ZWO’s Seestar S50 smart telescope is an all-in-one portable astrophotography set-up with beginners in mind, designed to make imaging as simple as possible. Sounds great, but what’s it like from a city? Let’s find out…
First impressions
I was excited to hear about ZWO’s plans to release a smart-telescope. There are a few available already from other manufacturers, like the Vespera and DWARF II, but ZWO are big players in the astrophotography world. I like their kit and use some, including an ASIAIR Plus and 2600MC Pro camera. They’ve got a lot of experience with making equipment affordable and user-friendly, so the signs were positive from the start. Then the price was announced: £539 (from FLO). If you’re new to astro then this might seem expensive, and while it’s certainly not cheap, it represents remarkably good value for the hardware. I’m not the only one to think so, as these Seestar units have been flying off the shelves, leading to long delays. Lucky I got in there early and was a day #1 pre-order direct from ZWO!
Hands-on with the Seestar S50
The Seestar is well packaged in a kind of tough polystyrene case. It’s lightweight and fairly sturdy. The case has a little carry handle and clips to keep it closed, but no lock.
Open the case up and it comes with nearly everything you need:
- The Seestar S50 itself;
- Small tripod;
- USB C charging cable;
- Instruction manual;
- Solar filter.
It’s well designed and everything looks great. It feels like next-generation tech. I was impressed that ZWO had squeezed a tripod into the case, and the inclusion of a solar filter was welcome.
The telescope is made from a hard plastic, which keeps the weight (and cost) down, but is prone to scuffing. These telescopes won’t look pristine for long. However, it’s the lens that needs to be kept in good condition, and the telescope tucks that out of harm’s way when not in use so no lens cap is needed. It’s a neat solution.
It’s all very well thought-out. There’s an in-built dew heater, and even a basic dualband filter to help with imaging narrowband targets. An internal battery is rated for six hours, and in my experience that’s about right, although this will vary based on your conditions — very cold temperatures and use of the dew heater will drain the battery faster. You can recharge it, or even directly power it, from a simple USB power bank. ZWO state that the Seestar will work if the temperature is between -10 and +40 degrees C, and charging can take place between 0 and +40 degrees C.
I said that nearly everything needed is included. To complete the package you’ll need a smart device to run the software and display the images. To clarify for any complete beginners, the Seestar isn’t a conventional telescope with an eyepiece that you look through; it’s entirely digital, so you need a smartphone or tablet to control it and view images.I tried running the Seestar app on a Windows laptop using the Android emulator BlueStacks, but couldn’t get it to work due to Bluetooth issues. Someone tech savvy in this regard may have more luck.
It’s fairly easy to set the telescope up. The Seestar screws on top of the tripod, you extend the legs if you want, and then power it up. Actually, that last step did initially throw me. I pressed the power button and the lights came on… but then nothing. After some experimentation I realised that pressing the power button activates the battery indicator lights; to turn the unit on you need to hold the power button down for a few seconds.
Connecting to the Seestar was quick and easy, using its own WiFi connection. You can also use Station Mode, where the Seestar connects to your home network, thereby extending its range and allowing you to use the internet and Seestar at the same time.
Then an issue: a message flashed up saying that the Seestar wasn’t level. Two circles were displayed, and it’s like a mini-game to adjust the tripod’s position and leg length to get the circles to overlap, thereby indicating that it’s level. The tripod is the weak link, as it’s rather small and fiddly to adjust in this way, but given the good value of the whole kit, as well as its portability credentials, it would feel churlish to criticise too harshly.
The user interface is good on the whole, although not intuitive enough that a user — especially a beginner — would be able to work everything out right away. There are some quirks and it can be hard to find the option to do exactly what you want. For example, it took me a while to find how to turn the dew heater on. And would a beginner even know when they should be doing this? Also, upon entering the sky map (where you can scroll around and choose targets) it started with a view of the southern hemisphere. Oh, and even after using it extensively for several weeks, I’m still not sure of the best way to actually get images onto my main computer. Hook the Seestar up to it using a USB cable? Email saved images from my phone to myself? Finding pictures to transfer is harder than it should be.
I do have another gripe with the Seestar’s app. The images used throughout, such as in the object catalogue, are stock images taken with other telescopes, and as such are generally much better than you’ll realistically achieve with the Seestar. Check out this image of Jupiter, for example:
Maybe it’s not such a sin for a page explaining opposition, as in the example, but if you’re a beginner and aren’t sure what views you’ll actually get through the Seestar, showing images taken using high-end imaging rigs are misleading. I think it’s basically the same as cheap telescopes putting photos taken by the Hubble Space Telescope on their boxes. You’ll see what Jupiter actually looks like through a Seestar S50 later in this review.
First light
On the first clear night I eagerly selected a target. The Seestar sparked into life, slewed to the object, focussed, and began gathering data. This is without any alignment process, other than levelling the telescope. If you’re old-school then you’ll know how impressive this is. No three-star selection, fine tuning, polar alignment. The Seestar just does it all, using plate-solving (taking photos of the sky and cross-referencing with star charts saved in its internal memory) to point in the right direction. It’s very, very good, and works even through the light pollution of a city.
Talking of city lights, how does it fare at imaging deep sky objects? The Seestar takes 10-second exposures, and automatically stacks them to make a longer integration. It does this in real-time, meaning you can see the image get better before your very eyes.
Here’s a single 10-second exposure of The Double Cluster:
That’s not bad. But what if we keep collecting light?
This is two hours of data. The Seestar app automatically takes all the data, combines it, and displays an integrated image. We can see lots more stars, and better colour too. This is to be expected, as long integration times are essential for combatting light pollution. The Seestar’s algorithm decides whether a particular 10-second exposure is worthy of adding to the live stack. During my testing about 1/3 of the exposures were deemed to be poor quality and were discarded, so a two-hour integration may actually take you closer to three hours.
Here are some other example photos.
55 minutes on The Andromeda Galaxy. We can see the bright core really well, and some dusty lanes. You can boost the brightness in the app, but the image shown here is just using default settings. Remember, this is from a city centre, and I think it’s pretty good. With properly dark skies you’d get to this level of detail much faster, but I always recommend thinking of urban astrophotography as a marathon rather than a sprint.
This image does demonstrate a limit of the Seestar S50 though: you can’t rotate the telescope or sensor to adjust the framing. Ideally the sensor would have been 90-degrees to where it was, meaning the whole galaxy could fit the frame. Alas, I had to be content with chopping the edges off the galaxy, and having dead space at the top and bottom of the image.
What about something very faint?
Here’s 90-minutes on The Iris Nebula. We actually see some detail in the nebulosity, which is impressive. But it also demonstrates another constraint, which I think is the biggest limitation of this telescope for the city astrophotographer. Drumroll…
What’s the catch?
…drumroll continues… field rotation. Higher-end imaging systems tend to use equatorial mounts, which track objects in arcs (right ascension / declination) as they move across the sky. However, the Seestar uses a simpler altitude-azimuth (up down / left right) approach. This means that a target seems to twist in the sky over a night. This can be seen clearly in the image above: look at the top-left and bottom-right corners. That’s the result of field rotation. You might get away with it for small targets right in the centre, but something that fills your entire frame? Probably not.
Just how big an impact this will have depends on your target’s location in the sky and how long you’re imaging for. But the bottom line is that field rotation makes it very challenging to complete multi-night projects that are necessary for really high quality images from a city.
Does that mean the telescope is a bust for urban astrophotographers? No, but we need to be aware of its limits.
Narrowband
Many astro targets give out most of their light in narrowband wavelengths, and the Seestar S50 comes equipped with an internal dualband filter to help get the best images of these objects. These filters also handily block lots of light pollution, which is good news for city imagers. The particular dualband filter used in the Seestar has fairly wide bandpasses, so isn’t exactly premium, but given that a high-quality dualband filter can cost almost as much as an entire Seestar, I’m not complaining!
Here’s The Pacman Nebula with just five minutes of integration. The level of detail is good for such a short time, but due to the object’s location in the sky some extreme field rotation artifacts are creeping in already.
And 30 minutes on The Cocoon Nebula. I think this is really quite good from a city centre, and all it took was a few clicks.
Solar System targets
What about planetary imaging? The Seestar S50 has a focal length of 250mm and an aperture of 50mm. This isn’t really sufficient for getting good photos of planets, but it is possible to glimpse some details. Here are pictures I took of Jupiter and Saturn:
You can just about make out some details, but don’t expect breathtaking results. This telescope is designed for deep sky targets, and that’s where it performs best.
Let’s turn our attention to the Moon and Sun, which are two targets so bright that they’re not really affected by light pollution. The Seestar app has a lunar mode, and this produces good results. Here’s a 10-second video, so it’s giving a real-time view. Look carefully and you can see shimmering caused by the light passing through Earth’s atmosphere.
What about that solar filter? It works surprisingly well, although my Seestar did have trouble finding the Sun in the first place, so I had to move it using the app’s manual controls. Here’s another 10-second video:
Conclusions and recommendations
It’s time to draw these thoughts together. First, I’m going to rate the Seestar compared to the four main tenants of my Urban Astrophotography approach:
Make it as easy as possible to collect data.
Yes, for sure, the Seestar S50 is excellent in this regard.
Develop image processing skills, because they’re as important as the data you collect.
You can actually do this with the Seestar. The default option is for the Seestar to do some basic processing automatically to produce an integrated image, but there’s an option to save all the exposures (subframes). If you do this then you can process the data yourself in whatever software you like, such as PixInsight.
Aim for long total integration times.
This is where the Seestar falls down. Field rotation makes it very challenging for the kind of integration times needed for high quality city astrophotography — but basic imaging is certainly achievable.
Have fun!
This depends on what you count as fun. If you like imaging with a minimum of hassle, then the Seestar gets top marks. If you’re the kind of person that likes tweaking all the settings and modifying their kit, then the Seestar might fall short for you.
So, should you buy a Seestar S50 for astrophotography from a city? That depends on what you want from it.
If you’re a beginner and want to dip your toe into the hobby to find out if it’s for you, then I think that the Seestar S50 is a brilliant option. It’ll give you a good taste of astroimaging, and you can save all the subframes to have a go at processing too. It’s as gentle an introduction to the hobby as you’re going to get. You could even use it not just for conventional imaging, but for Electronically Assisted Astronomy (EAA), which is essentially making short integrations of just a few minutes to glimpse targets you’d never be able to see through a telescope eyepiece from a city. If you find that the Seestar’s not for you, then the second-hand market is going to be very receptive to these units for a long time, so keep it in good condition and you’ll be able to sell it on without much trouble. I get asked for beginner telescope recommendations fairly regularly, and from now on I’ll be pitching the Seestar S50 as an option that should be seriously considered. That’s probably ZWO’s strategy with the Seestar, actually: treat it as a gateway drug into astrophotography, and then converts will spend the big bucks on ZWO hardware later on.
What if you’re a beginner but you’ve got deep pockets and really want to go all-in from the start? You might find the Seestar S50 to be a bit limiting. Perhaps a more conventional imaging rig would better suit you. In terms of a telescope, I recommend an Askar FRA400 — but note that telescope alone costs about twice as much as the entire Seestar S50 kit. Add in a mount, camera, plenty of accessories, and you could likely buy eight or more Seestars! That’s not an exaggeration; the Seestar really is good value. However, following this traditional route will not only give you headroom for much higher image quality, but also provide you with a solid understanding of the concepts that underpin astrophotography. This is because you’ll need to comprehend aspects like mounts, balance, alignment, filters, guiding, and countless more that the Seestar takes care of automatically. This knowledge is powerful indeed, and it’s useful to understand concepts from first principles. You won’t get that to a deep level with a Seestar.
And finally, what if you’re an experienced astrophotographer that already has an advanced imaging rig? Then the Seestar is a harder sell, but still potentially useful. I’m going to use mine as a portable set-up for if I ever manage to travel to darker skies. (I don’t ever move my main rig to dark skies — see Controversial Opinion #5). You won’t produce images that rival a more professional setup, but you can still have fun. It’s also a great tool for outreach from a city, and I’ve written a guide to using the Seestar for outreach star parties here.
Final thoughts
There are a few extra things I want to flag to round out this review.
- I think ZWO should receive credit for pumping our firmware and app updates at a furious pace. Not just bug fixes, but whole new features. While writing this review, a new update has dropped that introduces, among other things, a timelapse mode. Already I’m thinking it might be fun making a video of sunspots moving over the course of a day.
- A focal length of 250mm may make you think that this is a wide-field instrument, but it has a tiny sensor, so your actual field of view is pretty small. Coincidentally, almost exactly the same as my Askar 130PHQ 1000mm telescope combined with ASI2600MC Pro APS-C camera.
- The Seestar has a “Scenery mode” for terrestrial use, but I haven’t tried this yet.
- Thinking back to my earlier comment about a more traditional imaging rig being better at teaching you first principles and the basics, I can’t help but wonder if that will become a thing of the past. There’s no denying the power of these smart telescopes, and perhaps they’ll become the standard in the near-future. In which case, knowing how to polar align may become obsolete knowledge. That’ll make some people sad, but I say embrace the future! We’re not at that stage yet though…
- There are lots of clever people out there playing with Seestar units, and I expect mods and hacks to appear that boost its capabilities.
- I wish ZWO had a way to allow proper framing of a target, combined with negating field rotation. You can’t really do that with an alt-az system, such as the Seestar uses, but — and I’m thinking aloud here — is there a creative solution? Maybe mount the camera sensor on some kind of automated Lazy Susan that physically rotates it to counteract field rotation? That might be impossible, but if a future-generation Seestar unit can overcome this issue and allow for easy multi-night imaging projects, that would be a real game-changer for urban astrophotographers. Come on ZWO, I believe in you!
Other Urban Astrophotography content you may be interested in…
Guide: Using a Seestar S50 for public outreach star parties
OSC vs Mono from a city
Gallery of images taken from a light-polluted city centre
How to get long integration times
10 controversial opinions
Seestar S50 gallery
All images taken from a Bortle 8 city centre, and are direct from the Seestar (no extra processing).
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‘I think ZWO should receive credit for pumping our firmware and app updates at a furious pace. Not just bug fixes, but whole new features.’
ZWO was able to do this by leveraging code from the ASIair platform, while doubling down on something they did in the ASIAir: Leveraging open source codebases like Stellarium Web Engine, SEP, Siril, Astrometry.net, and others, without honoring the licenses of those software libraries unless forced to do so.
What are your thoughts on this? Should they get this ‘credit’ when they’re ultimately denying their customers the intended benefits of the code they used to make a for-profit product? The open source spirit they are benefitting from is deliberately taken away from the same kind of enthusiasts that made their product entirely possible.
Hi Bill, thanks for your message. I don’t know enough about this to have an informed opinion. If licences were breached then that sounds like a legal issue for the wronged parties to pursue should they wish.
Open Source authors don’t have a stable of lawyers at the ready unfortunately so ZWO can take advantage at whim
any recommendations for a larger travel tripod ?
Hi Carl, I give a tripod recommendation in my guide to using a Seestar for public outreach star parties. Another option I think would work well would be something like this Manfrotto Element MII, although I haven’t personally tried it so can’t offer any guarantees. The Seestar is quite light, so you don’t need a very heavy-duty tripod, although you certainly don’t want it to be wobbly. Note that photo tripods generally come with 1/4″ screws, while the Seestar takes a 3/8″, so you’d need an adapter. This is covered in the public outreach guide I linked to.
I wonder if the alt/azm problem might be solved by uswa wedge. I had excellent results with a wedge on a 8″ Meade alt/azm tripod which effectively turned it into an equatorial mount.
Oh interesting. I suspect the Seestar would need a firmware upgrade to allow it to not use its internal tracking system and delegate tracking to a mount.
Hi Lee! I’m brand new to this hobby and curious if in your opinion this scope would produce decent images for someone living in a Bortle 8 zone like Brooklyn, NY
Hi Vinny, I shoot from a Bortle 8 city too. You can certainly produce decent images with a Seestar. The trick is to collect data on a single target for several hours, resisting the temptation to hop around and spend just a few minutes per target. This longer integration time will allow you to combat light pollution and get a better signal-to-noise ratio, which in turn results in a better quality final image.
Awesome, thanks for the reply Lee!
Correct me if i am wrong.. What if i put the seestar S50 on an old Manfrotto ART with its 144b photohead inclinated (ln my case 52° to the north)
Then i will have an equaterial mount on wich it can operate fine without any software?
That was an amazing guide thanks! 🙂
Thanks, very informative, i will stick to landscape and wildlife shooting. You save me a lot of money.
The initial setup of the product says that the app requires access to my photo album in order to work properly. Why? The privacy policy says that personal information will be protected but gives multiple reasons for overriding that policy. Also that goes for any information given them. After the Tic Tock news about security concerns including location information I’m concerned about this.
I think that the app needs access to your photo album because that’s where it saves images.
Do you have any recommendations for a dust cover and Bahtinov Mask for the Seestar S50?
Hi Bill, I find that the default autofocus routine works well, so I don’t use a Bahtinov mask. And when not in use I put the Seestar in its case, so there’s no need for a dust cover. A lens cap isn’t needed either, as the lens is safely out of harm’s way when the unit is powered down.
If you want a lens cap and a Bahtinov mask for the SeeStar S50, Agena Astro sells both. I got both of them for my SeeStar S50.
Thank you for the review, I haven’t got a telescope yet so was intrigued with this digital unit, I’ve been taking still photos for 50+ years, at the moment I’m in a envious position , a 30 minute drive will eliminate most if not all urban light pollution , was trying to find a set up that will take very decent pictures of the planets, maybe not Pluto {still a planet in my book} but certainly mars and Saturn, any suggestions , TIA
Hi Robert, to take photos of the planets you need a longer focal length telescope. I don’t believe any of the smart telescopes currently available on the market really have the right specifications for planetary.
Thank you for the insightful review. I have a Unistellar that I really enjoy. But the SeeStar seems like it would be a great grab-n-go version.
I am wondering why the alt/az rotation artifacts can’t be reduced in software. I know the corners would still suffer. But even corner drop-out could be addressed by taking advantage of the position control and some intelligence to recapture missing stars in the corners. And yes, there may also be some complications due to flatness of the optics. Again perhaps some AI could be applied to correct that. For example train the image processing system by mapping the nonlinearities of the optics, again using the position control to take multiple images of a star field that has been positioned in various portions of the field of view. Then calculate the corrections from the apparent distortions.
I would like to see a feature to stitch together a larger field of view.
One artifact that bothers me about the Unistellar and now seems to also be in the SeeStar is the encoding of star intensity as size. I.e. brighter stars seem to be represented as larger disks. The emphasis seems to be related to using stacking to enhance light gathering and brightness. I would be more interested in using stacking to enhance resolution, which might improve planetary and lunar images.
I like how you’re thinking of clever ways to get around the problems! A robust mosaic system could do the trick. Maybe with an option to spend ~80% of the imaging time on the central portion of the image, and 20% gathering data from around the edges. So you wouldn’t have good detail around the edges, but you’d have proper stars rather than field rotation artifacts. Regarding planetary in particular, you can’t really get around the fact that a 50mm aperture / 250mm focal length telescope just can’t resolve that much detail on objects that appear to be tiny. Maybe these companies will design different smart telescopes with planetary in mind.
Great review, especially from a light polluted area.
I was wondering if you had a chance to compare the Seestar to the original vespera. I am asking becuase open box and used ones are being sold for around a $1,000 or so.
Thanks,
Jason
Hi Jason, good question. I’ve never used a Vespera, so can’t offer a particularly informed opinion. For what it’s worth, having looked at the specs, I think that the Vespera may have a slight edge but not enough to justify the higher cost (even considering open box / used). Personally, I’d go for a SeeStar.
Thanks. Does the Seestar split double stars? I have been trying to figure it out.
I have been trying to convince myself not to buy the Seestar (I like the idea of for once not getting something made in China), however I have constantly failed. I like that Unisteller has the citizen science projects but since it looks like their scopes (except the Odyssey which no one has reviewed yet) need to be constantly adjusted I am not sure its a good option. Especially since their light pollution solution is not a filter but software.
I haven’t actually tried it for splitting doubles. I guess it won’t be great because of its small aperture and focal length, but it should handle some at the easier end of the spectrum.
It sounds like you’ve got a bad case of analysis paralysis! If you think you’d have a fun time with the Seestar then go for it. You can sell it on quite easily if it doesn’t meet your expectations.
Yes I know I do. Analyzing all the features is the smart telescope version of aperture fever. Got permission from wife and will pull the trigger before she changes her mind. Unlike Moses I won’t be saved by the red sea if pharaoh decides she made a mistake and we need the money for something else.
I wonder if the celestron origin will be a lot better
Oh I’m sure it will be, but that’s to be expected given it costs about £4000 compared to £539 for a Seestar.
I just got the SeeStar. I wish thay had more comprehensive instructions for us dumb, technologically impaired dudes. I did see a you tube video, where a man bought a equatorial mount, then made a equatorial wedge. Me being technologically impaired, I thought it looked as if it worked great.
ZWO are doing a great job of supporting this scope. They have said they plan to add an equatorial mode (the scope currently works well on a wedge, but you have to be careful to select objects above what the scope sees as the horizon. Equatorial mode will fix this problem). They also plan a mosaic mode for larger objects.
Great guide! The seestar looks good, but feel like I’d be wanting more. As a photographer with a high-end mirrorless camera now (Canon R5), are there any scopes that do something like the seestar but could still let you use a better camera sensor? Sorry, probably a stupid question, but I would like to leverage the gear I already have if possible.
Today I simply point my 200m w/ a 2x extender (making it a 400mm f5.6) along w/ the canon is pretty good, but everything is manual and a ton of work to get usable images. I like the idea of just managing everything w/ your phone but would to swap out the sensor w/ something better.
There might be some T adapter you could use, but speaking as someone that’s come from using camera sensors, proper astrocameras are a lot better for astro work. Having a cooled sensor is a big plus and allows for proper calibration, for example. Personally, I think regular cameras are best used for widefield astro landscapes, and dedicated astrocams are really the best option for everything else. In any case, there’s not an easy all-in-one Seestar-but-use-your-camera-sensor product out there that I’m aware of.
Hi im thinking of getting into astrophotography and im looking for a good beginners telescope this ZWO seestar50S sounds good. I live in regional south Australia. We get great dark skies out here especially of milky way ect would this telescope be good for that type of photography and picking out more of our closest stars eg southern Cross . I’m a complete beginner in this field. We have the international sky park down the road at Sedan SA. And BIG Bend sky park where it’s just awesome.
I have a Samsung galaxy S23 our WiFi is 3 G
Can anyone please give me some info if the ZWOseestar S50 be ok for someone like me. Jane
Hi Jane, the Seestar is a good way of trying astrophotography. It’s relatively cheap (astro is an expensive hobby!) and designed with beginners in mind.
Seestar has revived my interest in night sky gazing. 30 years ago I bought a Mead but soon realised that UK skies where I lived were not suitable and lost interest after observing dark skies in the Drakensburg Mountains in South Africa! So I sold it. Then Covid hit three years ago and my isolation in a rural area drove me to tool up with a Skywatcher goto plus lots of very expensive eyepieces – some of which actually costing more than a Seestar! During and after Covid I persevered but lost interest – poor viewing and complicated set up turned off my interest. I contacted my local astro club who suggested the Seestar. I bought one and within a week had sold my previous gear costing 10 times the Seestar. It is an absolute revelation as I can see deep space objects and send their images to friends and my grandchildren. Its portability is such that I am in France right now in a Bortle 3 zone with clear skies capturing some impressive images. Yes you need at least 45 mins stacking . I was able to pack it into my Ryanair cabin bag with my clothes etc so its small size and weight are not a travel hindrance.If night skies are overcast just observe the Sun in the daytime – very clear detail of the sun spots and see how they gradually move and change through a day.
I bought a leveller and a lens cap and dew extension but have since found the dew heater effective and the tripod legs if you dont extend them can be twisted to adjust the level down to 0.1 which is well into its required setting up. The images are spectacular and way better than examples seen commercially. Videoing the Moon at 4x is fun for my grand kids. One of them is autistic and an astro savant – show him any object in the sky – Galaxies, Messiers NGCs etc and he will name them everytime. At 6 years old he cannot join an astro club yet as none accept children under 12 it seems. So Seestar has had a real impact for me and my family and friends.
It’s a brilliant piece of kit isn’t it. I wonder what improvements will be made in future generations of Seestars!