED glass in one of its front lens elements. The native focal length is 335mm. The scope is bundled with a 0.8x reducer/field flattener that brings the scope down to f/4.5 and 275mm in focal length, comparable to many telephoto lenses but without the diffraction effects induced by an iris and with better overall correction across the field of view. It should be noted that a 275mm f/4.5 isn’t terribly different from something like the William Optics RedCat at f/4.9 and 250mm focal length, and the RedCat can fit on a star tracker or other minuscule mount as opposed to the Raptor, which is an absolute tank that really needs to be put on an HEQ5-class mount.

The included field flattener works well, and screws directly into the back of the telescope optical tube.

Courtesy of Trevor Jones of AstroBackyard, Canon EOS Ra, The Heart & Soul Nebulae

Courtesy of Trevor Jones of AstroBackyard, Canon EOS Ra, The California Nebula

Mechanics

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Refractor

Astrograph

Included 0.8x flattener / reducer

Dual speed 2” focuser

The Raptor uses a 2.5” dual-speed rack-and-pinion focuser which can be rotated and includes a “filter drawer” for installing a broadband light pollution filter. The tube rings are hexagonal and OPT glamorizes their supposed advantages over round rings; it’s essentially a gimmick. You also have to unlatch both rings to rotate and slide the tube around as opposed to the traditional clamshell or built-in foot designs that dominate small refractors

You do get a pair of dovetails – one Losmandy and one Vixen-style rail – which is helpful for attaching the scope to a mount and accessories to the top, but there’s no standard finder/guide scope shoe and putting a dovetail on the top sacrifices the ability to attach a carry handle.

Image Courtesy of Radian Telescopes

The dew shield on the front of the scope is an industry standard for almost any refractor made after 1950, and the included carry bag is acceptable but not something we would entrust thousands of dollars worth of equipment to.

OPT/Radian make a real effort of trying to sell you on additional gimmicky stuff to go with your Raptor too – such as an $11 “polishing cloth” that is produced for pennies, a green laser pointer marked up by about 1000% of their wholesale price, and a $500 motor focuser, which is nothing to write home about compared to the much cheaper ZWO EAF motor focuser. 

Image Courtesy of Radian Telescopes

Mounting Options

The Raptor technically weighs a mere “4 pounds” – but add a camera and autoguiding setup, not to mention cables, dew heaters, and a motor focuser, and you’ll be lucky to come in at under double that. A star tracker-sized mount like a Star Adventurer or Skyguider Pro is going to struggle to produce even a handful of acceptable images. The EQ3-class mounts like the Sky-Watcher Star Adventurer GTi are up to the task of holding the Raptor – barely – but for best results, an HEQ5, Advanced VX, or similarly bulky mount is needed if you enjoy taking long exposures and not having to discard frames. Thus, you are easily looking at spending well over double the price of the base Raptor telescope itself to get started before you even start thinking about a camera, guiding, motor focuser, or premium software. 

What Can You See?

The Raptor 61 isn’t ideal for visual astronomy due to its cost, fast focal ratio, and minuscule aperture. However, if equipped with a good star diagonal and eyepieces, it’ll show you the phases of Mercury and Venus, the moons of Saturn and Jupiter, Saturn’s rings, and Jupiter’s cloud belts, along with a wealth of detail on the Moon. However, the ice giant planets are merely star-like dots, with no features, obvious disk, or moons visible. The Raptor can give you pleasant views of open star clusters, but again, it’s hardly the best scope for the task. Globular clusters and galaxies are faint unresolved fuzzy patches and planetary nebulae are simply too small and dim to observe well.

Drawbacks

Expensive

As previously mentioned, the Raptor’s high price compared to identical telescopes sold by brands like Teleskop-Express and Sharpstar makes it essentially a pointless buy, and due to the weight of the triplet optics, it ends up needing a big mount which can and really should be used with a larger optical tube with more focal length. If you want a small, portable scope for wide-field or beginner astrophotography, a RedCat or a 60-66mm ED doublet is cheaper, lighter, and generally easier to work with than a bulky triplet like the Radian Raptor 61. 

Value

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Conclusion

The Radian Raptor 61 certainly isn’t a bad telescope for astrophotography, but a 61mm triplet refractor is an odd beast and cheaper, identical models exist elsewhere. The Raptor is seriously marked up and it is generally sold with advertising fluff rather than simply standing as a good scope on its own; other manufacturers don’t generally rave about how they invented such common devices as a dew shield and tube rings or how convenient it is that you don’t have to spend a few minutes shopping for a reducer separately. 

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