In a market of solar telescopes, high-end filters and Herschel wedges, it’s fairly unusual to see budget equipment. However, Acuter has come up trumps with its Solarus 80 refractor.
This solar telescope comes complete with built-in white-light filter, solar finder, diagonal, zoom eyepiece, smartphone adaptor and a filter wheel pre-loaded with colour filters.
- Our guide to the best solar telescopes
While the telescope bundle is available to purchase on its own, Acuter also offers a complete telescope and mount outfit, including GPS solar tracking mount and tripod, which is what we’re reviewing here.
Receiving the full Solarus 80 refractor kit, we were keen to take advantage of some late summer sun.
Unboxing
Assembling the Solarus 80 setup was easy; we attached the pier extension to the locking bolt on top of the tripod, followed by the mounting head, before adding the mount and telescope.
We noted two options to power the mount: there’s an input port for an external power supply or you can use eight AA batteries.
Neither option comes supplied with the kit, so we opted to use batteries.
In less than 15 minutes, we were ready to look for sunspots. Heading outside, we found the full setup easy to carry.
Ensuring we placed it on even, flat ground was also simple, thanks to bubble levels on the tripod and mount.
Powering up, we waited for the mount to complete its initial search for the Sun before using the solar guider provided.
It took a couple of attempts, but we soon located it in our eyepiece with a slight adjustment of the mount’s slewing button – you need to press this button and the power button simultaneously to slew.
Glimpsing the Sun, we got that familiar wow factor, particularly due to the numerous sunspots present as it nears solar maximum.
While we struggled to see surface granularity, we were still impressed as we moved through the different coloured filters. Personally, we preferred the lighter options.
Changing filters required a bit of force, but we found holding onto the diagonal helped.
How the Solarus 80 refractor performed
Visually, we didn’t note any internal glare, enjoying clear views of the Sun’s surface.
The built-in zoom eyepiece offers three set focal lengths and magnifications: 5mm (80x), 10mm (40x) or 16mm (25x).
During our time with the Solarus 80, we found this handy as we didn’t have to keep swapping eyepieces.
The downside is not being able to interchange accessories, which limits your options longer-term.
While the 16mm length presented the Sun at a relatively wide field of view, we found it to be clear, sharp and in focus, thanks to the Solarus 80’s Crayford focuser.
We thought the 10mm view was optimal for this setup, as the solar disc perfectly fitted the field of view while the sunspots remained clear, sharp and perfectly focused.
At 5mm, the sunspots lacked the same clarity.
Of course, we couldn’t resist using the smartphone adaptor provided for a few snaps.
We discovered that if the phone had more than one lens, it was a struggle to find and focus the Sun in the right one, but once we did and clamped the phone in place, we were able to take some satisfying images, albeit noting some internal reflections.
Solarus 80 refractor in use
We thoroughly enjoyed our time with the Acuter Solarus 80 solar telescope and mount outfit.
It is well suited to beginner and intermediate astronomers looking to enjoy daylight sessions, and Acuter has clearly considered the suite of accessories included.
We found the mount's solar auto-tracking and built-in GPS nice to use, easily navigating to our nearest star.
This isn’t a telescope for observing prominences or the Sun's delicate surface details, but for sunspots it performed brilliantly.
While it would be unfair to directly compare this to higher-end solar scopes, the price point and viewing experience prove this is an excellent starter set.
With or without the mount option, the Acuter Solarus 80 shouldn’t gather dust: it’s rewarding and convenient enough to return to time and time again.
All in one
The Solarus 80 telescope and mount package includes everything a beginner solar astronomer could want.
Thanks to the pre-installed white-light filter, the photosphere of the Sun can be safely observed almost straight from the box.
Sunspots, partial and total solar eclipses, and planetary transits can be enjoyed with this budget setup.
We particularly liked the mount’s built-in GPS.
A few minutes is all it took for the mount to establish our time and location, before calculating the Sun’s azimuth and altitude via Acuter’s patented solar-alignment technology and commencing its search.
Slewing was smooth and quiet. While the Sun wasn’t quite in the eyepiece, a slight adjustment was all that was needed to centre it in our field of view.
Using the mount across several sessions, we found the location accuracy was consistently impressive for such a budget setup.
Tracking was also effective; we left the setup for over 30 minutes and returned to discover the Sun was still central in the eyepiece.
Solarus 80 refractor 5 best features
Built-in zoom eyepiece
Zoom eyepieces are relatively unusual in beginner kits, but the Solarus 80 is fitted with a 5–16mm version. This allowed us to view the Sun across three different focal lengths and magnifications, providing options to adapt our field of view to suit the conditions of the day and individual eyesight.
Diagonal
The 90°-angled diagonal comes fitted to the Acuter Solarus 80, sandwiched between the built-in filter wheel and eyepiece, and provided a comfortable viewing experience. The internal mirror provided an upright, back-to-front image. Note that the diagonal is not rotatable.
Filter wheel and filters
The filter wheel comes preloaded with red, yellow, blue, green, orange and neutral-density filters to help boost sunspot contrasts and details according to user preference. An empty slot is also included, should you wish to do solar observing with only the built-in white-light filter. A simple switch allows easy movement between the options.
Universal smartphone holder
Acuter has considered the needs of budding solar photographers with this universal holder. When correctly positioned across the eyepiece, it allowed a steady shot of the Sun to be safely taken. We were pleased to note that the holder had a secure grip of our phone throughout each photography session.
Vital stats
- Price: £549
- Optics: Multi-coated, built-in glass white-light solar filter
- Aperture: 80mm
- Focal length: 400mm, f/5
- Mount: Go-To solar tracking, 16x and 1,200x slewing speeds, 0.625 arcsecond resolution
- Extras: Solar finder, filter wheel, filters, 90º diagonal, accessory tray, Vixen-style dovetail, smartphone holder
- Weight: 1.75kg; 4.05kg with mount and tripod
- Supplier: Optical Vision Ltd
- Email: info@opticalvision.co.uk
- www.opticalvision.co.uk
This review appeared in the November 2024 issue of BBC Sky at Night Magazine
