Astronomy Now - January 2021

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Ade Ashford

Futuristic astronomy: Vaonis Stellina ST 80

observation station

s any student of telescope history will know, France has a long and distinguished tradition of

optical innovation that now extends into the twenty-rst century. In a recent review of the

eVscope (AN, August 2020), I described how Marseille-based company Unistellar used a successful

2017 Kickstarter crowdfunding campaign to turn their ‘Enhanced Vision’ telescope concept into a

commercial product. e eVscope is a self-aligning computerised telescope capable of displaying

near-realtime colour images of galaxies and nebulae via its built-in electronic ‘eyepiece’, or on the

screen of a controlling smart device via Wi-Fi.

e eVscope was conceived in 2015, but the following year saw the founding of a competing French

company called Vaonis, by Cyril Dupuy, a start-up entrepreneur with a background in optics and

aerospace. Vaonis were also working on their own fully automated, self-aligning telescope system,

again using a smartphone or tablet to both control the instrument and view its output on-screen.

Vaonis’ product eventually came to be marketed as the Stellina ST80 observation station, the

instrument reviewed here.

Vaonis’ idea of what the all-singing, all-dancing personal robotic telescope should look like and how

it should perform is quite a departure from Unistellar’s eVscope. Stellina is, rst and foremost, an

astrophotographic instrument, primarily for deep-sky objects. It’s targeted at rst-time users wishing

to capture detailed images of nebulae and galaxies with the absolute minimum of effort, either to

view on a smart device or – if you like to dabble in image editing – save in a variety of formats to a

USB memory stick for subsequent processing on a desktop computer. More on this later.

e optical heart of Stellina is an 80mm ED doublet lens of 400mm focal length, hence it’s an f/5

system. While this may not seem a particularly ‘fast’ optic in conventional photographic terms, it is

par for the course for refractors intended for astrophotography of extended objects like nebulae and

galaxies. Remember that this is a doublet objective lens, albeit one made using high-index, low-

dispersion lanthanum glass that reduces chromatic aberration for improved colour delity. Stellina is

also self-focusing at the start of an observing session, so you never have any excuse for a blurry

picture.

Stellina isn’t intended to be used visually, so an electronic detector lies at the focus of the objective

lens. Vaonis chose a colour Sony IMX178 CMOS sensor delivering a eld of view of almost 1.25

degrees across the diagonal, which is similar in extent to the Pleiades star cluster, for example. Given

that most of us have the misfortune of living under some form of urban light pollution, Stellina

incorporates a CLS (City Light Suppression) lter. Furthermore, the instrument has built-in

humidity and temperature sensors, so if Stellina senses that the night air may be falling below the

dew point, it activates a built-in lens heater!

Vaonis markets Stellina as a complete ‘observation station’ incorporating all the elements needed for

astrophotography. is means that it must have a way of aligning itself by the stars and, once a

desired target is selected on your smartphone or tablet using the dedicated Stellinapp (more on this

later), precisely tracking that object for long periods of time – up to an hour or more, if necessary.

Self-alignment and tracking is accomplished by an embedded computer and a motorised alt-azimuth

mount. Stellina is also cable-free and self-contained, powered by a rechargeable battery pack and

operated via Wi-Fi.

First impressions

Stellina arrives at your door in a single shipping carton measuring 90 × 58 × 31 centimetres. Once

opened, you’ll nd the instrument’s day-to-day storage case, which is a glossy black box 62 × 46 × 19

centimetres in size, emblazoned with the words ’Stellina: share your universe’ and sporting a carrying

handle on the top. ere’s another 15 × 15 × 29 centimetre box for the Gitzo GT3520S-VS1 tripod.

e tripod box also contains a bubble-level plate, a few Allen keys for making tripod adjustments, a

rechargeable PowerCore Li-ion battery pack for Stellina rated at 10,000mAh/36Wh, and some USB

adaptor cables. A tripod adaptor with a bubble-level plate on top connects to the base of Stellina via

a standard 3/8-inch photo thread.

e supplied Gitzo tripod is very stubby indeed compared to those that come with conventional

telescope mounts. With its two-stage carbon-bre legs fully extended, the top plate is just 37

centimetres above ground level! e very low operating height of Stellina does mean that you

occasionally have to give some advance thought as to where you should place the instrument,

particularly when your target may lie close to the horizon – you won’t see over the fence! For

operating in the country or a secure park this isn’t much of a problem as you often have more choice

in your sight lines. Stellina’s built-in dew heater is certainly needed for long grass.

Nestling inside its foam-lined storage box, Stellina is shipped with a dust jacket made of a stretchy

black Lycra material of a type used for the shrouds covering the open framework of truss-tube

Dobsonians. When closed for storage, Stellina’s case measures 47 × 39 × 12 centimetres and tips the

scales at 11 kilograms. Given that the instrument has a curvaceous design of smooth white plastic, I

do question Vaonis’ wisdom of using such a slippery material for a dust cover – if one is not careful

then Stellina could slip through your hands!

With Stellina safely attached to the supplied Gitzo tripod, the entire instrument stands just 86

centimetres tall. It’s certainly an eye-catching and tactile conversation piece – almost sculptural –

when sitting in the corner of a room. I joked with my youngest daughter that it was a new domestic

robot, because when switched off there is nothing outwardly to suggest it’s an optical device. (e

instrument is unsettlingly reminiscent of EVE and some of the service robots in the 2008

Disney/Pixar movie WALL-E; one almost expects Stellina to suddenly announce itself in a thin,

reedy voice.)

Getting technical

As I touched upon earlier, at the heart of Stellina is an 80mm, f/5 ED doublet lens utilising

lanthanum glass for superior colour correction. Instead of an eyepiece, a colour Sony IMX178

CMOS sensor with a matrix of 3,096 × 2,080 pixels lies at the focus of the 400mm focal-length

objective. e IMX178 has 2.4-micron (0.0024mm) pixels, hence the sensor’s overall dimensions are

7.4mm × 5.0mm, which gives Stellina a true eld of one degree by 0.7 degree, or almost 1.25

degrees across the diagonal. Furthermore, the small pixels give the instrument a resolution of around

1.25 arcseconds per pixel, which means Stellina achieves optimal image sampling for typical two- to

four-arcsecond FWHM seeing.

On paper, then, Stellina’s specication suggests that it can deliver images at the theoretical resolving

power of its 80mm-aperture objective under normal atmospheric conditions. In addition to the built-

in CLS light-pollution lter and dew heater, it clearly indicates that a lot of thought went into the

design from a team well versed in astro-imaging. Furthermore, since Stellina uses an altazimuth

mount, the engineers at Vaonis incorporated a de-rotation system to prevent those stars near the

edge of the eld forming short arcs instead of points as the eld orientation changes throughout the

duration of the exposure, operating in precisely the same way as professional astronomical research

telescopes.

Powering Stellina

On one side of the instrument there is a battery compartment with a cover that pops open and lifts

out at the bottom where a tab holds it in place. e tab has a small aperture at the end, large

enough to accept a cable should you wish to power Stellina from a mains transformer supply, but

most times you will use the supplied rechargeable 10,000mAh battery pack, or one of your own with

maximum dimensions of 13 × 8 × 4 centimetres.

You will nd three USB ports inside the battery compartment, the lowest being a USB-C port used

for power input. According to the Vaonis specication, Stellina’s minimum power requirement is

2.4A at 5V. e specications state that a 10,000mAh battery should give you ve hours of

operation. In my tests, two-and-ahalf hours of operating time was the most I could achieve with the

supplied 10,000mAh battery pack, but the pack on the review model that I was sent was evidently

well used, so maybe it wasn’t working near full capacity.

e other two ports in the battery compartment are USB-A sockets for connecting memory sticks

for saving your images in JPEG, FITS or TIFF formats, the last being stored in 16-bit format

without compression for higher quality (think RAW format on a DSLR camera). To give you some

idea of the storage you’ll need, the le sizes generated by Stellina are up to 4–5MB for JPEGs,

12MB for FITS, and up to 36MB for TIFFs in full resolution.

As soon as a power source is connected to the USB-C port, Stellina’s power button on the opposite

side to the battery compartment glows blue. Pressing the power button for a couple of seconds starts

the initialisation process and the instrument creates a Wi-Fi hotspot. Up to ten smart devices can be

connected to Stellina simultaneously, but only one is designated the administrator – the other nine

can look on and see the pictures.

Stellinapp

Before you can start capturing images with Stellina, you need a compatible Android

smartphone/tablet, or an iPhone/iPad, onto which you must download the free Stellinapp from

either the Google Play Store or Apple’s App Store. e minimum Android requirement is version

4.4, or iOS 10 for Apple devices. Vaonis releases regular software updates, some of which are updates

for Stellina itself, so the rst time I launched the app I wasn’t surprised that it also patched the

instrument’s rmware, all without any issues. Another thing that you can do on rst launching

Stellinapp is to create a user prole where you can save your observation history, favourite targets and

app settings.

e app’s user interface changes depending on whether you are in the Control, Catalogue, Capture,

or User Prole tab. It’s intuitive to use and largely self-explanatory after a few minutes’ use. Control

is where you wake Stellina, or engage sleep or park mode. Catalogue is where you select targets from

a current list of about 200 objects compiled from Messier, NGC and IC deep-sky objects, asterisms,

prominent double stars, the Moon and planets, or you can manually enter coordinates. Capture is

the section of the app where you frame your compositions and start stacking sets of ten-second

exposures (called frames in Stellinapp) to form long-exposure images, zoom and pan around them,

apply simple processing before saving, and share or export your photos.

Real-world testing

As explained earlier, Stellina has a built-in CLS lter, so rather than travel out to my usual dark-sky

site, I chose to use the instrument in my suburban back garden on the edge of a mid-sized market

town, typifying the environment in which Stellina would be used. e town recently made the

switch to LED street lighting and three such lanterns lay within 50 metres of the test site, and I had

placed the instrument in the shade of the nearest light.

Once connection to Stellina’s Wi-Fi network is established in Stellinapp, which is about a minute

after booting, and after you have logged in (it’s not compulsory), you need to initialise the

instrument. e rst time that you see the central section of Stellina’s casing quietly rotate out of its

parked position and the objective lens slowly point up to the stars is quite magical! Stellina then uses

GPS geolocation to model what’s above you and then presents a catalogue of objects currently visible

using a traffic-light system: green is good to observe, amber is too low or too near the zenith, and

red is below your horizon.

Once you’ve selected the object that you wish to observe, Stellina performs a star-zone search and a

star-pattern analysis – essentially a plate-solving exercise to determine precisely where it is pointed

and how far it has to move to acquire your target. Next, the instrument performs an autofocus to get

the sharpest imagery, before engaging tracking activation. After some rather mesmerising graphics

reminiscent of particles disappearing at the event horizon of a black hole, the Capture tab opens and

you see your target slowly appear before your eyes as each subsequent 10-second-long frame is live

stacked with the previous one.

Faint emission nebulae and galaxies can take an hour or more (the Catalogue tab tells you roughly

how long you need to stack frames) to build on screen, but bright planetary nebulae such as the

Dumbbell Nebula (Messier 27) look great after 10 minutes, or 60 frames. You can replay a whole

stack of frames from the beginning, or pan around and zoom in and out of the image on your

smartphone/tablet using two-nger pinch and spread gestures, even as it is stacking. On occasion,

the app crashed on my Android phone, but once I relaunched Stellinapp I could always resume from

where I left off and nothing was lost.

Concluding thoughts

For all its technical wizardry, Stellina is remarkably easy to use and certainly does what it says on the

tin, delivering rewarding images of a wide range of deep-sky objects – many of which would be

challenging to capture using conventional astrophotographic techniques. e only downside for

Stellina is the usual one – its price of €3, 999 (about £3, 550 according to the exchange rate at the

time of writing), which many of the astrophotographic cognoscenti will regard as excessive.

However, not everyone has the time or inclination to ascend the steep learning curve of getting

familiar with astro-imaging hardware and software, so there is a denite market for Stellina and

products like it. Furthermore, you may be interested to know that Stellina observation stations are

assembled by hand by a workforce based in Montpellier, not far from the offices of Vaonis. And in

these troubled times, it is always nice to know that we are using products that support and benet

the communities in which we live, which has a different value altogether.

Ade Ashford has travelled the globe writing about astronomy and telescopes, serving on the staff of astronomy magazines on both sides of

the Atlantic.

At a glance

Size: 47 × 39 × 12cm

Weight: 11.2kg

Autonomy: 5 hours with a 10,000mAh portable battery

Aperture: 80mm

Focal length: 400mm

Focal ratio: f/5

Field of view: 1° × 0.7°

Objective type: ED doublet with lanthanum glass

Filter: CLS light-pollution, built-in

Image sensor: colour 1/1.8-inch CMOS Sony IMX178

Sensor matrix: 3,096 × 2,080 pixels

Pixel size: 2.4μm (0.0024mm)

Resolution: 1.24 arcseconds

Field de-rotation: built-in

Dew heater: built-in

Magnication: Equivalent to 50× and up to 100× with digital zoom

Mount: Altazimuth

Alignment: Automatic initialisation with star-field recognition

File formats: JPEG, TIFF or FITS (16-bit raw images)

Price: €3,999

Website: vaonis.com

The sleek Stellina, measuring 47 × 39 × 12cm, looks almost like a robot out of WALL-E. Image: Vaonis.

Do you wish to capture deep-sky images from your back garden without the steep learning

curve of traditional astrophotography? Stellina may be all you need, writes Ade Ashford.

The supplied Gitzo carbon-bre tripod is just 37cm high. The base of Stellina drops into place and is secured by the locking lever

shown.

The stubby carbon-bre Gitzo tripod supplied means that Stellina stands just 86cm high when the device is powered down or

sleeping.

Stellina’s imaging system comprises a colour Sony IMX178 CMOS sensor at the 400mm focus of the 80mm, f/5 ED double objective

shown here. The instrument is self-focusing and the lens has a built-in heating element to banish dew.

The only requirement for setting up is that Stellina stands vertically, which is easy to achieve using the built-in bubble level.

The supplied battery pack (or one of a larger capacity purchased separately) plugs into a USB-C port in the fork arm. Stellina’s

minimum power requirement is 2.4A at 5V. It can also operate from a mains transformer (not supplied), the cable running through

an aperture in the base of the battery compartment door.

One of the highlights of the summer deep-sky is the Dumbbell Nebula (Messier 27), captured here by Stellina using its default

settings in 102 frames over just 17 minutes.

The celebrated Double Cluster (NGC 884 and 869) in the constellation of Perseus captured by Stellina using its default settings in

just 77 frames over nearly 13 minutes.

In true minimalist style, the only external control for Stellina is a power button that glows blue when the instrument is
active. The telescope creates its own Wi-Fi hotspot and is controlled via Stellinapp on your smartphone or tablet.

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Futuristic astronomy: Vaonis Stel...

January 2021

Astronomy Now