Radian Raptor 61 Review
The Radian Raptor 61 is a triplet apochromatic refractor telescope for astrophotography. It features a compact design with features custom-suited for wide-field, deep-sky astrophotography.
Since the Raptor arrived in September, I have taken some of my best astrophotography images to date with it. In this review, I’ll share all of the image examples I have collected since the prototype arrived at my door.
This compact telescope was designed for astrophotography with a camera attached, not visual observations through an eyepiece. If you’re interested in taking pictures of deep-sky objects in space, a wide-field imaging refractor telescope is one of the best options available (especially if you are new to the hobby).
At only 4-pounds, the Raptor 61 is suitable for portable, lightweight star trackers such as the iOptron SkyGuider Pro, or Sky-Watcher Star Adventurer. Even after adding a small autoguiding system to the mix, you will still sit well below the 11-lb maximum payload capacity of the most popular star tracker mounts.
This telescope is perfect for those that capture their astrophotography images with a DSLR/Mirrorless camera, or a dedicated astronomy camera. The large image circle (44mm), built-in rotator, and filter vault make capturing your next deep-sky project a painless experience. I enjoy pairing my Canon EOS Ra full-frame astrophotography camera with the Radian Raptor 61 most.
IC 1396 captured using the Radian Raptor 61 and Canon EOS Ra. Trevor Jones.
The Orion Nebula in H-Alpha. Starlight Xpress Trius 694 Mono CCD + Raptor 61.
In February 2020, I spoke to the CEO of OPT (Dustin Gibson) about the possibility of designing an “AstroBackyard signature series telescope“. The idea was to create a beginner-friendly astrophotography telescope that skipped over as much frustration as possible.
Countless phone calls, emails, sketches, and mock-ups followed this conversation, and eventually, the Radian Raptor 61 emerged. You may be interested to know that our original idea included the AstroBackyard branding on the scope and even an actual signature.
In the end, we decided that there were just too many people that didn’t care/know who I was!
I was adamant about building a wide-field, compact triplet that would allow beginners to experience positive results, right out of the gate. I chose the specs that I felt were most important for my personal astrophotography needs, and the team at OPT executed the specifics of that plan in terms of manufacturing a functioning prototype.
The final result was a sleek matte-black triplet refractor with a focal length of 275mm at F/4.5. Pride and accomplishments aside, I believe that this telescope is a serious contender for the best compact astrophotography telescope on the market.
The following video helps explain how the development of the Radian Raptor 61 materialized over time.
Radian Raptor 61 Review
The Radian Raptor 61 was designed to be the ultimate portable astrophotography telescope, and I believe it lives up to this description. There are other great refractors in this category, of course, but none quite like this F/4.5 triplet APO.
The Raptor 61 weighs just 4 pounds with the included mounting rings, meaning that it can be used on a portable star tracker mount or modest equatorial telescope mount with ease.
The Raptor is similar in size and profile to a telephoto camera lens, but with the added modularity of a dedicated astrograph. Mounting a guide scope, attaching and focusing your camera, and framing your deep-sky subject are all extremely easy tasks on the Raptor 61.
I have found myself reaching for the Radian Raptor 61 first when my time under a clear sky is limited. In fact, I can keep the entire imaging setup intact (including the equatorial mount), and simply carry the rig in and out of the garage at a moment’s notice.
View Complete Specs and Order from OPT.
The Radian Hex Rings feature a robust locking mechanism that reminds me of a high-end watch. These rings were specially designed for the Radian Raptor 61 by Optec, and is probably the first thing you’ll notice when you see this telescope.
The rings grasp the telescope securely, and the tension of the rings can be adjusted using a tiny Allan key if necessary. The rings include soft padding on the inside to protect the matte black finish of the optical tube.
The rings also include and an ingenious slot to run your cabling along the base of the dovetail. You can channel the cords to a single source at the back of the telescope.
This is handy when wrapping a dew heater band around the dew shield of the Raptor 61, and a guide scope on top. You’ll likely leave the dew heater band on the telescope at all times when not in use, and simply connect the RCA plug to your dew heater controller before you start imaging.
Here’s a look at my camera bag when I travel with this scope. I keep the camera in the bag as well, along with the guide scope mount and t-ring. You’ll notice I also leave the Canon EF-EOS R adapter on the camera body at all times.
A look into my camera bag.
For me, the best part of the hex ring design is the ability to easily mount the Radian Raptor 61 to the dovetail, and mount a guide scope on top. This isn’t necessary to image with the Raptor 61, but for those shooting exposures longer than 3 minutes, it’s a logical next step.
The standard thread size allows you to mount your existing guide scope bracket on top of the Raptor. I mounted my William Optics 50mm guide scope rings securely to the hex rings for autoguiding.
The Andromeda Galaxy. Radian Raptor 61 + Canon EOS Ra. Trevor Jones.
Adding a small 50mm guide scope adds a bit of weight to the overall imaging setup, but it is well worth it in my opinion. The ability to autoguide exposures to 5-minutes in length (with dithering) is handy for deeper projects.
My best images with the Radian Raptor 61 were created by using 5-minute exposures at ISO 3200 with the Radian Triad Ultra filter in place. I’ve also used a dedicated astronomy camera with this telescope (ZWO ASI294MC Pro), but I think the Raptor 61 is best enjoyed when paired with a full-frame sensor.
I expect others to pair a monochrome dedicated astronomy camera and narrowband filters to the Raptor 61 to create detailed wide-field portraits of the night sky. To date, I have only captured images in one-shot-color with this telescope.
Raptor 61 Key Features
This telescope aims to make the process of getting up-and-running under a clear night sky as painless as possible. You do not need to go looking for a suitable mounting plate that allows you to balance your setup, or find a matching reducer/flattener to flatten the field of view.
The telescope is ready for you to attach your camera (with the correct spacing), right out of the box. You can thread your favorite 2″ light pollution filter into the filter vault, and be on your way. The attention to detail towards the needs of deep-sky astrophotographers is overwhelmingly evident with this package.
- Ultra-portable astrophotography telescope
- 275mm focal length at f/4.5
- Apochromatic Triplet Optics
- Radian Hex Rings with integrated cable management channels
- Full-frame image circle
- Field corrector built-in
- 4″ V-style dovetail & Radian 6.5″ universal D-style plates included
- 10:1 factory-tuned rack & pinion focuser
- 2″ Filter Vault for light pollution/narrowband filters
- Built-in 360º rotator
- Radian padded-insert travel backpack
- Built-in retractable dew shield
- Optional automated focuser upgrade available
The cost of this telescope seems to be a sore spot for some folks, at $999 USD. Personally, I think the price is competitive when you add in all of the extras like the premium rings, dovetails, and built-in corrector.
The world of photography and optics is expensive in general, and I believe anyone that’s invested in quality camera lenses will be less-shocked at the sticker price of this telescope. But don’t get me wrong, $1000 is a lot of money, and you’ll need to justify the expense to yourself (and possibly your spouse) before taking the leap.
With that being said, if you use the telescope almost every clear night over the next 5 years, was it a waste of money? Or did it pay you back ten-fold? (Feel free to use this line on your significant other).
First Impressions and Early Results
When the Radian Raptor 61 first arrived, it came inside of the Radian branded camera bag. I immediately noticed the stocky weight of the optical tube, and quickly mounted the telescope to the included Radian hex rings.
The package I received was a prototype and did not include the bonus items that others will enjoy. This includes the beautifully designed box with the phrase “For those who collect light in the dark“. And for those wondering, yes, that was the phrase I chose.
- Telescope: Radian Raptor 61
- Camera: Canon EOS Ra
- Filter: Radian Triad Ultra (2″)
- Mount: Sky-Watcher EQ6-R Pro
- Guide Scope: Starfield 50mm Guide Scope
- Guide Camera: ZWO ASI120MM Mini
- Accessories: Pegasus Astro PBB, Dew Heaters
Note: For my Andromeda Galaxy image, I used the same setup, but without the Triad Ultra Filter.
You’ll need to remove the protective cap on the interior of the Raptor 61 that covers the built-in reducer/corrector lens. This may throw you off at first, as you will not be able to look through the optical tube until it is removed.
I attached my Canon EOS Ra camera to the Raptor 61 using a standard Canon T-ring. You simply need to secure your camera to the M48 threads of the spacing tube at the imaging end of the scope.
The 10:1 rack & pinion focuser is robust and buttery smooth. It is one of my favorite features of this telescope because it is critically important for deep-sky astrophotography. The locking screw does not shift the image either, which again, shows you how much attention was given to the overall user experience of this scope.
The first image I captured with the Radian Raptor 61 was the Heart and Soul Nebulae region. I managed to collect 6.4 hours of total exposure on this subject using the Canon EOS Ra camera and Triad Ultra filter.
Heart and Soul Nebulae. Radian Raptor 61 + Canon EOS Ra.
By the time the first 5-minute exposure finished, I knew that this telescope would be very popular in the astrophotography community. Seeing a large nebula region appear on the screen at a massive 275mm of focal length is an experience like no other.
The William Optics RedCat 51 offers a similar feeling, but the added aperture and slight focal length increase of the Raptor 61 make a surprisingly noticeable difference. Don’t get me wrong, I adore my RedCat, but I believe the difference in images justifies a clear line of separation between the two.
Not only did the F/4.5 optics gather enough light to reveal faint areas of the nebulae in 5-minutes, but the entire image was extremely detailed and sharp across the majority of the frame. I did see some elongated stars at the very edges of my full-frame image, but I believe this was because of the shallow Canon T-Ring I was using on the camera.
Depending on the camera you pair with the Raptor 61, you should see a crisp image edge-to-edge out of the box with the standard spacing provided on the scope. To slightly increase the spacing, you have the option of threading on a standard 48mm extension tube between your camera and the threads at the end of the Raptor.
Those attaching a DSLR camera to the Raptor 61 will enjoy a near-perfect spacing for a completely flat image out-of-the-box. If you’re using a dedicated astronomy camera such as the ZWO ASI294MC Pro shown below, you may need to make some slight tweaks to get the spacing just right.
A ZWO ASI294MC Pro Camera attached to the Radian Raptor 61.
The combo shown above allowed me to collect the widest field-of-view I’ve ever had with my ZWO camera. I chose to photograph the Lobster Claw Nebula with this setup and I am very happy with the resulting image.
It’s safe to say that unless you’ve attached your dedicated astronomy camera to a camera lens using a specialized adapter, the field-of-view on the Raptor 61 (275mm) will be your widest yet. Image/Pixel scale will come into play here, but no matter which camera you use, you can expect an extremely sharp image at this magnification.
I am sure many people will use the Raptor 61 with their one-shot-color and mono ZWO cameras, and I think you will be quite happy with the creative images possible using this combo.
The Lobster Claw Nebula. ZWO ASI294MC Pro + Radian Raptor 61.
Among the many “controversial” subjects that forum members and Facebook group users chose to focus on, was the glass material used on the Radian Raptor 61. Heated discussions took place on Cloudy Nights about whether the Raptor 61 used FPL-53 glass or not.
I believe this thread may even still be alive if you’ve got a few hours of free time. I have no idea what glass type the factory uses, in this design. If this is a pivotal factor in your telescope buying decision, then you will likely have a hard time justifying the purchase of a Radian Raptor 61 (or a Sky-Watcher Esprit 150 for that matter).
I am not going to pretend to be an expert in optical design, but I can tell you that the apochromatic lens design of this telescope has been carefully designed to meet the highest imaging standards of today’s astrophotographers.
My personal results with this telescope should help put your mind at ease about image quality, but I have a feeling that any uncertainly will be further addressed when others begin to share their images with this scope.
With the correct spacing and no issues with tilt in your imaging train, you should be able to achieve an image field that is completely flat and free of coma and chromatic aberration.
As I mentioned in my video, I did experience some coma at the very edges of my full-frame images. This not an issue for me, nor was it anything I haven’t seen before with my wide-field imaging refractors.
Electronic Focuser Upgrade
Although the package I received included the optional motorized focuser, I have only ever used the Raptor 61 with the manual focuser. Although I have not tapped into the automated focusing system via ASCOM for this scope, I did install the electronic focuser upgrade on the scope to see how it fits.
Installing it to the telescope in place of the focuser knob was a straightforward process with the help of an Allan key. Those that demand critical focus over long periods of time will appreciate this automated option for their system.
The Optional Electronic Focuser Upgrade attached to the Raptor 61.
- Aperture: 61mm
- Focal Length: 275mm
- Focal Ratio: F/4.5
- Image Circle: 44mm
- Tube Rings: Radian Modular Hex Rings
- Weight: 4 lbs
- Carrying Case: Radian Padded Insert Backpack
- Corrector: Integrated Corrector with three-element design
- Dew Shield: Included
- Dust Caps: Front and rear caps included
- Filter Attachment: 2″ / M48 Filter Vault
- Focuser Knobs: 10:1 Dual Speed with Locking Knob
- Focuser Design: Non-Helical Rack & Pinion
- Included Dovetails: 6.5″ universal Losmandy D Style and 4″ Vixen V Style
- Optical Design: Apochromatic Triplet Refractor
- OTA Length: (Dew Shield Retracted) 235mm
- OTA Outer Diameter w/o Hex Rings: 80mm
- OTA Outer Diameter: 90mm with Dew Shield
- Rear Camera Connection: M48 x 0.75 (wide T Ring compatible)
- Recommended Back Focus: 55mm (can be reached with included adapters)
- Rotator: 360º with Locking Knob
The Raptor 61 has a lot going for it, and I am not just saying that because I hold a sense of pride and ownership of this product. I believe that the added features and attention to detail have earned the reputation of “best portable astrophotography telescope”, but that’s not for me to decide.
I have taken my personal best images of the California Nebula, Heart and Soul Nebula, and IC 1396 using the Radian Raptor 61. This is a subjective decision, but I can tell you that the optical system did not hold me back from creating my best work in any way.
An included Bahtinov mask would have been a nice touch to this package, and a number of people have expressed this. For now, you’ll have to use your own focus mask, or simply fine-tune the focus on a bright star.
The Radian Raptor 61 was not meant to be used for visual astronomy, nor is it suitable for small galaxies or planet photography. If these are your aspirations, a much larger telescope with more magnification is a better fit.
But if you’re like me and prefer to capture large nebulae regions in the sky in a single shot, the Raptor should be a serious contender for your next wide-field astrophotography telescope.
Most importantly, I believe the Radian Raptor 61 package removes many of the early headaches amateur astrophotographers face when getting started.
Backspacing issues, mounting hardware, and focusers that aren’t up to the demanding challenges of deep-sky astrophotography are just a few of these hurdles that don’t exist with this telescope.
A positive experience from the beginning will help ease the astrophotography learning curve. The Raptor 61 is probably the easiest astrophotography telescope I’ve ever used in terms of finding focus, and framing targets.
It’s lightweight, and easy to balance, meaning you’re much less likely to run into any issues in tracking, even on an entry-level equatorial mount or portable star tracker.
The bottom line is, when you just need everything to go right (like when you’ve booked a last-minute Airbnb under dark skies to photograph the Andromeda Galaxy), you need a telescope that won’t let you down. That is the Raptor 61’s specialty.
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