Refractors are generally considered an ideal imaging telescope due to their sturdiness and reliability.
This makes them attractive for beginners and advanced astrophotographers alike.
The RVO Horizon 80 ED doublet joins Rother Valley Optics’s Horizon family of imaging refractors, which also includes the 60 ED, 72 ED and 102ED, each instantly recognisable by their distinct orange and turquoise tube rings and accents.
We were keen to see how this mid-weight sibling stacked up against other doublets on the market.
Read our pick of the best astrophotography telescopes
Unboxing and setting up
We received the full RVO Horizon 80 ED imaging package, which included an impressive array of imaging accessories within a smart aluminium carry case.
Nestled beside the OTA, which comes fitted with tube rings, mounting points and a dovetail, were the guidescope, an illuminated eyepiece and a 1.0x field flattener.
You can instead choose a 0.8x flattener when ordering from the RVO website.
Overall, the kit provided an excellent first impression, with all components beautifully machined with a smart, brushed-metal finish.
How the RVO Horizon 80 ED performed
Winter skies were typically temperamental, but we soon had an opportunity to use the 80 ED for a visual session, popping the eyepiece into the finderscope and attaching to the OTA.
We should note that the top Vixen bar arrived upside down, so an Allen key was needed to flip this around.
We particularly liked the adjustable Vixen clamp attached to the finderscope, which makes it easy to fit a range of different mounting points.
The illuminated eyepiece allowed us to swiftly locate and centre targets.
First slewing to a 60%-lit waxing Moon, we were pleased with the 80 ED’s colour correction, observing very little fringing, even when pushed to higher magnifications.
Using our 9mm eyepiece at 62x magnification, we enjoyed some beautifully crisp crater details.
Moving across to the Pleiades, we were treated to a clear and sharp view.
Astrophotography
Before the clouds rolled in, we attached our DSLR and fired a couple of test shots, minus the flattener.
While there was a small amount of curvature towards the edges of the field, this was by no means prohibitive or beyond some post-processing tricks.
Later, we set the 80 ED up for our next imaging window.
Both flatteners require 55mm between them and the camera sensor, and while this is the industry standard, we’d always recommend separately purchasing a good selection of shims and spacers to ensure this can be reached for your camera.
For our monochrome CCD and filter wheel, we were easily set up with the help of a spacer.
We should highlight that both flatteners proved very tight to screw on, leaving us in no doubt that they were secure once fitted.
Prepared to cloud-dodge, we set our sights on two popular winter targets: the Heart Nebula and the California Nebula.
We were particularly impressed with the 80 ED’s focuser, which provided just the right amount of tension as we perfected our stars using the fine focus.
While the focus lock was a little difficult to reach with gloved hands in the dark, the rest of the adjustment knobs were large and easy to grip, making fine-tuning this refractor a breeze.
Stacking and processing each image showed that the flattener had achieved a flat field of view and crisp targets that were easy to finesse in Photoshop.
RVO Horizon 80 ED for beginners?
Considering the price point, the full imaging package is an ideal prospect for imagers already familiar with astrophotography, who know that they’ll use it.
That is not to say, however, that the 80 ED isn’t appropriate for beginners; it certainly is simple to operate.
The accessories provided in the Horizon imaging package give relative newcomers an important advantage: the capacity to progress and adapt as target lists develop or users seek to maximise their data-capture capabilities.
We felt that this was an ideal bundle for astrophotographers looking to graduate from widefield to deep-sky imaging or support the transition from manually operating a Go-To mount to a guided or laptop-driven setup.
For us, it certainly rose to the challenge.
The Horizon 80 ED is a sturdy imaging workhorse that will hold its own for many years of deep-sky capture.
A great travel astro-imaging telescope
At 80mm of aperture, the RVO Horizon 80 ED doublet is placed comfortably between widefield and heavy-duty refractors.
It boasts a focal length that’s perfect for Messier Catalogue and NGC objects, including nebulae, star clusters, or galaxies such as the Andromeda Galaxy, M31.
For astrophotographers who are hungry for more imaging opportunities, it also provides an excellent field of view for capturing the disc of the Moon.
But a refractor is only as good as its optics.
The FPL-53 glass of the Horizon 80 ED’s objective lens reduces aberrations to optimise image quality.
As a doublet, the two-lens system is also designed to limit light distortions for a clean image, without the weight of extra glass.
The standard 30cm Vixen-style dovetail bar provides plenty of scope to balance this OTA once kitted out with a full suite of accessories.
This makes it an ideal grab-and-go astrophotography option for a variety of different mounts and configurations.
Best features
Illuminated crosshair eyepiece
The 24mm eyepiece is a handy tool for many astrophotography processes, including fine-tuning our Go-To mounts through three-star alignment. Slotting easily into the back of either the guidescope or OTA, the red crosshairs also allowed us to optimise long-exposure images via more accurate drift alignment or centring on guide stars.
50mm guidescope with helical focuser
Guiding is considered a must for maximum exposure times. This 50mm Horizon guidescope is perfect for imagers looking to make this leap. It also doubles up as an excellent finderscope to help with manual star alignment. Meanwhile, the helical focuser ensures no focus creep once a guide camera is attached.
Top mounting points
A top Vixen bar and finderscope mount are supplied, allowing for the addition of a guidescope, guide camera or even a second imaging telescope if desired. The ability to easily adapt or upgrade is a much-desired capability of any setup. As accessories change, mounting options can prove expensive, but the Horizon 80 ED solves many tinkering challenges.
1.0x field flattener
A flat field is an astrophotography essential but often can’t be delivered by beginner setups. However, the flattener included in the Horizon imaging bundle allowed us to correct field curvature. Designed for the Horizon 80 ED, the 1.0x flattener preserves its 560mm focal length for pin-sharp stars. An optional 0.8x reducer/flattener is also available.
Rack and pinion focuser
Furnished with a 10:1 microfocus, this dual-speed focuser speeds up achieving sharp stars. A lock secures focus once reached, while the indexed drawtube further simplifies a session by allowing you to note the focus position. The 2-inch barrel is ideal for most imaging setups, although a 1.25-inch adaptor is included.
Vital stats
- Price: £1,015 with 1.0x flattener; £1,025 with 0.8x flattener
- Optics: FPL-53 doublet
- Aperture: 80mm
- Focal length: 560mm, f/7
- Focuser: Dual-speed rack and pinion
- Extras: Tube rings, Vixen bar, dovetail, guidescope, 1.0x field flattener, illuminated eyepiece
- Weight: 3.45kg (OTA), 4.75kg (full package)
- Supplier: Rother Valley Optics
- Tel: 01909 774521
- www.rothervalleyoptics.co.uk
This review appeared in the March 2024 issue of BBC Sky at Night Magazine
