Hands-on review: Unistellar eVscope 2
Image credit: Unistellar
Smart software and portability make up for what this telescope lacks in image detail and help it hit an astronomical sweet spot.
This smart telescope aims to hit the ‘Goldilocks’ spot. You can get larger models with larger optics, that deliver more detail, but they’re too bulky to carry with you. You can get smaller models that are highly portable, but the image quality suffers as a consequence. Unistellar hopes that the eVscope 2 is just about right. You can use it in the garden but also grab and go, using it anywhere.
The telescope is portable and comes with a large rucksack. A tall ‘going on my Duke of Edinburgh Award hike’ sized rucksack, designed with cushioning to fit the telescope well and space on the outside to strap on the supplied full-size tripod. It’s a neat setup with a premium feel - and portable enough that you absolutely could hike to the top of a mountain to stargaze.
Telescope-wise, it’s a 4.5-inch reflector with a focal ratio f/3.9. The latter is focal length divided by aperture, an indication of the telescope’s light-gathering ability and therefore speed (how long it needs to stare at a celestial object for to take a good picture).
Specs have been chosen for photographing wider field of view celestial objects such as nebulae – the showstoppers of the astrophotography world. It boasts a Nikon electronic eyepiece with best-in-class microOLED screen and sophisticated optics. Its built-in 7.7 megapixel sensor automatically stacks images for astrophotography.
It’s paired via direct WiFi with the Unistellar smartphone app. What’s more, it gets software updates as the tech improves. So it benefits from Unistellar’s brand new Deep Dark Technology which improves the image. Its proprietary algorithms mitigate the impact of light pollution, for better contrast (read: see more stars) and colours in cities.
Automatic setup is fast in theory. Physically, we found it easy to set up the sturdy-yet-light tripod and make small adjustments to the legs to get it level (there’s a spirit level bubble on the top, so you can tell). The eVscope 2 pops on top and you tighten two screws by hand to secure it. Then just power it on - it’s USB rechargeable, so you really can take it anywhere - and remove the dust caps from the lens and eyepiece.
In theory, the telescope then automatically calibrates itself. Via GPS it knows its location and time, so it knows what the night sky should look like. You point it up at the stars and it recognises celestial objects (matching them with a coordinate database of tens of millions of stars) and finds its own bearings. After which, you can simply use the app to pick an object and the motorised telescope will take you to it.
In practice, the first time we set it up was a struggle. A clear night but typical city light pollution. The scope powered up and could see stars but it couldn’t manage the orientation. Time and time again, it would look at some stars, move a bit and look at some more, move a third and final time to look at more, then quit and say it had failed. The stars were blobby with a cross in the middle and hard to make out, but we couldn’t find any controls we were missing and the app didn’t direct us. It's a shame that the app didn’t tell us we were missing a simple trick. After struggling several times in a row, a pop-up saying “do your stars look like this?” would have been great.
It turns out that it was out of focus and there’s a big knob at the base of the telescope tube for this. In fact, it’s best to use that twice. First, to get stars on screen looking like, well, stars. Then complete the orientation process. Finally, use the app to select a bright star and adjust focus more precisely by adding the Bahtinov mask (it’s tucked inside the lens cap) and fine-tune the focus until you get three lines over the star, neat and centred.
Second time lucky and the telescope worked great. Thanks to focusing, the stars looked good. What’s more, countless other stars were suddenly visible.
In the app you can set limits on the visible sky (how low to go to the horizon, which directions not to bother with because there’s a tree in the way). And then the app tells you which visible celestial bodies are brightest and best. Tap the app and the telescope goes straight to it. You can then press a photo button to begin stacking images, to combine them for astrophotography that shows much more than you can see with the naked eye.
Stars were good and bright but showstoppers like galaxies and nebulae were undermined by the city light pollution. After attempts at many, we only succeeded at good photos of the Ring Nebula. Still, the telescope brought out so many stars that it was hard to fault. Performance was good enough that it just made us crave darker skies.
Automated image processing cancels a lot of light pollution and interpolates, but you can still see noise in the image. Unistellar’s image processing has been refined over time thanks to shared user data. It’s optional to share your own data but it can help improve future products. There’s also a community aspect and a scientific one: this is the first time scientists have had access to thousands of telescopes all over the world. Citizen scientists using Unistellar telescopes recently shared their data with NASA, contributing to a paper in Nature about the colour of the plume from the DART mission, with unique findings and observation angles all over the planet, confirming repeated results.
Another example of its serious use is observations of a very long exo-planet transit, in a solar system of special interest because it’s similar to ours. Unistellar owners, between them, observed it for more than 30 hours, thanks to the global network of telescopes.
Coming soon is a new smart solar filter, with new software that works by day to analyse the brightness of the sky and then finds the Sun for you. Yes, it’s not hard to find the Sun yourself, but it can be dangerous – once again, the Unistellar can do the heavy lifting.
For the same money, you can get better telescopes that are larger and not so portable. Size matters, but clever software does a good job of making up for what the eVscope 2 lacks in image detail, making it a good-if-pricey buy that hits the Goldilocks sweet spot.
DwarfLab Dwarf II
Even smaller than the Unistellar, at 130x204x62mm this is the size of a hardback novel. So it’s more portable but images are less detailed. A mini tripod and auto star tracking and stacking offer take-anywhere astrophotography.
Celestron Starsense Explorer 10-inch Dobsonian
This uses the power of your smartphone to analyse the night sky and find its bearings. Then the app generates a list of visible celestial objects. You move the telescope by hand but on-screen arrows direct you. Its large aperture means more light, more detail. You can add astrophotography.
This quirky-looking 80mm aperture refractor telescope simplifies stargazing. It sits on a mini tripod, is set up in minutes and controlled via app. Again it’s designed to track celestial objects and stack images to create stunning digital photos.
Sign up to the E&T News e-mail to get great stories like this delivered to your inbox every day.