Getting in and out is a by and large a breeze (more on that in Grant’s verdict below) thanks to the long and wide zip opening that can folded back. There’s also a layer of bug mesh so on dry nights you can get full ventilation while you lie back and watch the stars.

Then there’s the sombrero aspect. That’s right – this bivy doubles as a hat. When it’s raining or snowing, this feature of the Interstellar is actually very useful. It’s designed so that when you sit up while in the bag, balance the top end of it on your head and use it as a canopy while you’re sorting your backpack, cooking or just enjoying a view. You can also open up slits in the zips on either to allow you to stick your arms out. So in essence, this is a bivy bag that you wear…kind of. Grant Hyatt has been testing the Interstellar since our initial Outdoor100 Brecon Beacons testing trip. Here’s how he’s got on with it…

Tester’s Verdict

Grant Hyatt, Outdoor photographer

“With one pole and different colours for the base and top of the Interstellar Bivy, it’s clear and easy to work out how to set this up. The pole sleeve is stitched and sealed off at one end and secured with a healthy dose of velcro on the other, this feels secure and hasn’t slipped or come away in the three nights I’ve had in it so far. There’s a loop at either end of the bag, which could be used to peg it out in windy conditions, I’ve not used them yet, but looking at them, I feel confident that they’re secure enough to stop me having to chase it down the mountainside!

“I’ve found the Interstellar has ample space inside for my pillow, sleeping mat, four-season sleeping bag, as well as a couple of small precious items at the head like a phone/camera or small dry bag. The hoop of the sombrero allows a little head room, which I’ve found is enough to be able to prop myself on one elbow to check my phone or plan a route for the next day.

“The base feels thick enough to cope with damper conditions without wet spots at the pressure points, and the top stretchy fabric feels surprisingly durable also. It’s completely waterproof and windproof, as you’d expect. I don’t doubt what Outdoor Research say about this being a four-season bivy. The only issue I had with breathability was on the first night where the temperature was below freezing and some condensation that had formed between my sleeping bag and the bivy began to freeze.

“That didn’t put me off, far – from it actually, it gave me a little more confidence in the bivy and the perks that being out in one can have. The other nights I’ve used it have been cool and clear, and I’ve had no condensation build up.

“There are a lot of zips – in fact, a total of 12 altogether. Fortunately, they’re all neatly labelled and they glow in the dark, but if, say, you had the bug mesh and outer zipped over your face, you could potentially have between two and four zips to undo in order to get out, depending how you secured them going to bed – so a bit of zip discipline is involved here! The design is very really useful, but it’s worth getting to know the zip process beforehand.

“I’d definitely recommend this bivy to others. If the skies are clear, nodding off while counting the stars has been incredible, made all that more special by an occasional meteor sighting. It’s been a pleasure to use, and really adds to my experiences when out photographing the Brecon Beacons.”

Trade Secrets

Liz Wilson, Head of Product at Outdoor Research

“The inspiration for the development of the Interstellar Bivy was sparked by a summit attempt on Washington State’s remote Glacier Peak (3,207m). Outdoor Research Design Innovation Manager Nathan Jenkin and team were discussing summit route options during a period of high avalanche conditions and a mixture of rain, snow, and hail. Team members were using older-style bivies on the climb and as they reviewed optional lines of ascent, sorted gear, studied maps and prepared meals they wished they could sit up and remain protected from the elements while having their arms and hands-free. Nathan says that following this, they dreamed up the Interstellar Bivy as a combination of a bivy, a jacket and our Seattle Sombrero rain hat, a revolution, and evolution of a traditional bivy.”