As you know, prime lenses come in a wide range of sizes and focal lengths, and every once in a while, one comes along and seems to grab you by the scruff of your neck. One such lens is the Viltrox AF 16mm f/1.8 FE, which is an impressive and useful lens for astrophotography thanks to its wide-angle field of view and fast maximum aperture.

This lens is one of the wider prime lenses that are available and could be one of the best third-party lenses for astrophotography. With a price of just $464 (£533), this is one of the most cost-effective wide-angle primes, but rather than being a second-rate lens, its build quality and image quality are fantastic. It’s not the best, but it’s undoubtedly a lens you would enjoy.

Image quality is excellent overall, with no need for lens corrections, except for vignette removal when shooting wide open. With near-perfect sharpness and minimal distortion and aberrations straight out of the camera, perhaps the weight of the lens is a small price to pay.

The lens is made up of 15 elements in 12 groups and is built like a tank, with an all-metal body. It is pretty heavy, though, weighing in at 19.4 oz (550 g) despite its relatively compact size. Attach this lens to one of the best Sony cameras and you will have a formidable combination. The 16mm f/1.8 is also available in the Nikon Z-mount.

Viltrox AF 16mm f/1.8 FE lens review

Viltrox AF 16mm f/1.8 FE: Performance

• Great image quality
• Impressively sharp at f/1.8
• Excellent corner sharpness

With a focal length of 16mm and a maximum aperture of f/1.8, this is clearly a great lens for astrophotography from a technical point of view. The light-gathering capabilities are excellent, to say the least, and during testing it was possible to shoot at a range of ISO levels with a moonless sky. Even ISO 800 was often high enough for a correct exposure.

The image quality produced by the 16mm f/1.8 is great, with excellent levels of sharpness across the frame. What’s most important here is that even corner sharpness is fantastic when wide open at f/1.8. This is the aperture setting where vignetting is at its strongest, but it reduces drastically when you stop down to f/2.8 and is completely gone by the time you stop down to f/4.

Luckily, though, there is a lens profile in Adobe Camera Raw and Adobe Lightroom that completely removes vignetting. There’s also only minimal chromatic aberration and a tiny amount of barrel distortion, which is impressive given the wide field of view produced by the lens.

As mentioned before, sharpness is great wide open and improves incrementally as you stop down up to the sweet spot of the lens, which is f/8. Sharpness drops slightly at f/11, and it’s at f/16 where diffraction begins to soften the image overall. This increases further when you stop down to f/22.

These latter apertures aren’t relevant to astrophotography; the medium ones aren’t either but the sharpness produced at f/1.8 and f/2.8 is exactly what you want.

Viltrox AF 16mm f/1.8 FE: Design

• Weather-sealed build
• Compact yet heavy
• Great handling

The 16mm f/1.8 lens is something of an oddity in one respect: it’s both compact and heavy considering its size, although this comes down to its optical construction. The lens weighs 19.4 oz (550 g) with a size of just 3.35 x 4.06 in (85.2 x 103 mm). It does, however, balance well with Sony A-series cameras.

The 16mm f/1.8 is made up of 15 elements in 12 groups, including four ED glass and three aspherical lenses. The optical construction is designed to deliver sharpness, detail and high contrast with minimal distortion. It’s fair to say it achieves these. Of course, you will experience some perspective distortion when tilting the lens up to capture more of the night sky when there are ground elements in the foreground.

Unlike some wide-angle lenses, the front element isn’t bulbous, and it features an HD nano multilayer coating with a water-resistant and antifouling coating. The filter thread is also just 77mm, so you can easily attach screw-in and square filters if you use them for your astrophotography.

The minimum focusing distance of the lens is 10.6 inches (27 cm), which is great for landscape photographers but less important for astrophotographers.

Build quality is impressive thanks to an all-metal body and weather-sealing. This gives the lens a premium look, and it feels robust in the hand. There’s also a useful digital color screen that displays lens information.

When it comes to controls, there are possibly a few more on this lens than you might find on the average prime. There’s a manual focusing ring that’s wide enough for use when wearing gloves, a manual aperture ring that can be set to stepped and stepless operation using a switch on one side of the lens, two customizable Fn buttons and an AF/MF switch.

Viltrox AF 16mm f/1.8 FE: Functionality

• Small color digital screen
• Customizable Fn buttons
• 105.6-degree field of view

The Viltrox AF 16mm f/1.8 FE is a full-frame lens offering a generous 105.6-degree field of view, allowing you to capture more of the night sky. This lens naturally works with all Sony FE bodies, and if you shoot APS-C, it will give you an equivalent focal length of 24mm. This means if you currently own an APS-C camera but plan to upgrade to full-frame, this lens could comfortably join you on that journey.

As prime lenses go, this one has a few more bells and whistles than most, so there are a few more things to talk about than usual. Focusing is internal, so the front element doesn’t rotate or extend outwards, which is great when using filters.

For astrophotography, manual focus is the only way to go, but this lens also has autofocus for when you’re shooting other subjects. The autofocus isn't the fastest we’ve seen, taking about 0.25 seconds to lock onto subjects when the lens is wide open, or 0.5 seconds when stopped down. This is driven by an SMT stepping motor, which is quiet but audible.

One feature that you don’t see on many lenses is a small color digital screen on the top of the lens. This shows the focus distance, aperture setting and the active Fn control. Is it a gimmick? A bit. Is it useful? Yes. For astrophotography, the screen is definitely useful because it’s illuminated.

As with most Viltrox lenses, there’s also a USB-C port on the lens mount so it can be powered. This allows you to connect the lens to the Viltrox Lens app via Bluetooth to update firmware and customize the Fn buttons and the digital screen’s welcome screen. This makes firmware updates incredibly easy, which is a great feature to have.

Viltrox AF 16mm f/1.8 FE: User reviews

In online reviews, users consistently highlight the lens's value and image quality. Build quality comes up time and time again, thanks to the all-metal build.

Many users report that overall, the lens offers much more than you’d expect for the price and even more than some more expensive lenses.

How we tested the Viltrox AF 16mm f/1.8 FE

The Viltrox AF 16mm f/1.8 FE was tested in combination with the Sony A7R V, which offers an unforgivingly high resolution. The lens was tested at night with a focus on astrophotography, and in daylight to assess sharpness, distortion and general functionality for an all-round approach to testing.

Should you buy the Viltrox AF 16mm f/1.8 FE?

Since there are only a few alternatives to the Viltrox AF 16mm f/1.8 FE, and given that it offers excellent value for money, this is absolutely a lens worth considering if you need a wide-angle prime.

Furthermore, you’ll struggle to find a similar alternative with the same balance of overall build quality and price. Image quality is excellent, even in the corners and edges of the frame when shooting wide open with minimal distortion.

The two customizable Fn buttons and the illuminated color screen that provides useful lens information are extremely helpful when shooting in the dark.

With a price of $464 (£533) and given its build quality, image quality and overall handling, this lens represents excellent value for money. And while it may be a full-frame lens, APS-C users can still enjoy a 24mm equivalent focal length, so it’s a useful lens for astrophotography whichever format you shoot with.

This is a professional-quality lens with a mid-range price tag, and like other Viltrox lenses, you get the lens, a lens hood, front and rear lens caps and a soft lens case in the box.

If this lens isn't for you

The Viltrox AF 35mm f/1.2 LAB FE is a slightly less wide Viltrox lens with a much faster aperture and is part of the company’s flagship LAB series.

The Sony FE 20mm f/1.8 G is a fantastic wide-angle prime offering excellent image quality in a compact and lightweight form factor.

The Sigma 14mm f/1.4 DG DN Art is something of a beast, both in terms of specs and its size. With a 14mm focal length and f/1.4 maximum aperture, it’s perfect for astrophotography.

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The best stargazing apps can take your observation of the night sky to the next level, whether that's using augmented reality (AR mode) to identify stars or looking up the next lunar eclipse.

However, the bright light emitted by smartphone screens can prevent your eyes from adjusting to the dark. If you're using one of the best telescopes, you'll want to preserve your night vision even more. Fortunately, there are ways to all but eliminate this problem.

Why are bright screens bad for stargazing?

When you step out into the dark, it can take up to 20-30 minutes for your vision to adjust. The rod cells in your eyes build up a chemical known as rhodopsin, which gives you night vision.

However, bright light bleaches that chemical, negatively impacting your night vision. So when you look through a telescope, binoculars or just turn your eyes to the night sky after peering at a bright phone screen, it'll be harder for you to pick out fainter objects such as galaxies and nebulas.

One way of fixing this problem is simply to put your phone away and wait another 20-30 minutes. But if you're using a stargazing app to help you navigate the night skies, that's not really an option.

The good news is that, between individual stargazing apps and your phone's own built-in features, you can minimize the impact of your smartphone's screen light.

How to block white light in stargazing apps

Many of the best stargazing apps will let you enable a red light filter or similar, though this option may not always be present in the free version. Here's how to do that in three of our favorite stargazing apps:

SkyView: Tap the screen, tap the horizontal lines, tap on Settings, then Display, then Night Mode and Red.

Star Walk 2: Tap the horizontal lines, tap on Settings, then tap the button next to Night Mode.

Sky Tonight: Tap the horizontal lines, tap on Settings, then Tools, then Night Mode.

All these modes will minimize the amount of white light coming from the app. However, be aware that this is only within the app. Once you go back to your phone's main menu, it will be at full color. With the red screen naturally looking darker, you may have turned up the brightness on your phone, so making the switch away from the app will be quite the shock.

If you want to dim your whole phone or put it into red light mode, here's how to do that on Android or iPhone.

How to block white light on Android phones

On Android, there are several ways to minimize the impact of bright light, depending on the model and make of phone you have.

One near-universal option is to dim your smartphone. Swipe down the notification panel from the top of the screen and you'll see a brightness slider. Slide this to the left to dim your phone.

We'd also recommend disabling adaptive brightness in the Display section of your phone's settings. You may also have an Extra Dim option in the Accessibility menu — just don't dim the screen to the point of not being able to see it at all!

Some Android phones, such as recent Samsung and Google Pixel models, also offer a Red Filter. On some, you'll find this in Accessibility, then Vision Enhancements, then Color Filter. You can then choose the color you want and also tweak the opacity.

All the above options will let you continue to use your smartphone for stargazing, while minimizing its negative impact on your night vision.

How to block white light on Apple iPhones

As with Android phones, iPhones have a built-in option to dim the screen brightness. In this case, you swipe down from the top of the screen and look for the vertical brightness slider, represented by a sun icon. Reduce the slider as much as you're comfortable with, dimming the screen while still keeping it visible.

Beyond that, recent iPhones also offer the ability to apply a color filter, again via their Accessibility options. Here's how to do that.

First, tap on the Settings icon, then pick Accessibility. Select Display & Text Size and go to Color Filters. Tap the Color Filter button. Then, pick Color Tint and move the Hue and Intensity sliders all the way to the right.

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Want to educate young children about the wonders of the cosmos? Depending on the time of year, your location and the weather, your hopes to see the night sky in real life might not be as easy as heading into the backyard and peering up. That's why one of the best star projectors might be the solution.

That's why we've picked out six star projectors that actually deliver scientifically accurate images, from projections of the northern hemisphere to breathtaking pictures from the Hubble Space Telescope.

Any one of these will turn your home into a private planetarium. Each comes with several swappable images, and you can purchase additional slides/discs for the Homestar and Pococo models. If you're seeking to stimulate a child's interest in space and STEM or just take your friends on a journey through space, these are the scientifically accurate projectors to purchase.

Whether you are a seasoned astronomer or a newcomer to the hobby, the best stargazing apps have the potential to seriously enhance your skywatching experience. But it's easy to overlook just how useful these portable programs can be.

That's why we've put together this guide to getting the best use out of stargazing apps, from identifying stars and constellations through to seeking out dark sky sites and beyond. You will wonder how you ever managed without them.

So read on and get ready to take your stargazing to the next level. And if you're wondering how else technology can take the work out of skywatching, we've also rounded up the best smart telescopes.

Using stargazing apps

Before we explore specific uses, there are a few things you need to know about using the best stargazing apps on your Apple or Android device.

Firstly, while some apps support offline use, you'll typically need a mobile or Wi-Fi signal with data to make the most of these apps.

Also, some apps lock certain features behind a paywall. Pay for Stellarium Plus, for example, and you get an additional 2 million deep sky objects, the ability to connect to certain telescopes and more.

Finally, while many stargazing apps are relatively intuitive, we'd recommend you familiarize yourself with them at home before taking them out into the field.

Identifying stars in the field

One of the most common and convenient uses for stargazing apps is identifying stars, constellations and more, just by pointing your phone's camera at them.

It really is that simple. Take Sky Tonight, which we think is the best stargazing app for AR (augmented reality). Launch the app, grant it camera access and turn it towards the object you want to identify. The name will appear on screen and you can also tap to learn more about it, whether it's a star, constellation, planet or nebula.

Conversely, you can also use the app to find specific objects in the sky. Want to view Uranus at opposition this Nov. 25 but aren't sure where to look? Search for it in Sky Tonight and the app will point you to it.

Identifiying stars from photographs

Being able to identify night sky objects in the field is a real boon, but what if you've already taken a photograph and want to identify which stars were visible?

That's where apps like Sky Walk 2 come in. If possible, you should return to the location where the photograph was taken, but if that's not possible, you can input GPS co-ordinates and Sky Walk 2 will show you the view from that location.

Next, using the clock icon and slider, alter the date to the exact time you took the photograph (or as near as possible). You will then be shown the night sky as it was at the time. You can now tap on the star or stars you want to identify and Sky Walk 2 will tell you the name.

Sky Walk 2 isn't the only app to offer such a facility, but in Sky Walk 2's case this feature is present in the free version of the app.

Finding dark sky sites

It's a sad fact that light pollution has made it harder for astronomers to study the night sky. While the planets in our solar system are still visible, sky glow obscures more distant objects, such as fainter stars.

You could travel to a dark sky reserve but, with the aid of one of several stargazing apps, it is also possible to find dark sky sites closer to home.

Apps like Sky Safari and the simply named Light Pollution Map will show you the light pollution levels locally and globally, estimated on the Bortle scale. The latter app colors the map, with pink the most light pollution and black the least.

In just a few seconds you can find out how light polluted your local area is, and use the map to find a location nearby where the sky is dark, or at least darker.

Planning a stargazing trip

Are you planning a stargazing trip? Then you'll be happy to hear there's an app for that. There are several, in fact, but Sky Safari has all you need to plan your next outing. You can create observation lists, find out when and where objects are visible, and while it won't book your tickets for you, it comes close.

Our reviewer Jamie Carter used the app to plan his observations of conjunctions, specific moon views and astrophotography opportunities. Coupled with its light pollution map, it will be a huge help in putting together an itinerary for your skywatching trip.

Troubleshooting stargazing apps

Hopefully you'll have a smooth experience, but if you're having issues, here are a few things to try.

• Take your phone out of its case. Magnetic clasps can interfere with internal sensors.
• Make sure location services are enabled. Many apps use GPS to show you the correct view.
• Check your phone's clock. If your clock is not set accurately, apps may display an incorrect sky
• Swoop your phone in a figure eight motion. This can help calibrate your phone's "compass".
• Make sure you have a signal, and that data is enabled. Unless the app has an offline mode you will still need a connection. Signal may be poor at dark sky sites.
• Check each app's permissions. Location aside, Augmented Reality (AR) stargazing apps will need camera access.

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