Astrophotography is famously hard on the wallet and demanding of your free time. Sure, it’s easy enough to snap a photo of the moon on your phone, but getting a good shot of a galaxy is an entirely different. But all that’s changing, thanks to a new wave of smart telescopes that are ushering in a revolution in deep-sky photography.
The ZWO Seestar S50 is one of a cluster of these automated marvels that have arrived in the past few years. Like the others, it combines a tracking mount (to keep the target centred) with a computerized database and a camera in one compact package.
What’s more, it only costs $550 / £500 – a fraction of what you’d spend on a ‘proper’ deep-sky setup and a fair bit less than rivals such as the Unistellar Odyssey Pro and Vaonis Vespera Pro.
All sounds too good to be true, right? Except it’s not – and I know because I’ve been using one for the past year.
Deep skies are the limit
To explain why I’ve fallen in love with the Seestar S50, I need to explain why I’d fallen out of love with astrophotography in the previous few years.
I’ve always been fascinated by space. On my first day at school, I was asked to draw a picture showing what I wanted to be when I was older. “I’m going to be a spaceman!” I excitedly told my parents later, but sadly, a lack of coordination and a fear of heights put paid to that idea. Even so, my fascination with the skies never waned, so taking photos of deep space seemed like the next best thing.
A little research soon taught me that I needed more than just a camera – specifically, a mount. Yes, you can do astrophotography with one of the best mirrorless cameras, but without a mount to track the sky, you’ll get star trails as the heavens revolve (or rather, as the Earth does). These look very pretty, but they’re not what I wanted.
No, I wanted to take photos of galaxies such as Andromeda and fantastically named nebulae such as the Horsehead and Flaming Star. So, I bought an equatorial mount, a refractor telescope, and about a dozen different adapters and cables to connect my Fujifilm camera to them.
It took me several nights to understand the arcane software. I needed to control it all and work out how to do polar alignment, which involves lining up the mount with a star so it tracks accurately. But once I’d mastered that, I was up and running.
Over the next couple of years, I took some wonderful images that I’m really proud of; the one of the Orion nebula above is my favorite. None of them rivalled those produced by the pros, but they scratched an itch.
The trouble is that astrophotography is really hard.
It’s hard on the wallet because telescopes aren’t cheap, and you also need to buy an (even more expensive) tracking mount, filters, a dedicated astro camera, and about a hundred different adapters and accessories.
It’s hard to get great photos because most of these objects are really far away, and every photon counts. You mess things up even a little, and you could end up with a blurry mess for your night’s work.
It’s hard on the back because mounts and telescopes are seriously big and heavy. If you have to store them out of the way, as I did, it’s no fun to lug them all the way to the bottom of the garden.
And it’s hard to find the time because setting up involves complicated things like polar alignment, a dizzying array of software interfaces, and about a thousand cables. Then, by the time you’re done, it’s cloudy, it’s 2 a.m., and YOU HAVE LITERALLY ACHIEVED NOTHING TONIGHT.
All of which is a very long-winded way of explaining why the ZWO Seestar S50 has changed my (astrophotographic) life.
A Seestar is born
By the end of 2023, I’d given up on astrophotography because it was too much trouble, but then I read about the ZWO Seestar S50 and decided to give it another try.
Here was a smart telescope that would make it easy for me to take photos of the sky. It promised to combine the camera, telescope, and mount in one package and let me control it all from the comfort of my lounge via an iPad. It has a 250mm focal length and 50mm aperture and takes full HD photos via a Sony IMX462 sensor. All pretty decent.
The 64GB of storage and 6,000mAh are bonuses, too. The whole thing is small enough to pack into a travel case and weighs only 2.5kg. Plus, I was already well aware of ZWO, a Chinese company that has long made some of the best dedicated astrophotography cameras. Best of all, it was reasonably affordable, at $550 / £500.
Critics online worried that it wouldn’t take great photos, given the price and relatively modest specs of the camera, mount, and lens.
For starters, it was an alt-azimuth mount – the simplest type, which would only let me take photos of 10 seconds or so before star trailing was apparent. My equatorial mount, in comparison, could shoot for minutes at a time, capturing many more photons each time for better image quality.
However, I’m a big fan of that old adage that the best camera is the one you have with you. I’d rather take average photos every three nights than great photos once every three years.
Inevitably, the UK was shrouded by clouds for the first few nights after it was delivered, but eventually I got my chance to try it out – and wow!
Set up was a cinch; the software is incredibly intuitive, and hardware-wise I simply needed to screw the supplied tripod into the telescope unit. Within about 10 minutes, it was set up and snapping away.
The Seestar S50 works by taking multiple photos of your target and’ stacking’ them together to reveal the details.
I could go into extensive detail about how this works, but all you really need to know is that by combining dozens (or even hundreds, or thousands) of individual images, you can reduce the noise and increase the signal-to-noise ratio.
This is vital because deep space objects are a long, long way away and often incredibly faint. A single photo usually shows little more than a vague smudge, particularly if, like me, you live in a heavily light-polluted area.
By stacking many photos, you reduce all of the noise and bring out the details. The GIF above shows the process in action on my Seestar S50, albeit sped up; to get that kind of detail in reality would take about 20-30 minutes, depending on how dark your skies are.
The Seestar S50 does all of this for you; you can literally watch the object appear in front of you, without needing to touch a thing after choosing your target. It’s like magic.
Choosing the target is easy, too, because the Seestar app has a full Sky Atlas built in. This contains thousands of suitable targets arranged into categories; you can simply click on the one you want to image and let it do the rest.
Of course, you can make things more complicated if you want to. For starters, ZWO has added multiple new features via firmware updates.
Among these are the ability to take mosaic photos – so you can image much larger objects, such as the Rosette nebula or Andromeda galaxy – and a planning option to enable you to set up a sequence of targets throughout the night, so you can go to bed and let it do its thing.
The best – and most complicated – is the relatively recent addition of an EQ mode. This lets the Seestar S50 act as if it were an equatorially mounted telescope and, therefore, take longer exposures.
This requires a little more set-up time, as you now need to polar align – something I thought I’d left in the past. However, the software walks you through the process, and I still found it a lot easier than I had with my old rig. You will also need to invest in an equatorial wedge or pan-head tripod to use it.
The results are worth it, though. One drawback of the Seestar S50 compared to more expensive set-ups is that it can take a long time to get a decent number of frames.
In alt-azimuth mode, the tracking is nowhere near as accurate as that of an EQ telescope. This means that about one in every three frames has star trailing and is automatically discarded by the stacking software. This adds a lot of time to the process of getting a good photo.
In EQ mode, however, it tracks far more accurately, meaning you can capture more data – or more targets – in a night. Anyone who lives under cloud-infested skies will appreciate that advantage.
Heavenly bodies
None of that would matter if the results were not good enough to want to share with people, though. Fortunately, they are – but there is a caveat here.
Astrophotography is only half about the actual photography part, with the other bit being the image processing.
The Seestar S50 serves up pretty good out-of-camera images, doing the stacking for you and giving you recognizable results. But they are noisy, particularly if you don’t have dark skies. Nor is this surprising; pro and semi-pro astrophotographers use cooled cameras with large sensors, and the Seestar S50 has neither of those.
The solution is to process the images after they’ve been taken, ideally using specialist astro-processing software. I use a program called Pixinsight, which is an absolute must for anyone who wants the best results, albeit expensive.
Free alternatives are available, though, and you can also improve images using Photoshop and Lightroom. Anything that can remove noise and fiddle with levels will have a positive effect.
The image below of the IC 434 region and majestic Horsehead nebula shows the difference before and after processing. Pretty cool, right?
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Honestly, I spend almost as much time processing images as I do taking them. But I still have so much to learn; this is a hobby that could easily eat up all of your free time if you allow it to.
Still, I’m pleased with what I’ve achieved. The photo of the Rosette nebula below is now my favorite image I’ve taken, although I know I can improve it if I add more data and re-process it. It will never be as good as I want it to be.
I’m also pleased with my version of the Cone nebula. The Seestar S50 has three built-in filters – one UV/IR Cut filter, one dark filter, a dual-band anti-light pollution filter. You can turn the latter on or off depending on the target, and with nebula such as the Cone the dual-band filter really helps to bring out the swirling clouds of dust and gas.
The S50 also does pretty well with star clusters such as M67, but unfortunately my processing skills are not yet up to the job of doing them justice. Either that or my focus is not quite right, but they always appear softer than I’d like them to be.
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Likewise, the image of the Whirlpool galaxy, M51, is a bit soft. With more data, I’m pretty sure I could bring out more detail in the dust lanes swirling around the galactic center on a clear night or two. I’m not happy with the stars, either; I’m never happy with my stars.
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The Seestar S50 is not the telescope to buy if you want to take photos of the planets – the focal length, aperture and sensor are not suited to it. But you can try, and I’m still ridiculously proud of my Jupiter considering it’s little more than a yellow-y smudge.
But look, you can see Jupiter’s bands! I took that! From my garden just outside of London! That will never not be exciting.
It does much better with the moon (which is easy) and the sun. For the latter, you use the supplied solar filter. I managed to get a lovely timelapse of the recent solar eclipse using it, and even on a standard day, it’s fascinating to look at sunspots and how they change.
I’m well aware that my photos are not the best, not even close to it. I need to get much better at processing and move away from all of this light pollution. I’ll almost certainly upgrade from the Seestar S50 when I have more time and money.
ZWO has already released a sequel, the even smaller and cheaper S30, and recently announced the S30 Pro – which takes that model’s wider field of view and adds a much better (and newer) sensor. I’m quite tempted by that, but will probably wait for the rumored S50 Pro.
But whatever I buy, the Seestar S50 has taught me one thing: smart telescopes are here to stay. Anything that brings the wonders of the skies to more people is to be applauded, and the S50 is a true game changer in that regard. I can’t praise it highly enough.