RVO Horizon 60ED Doublet imaging refractor
A highly portable telescope that works well for imaging and visual observing
The new Horizon 60ED imaging refractor from Rother Valley Optics is a lightweight, portable telescope designed for grab and go astronomy. The full imaging package we received for review includes a guidescope and a field flattener for astrophotography; although the telescope is also available on its own without accessories for a price of £499. The portability of the Horizon imaging package is particularly impressive; supplied in a sturdy case that contains the whole assembly, the only extras required for an astrophotography trip would be a DSLR camera and a suitable mount. The complete setup, including a DSLR, weighs less than 3kg, so it could be easily accommodated by most star-tracking mounts.
Setting up the Horizon 60ED imaging refractor for an imaging session is quick and simple, and first-time users will appreciate the easy to follow, three-step pictorial guide, which explains how to remove the visual back from the telescope and replace it with the field flattener. A standard 48mm T-ring screws on to the back of the field flattener, and the DSLR camera attaches onto that, which gives optimal spacing for a flat image field with no additional spacers or measuring required. The telescope features a 60mm objective lens, and a focal length of just 360mm, which offers a wide-field image scale at a respectable f/6 focal ratio. Our full-frame DSLR camera was able to capture the three stars in Orion’s Belt right down to his Sword, including the impressive Orion Nebula, M42. At this image scale, guiding the telescope over typically short DSLR exposures might not strictly be necessary on a mount with good polar alignment, but the supplied 32mm guidescope is a useful standby, which can be adjusted easily to match the imaging area, or perhaps to track on a comet while taking photos. Guide cameras with 1.25-inch nosepieces slide into the guidescope and can be adjusted back and forth to achieve focus. Alternatively, an M42 x 0.75mm male thread on the guidescope’s rear allows you to attach other cameras.
Ready for action
With everything set up and ready to go in just a few minutes, we turned our attention to capturing some images. Focusing our DSLR was very straightforward too with the dual-speed option, and although the
focus lock knob was a little awkward to access with cold fingers, once locked the focus held well in stable temperatures.
With the comparatively wide view available to the camera, we wanted to frame each shot for best effect, and this was easily accomplished with the built-in rotator. This sits in front of the field flattener, a single thumbscrew allowing the camera to rotate 360°. Once set, we started taking images within the constellation of Orion, the Hunter to assess the performance of the field flattener. This proved to be remarkably good, especially given our full-frame camera, with just a little distortion to star shapes in the corners of the image; indeed, the reassurance that the camera and scope were nicely matched allowed us to get on with astrophotography, no fiddling about required
– exactly what we look for in a portable setup.
Removing the flattener and reattaching the visual back allowed us to use our 2-inch diagonal and eyepieces for a visual observing session, as a bright Moon dominated the sky. Our 13mm, 100° apparentfield-of-view eyepiece offered us around 28x magnification; ideal for exploring large clusters like the Pleiades, M45, where we noted a nice contrast
and good star shapes across most of the view. Despite the bright Moon we were able to pick out a good amount of nebulosity around the Orion Nebula, M42, and moving down through 10mm and 5mm eyepieces the Trapezium area was clear and sharp. Although primarily aimed at the astrophotography community, we found the Horizon 60ED offered pleasing, encompassing views, allowing the viewing of familiar targets in their wider context.
Overall, we were pleased to discover that the Horizon 60ED refractor is a well-priced, very capable astrophotography telescope – in an extremely portable package – with the added bonus of pleasant visual observing as an option.