Indie App Spotlight: Observatory puts the real sky on a Garmin dial

On 21 December the sun sets in London at 3:53 p.m., and civil twilight is over by 4:34 p.m. For anyone fitting in a late-afternoon run, those 41 minutes decide whether the run finishes in fading light or in the dark. Observatory, a new Garmin watch face, puts that light on the dial. The sun reaches the 3 at the wearer’s own sunset, the sky turns from gold to violet through their twilight, and after dark the dial becomes a map of the stars overhead.

Mihir Kadiya built Observatory for himself. After learning Garmin’s Connect IQ SDK, he wanted an analogue face he would enjoy looking at every time he raised his wrist, one that feels like a window rather than a dashboard. Partway through, he decided to share it, and it is now on the Connect IQ Store for 12 AMOLED watches.

A day on Observatory

TL;DR: The sun crosses the top half of the dial from the wearer’s real sunrise at the 9 to their real sunset at the 3. The dial’s colour and the length of the hands’ shadows follow the sun’s height, and after dusk the dial shows the stars and constellations overhead, with the moon keeping the hours below.

The dial is a clock and a sky at once. The sun rises at the 9 at the wearer’s sunrise, stands highest at the 12 and sets at the 3. At night the moon keeps the hours in the lower half, from the 3 at sunset round to the 9 at sunrise, drawn in that night’s phase. Three readings sit inside the dial.

In the morning the sun is low, so the hands cast long shadows away from it, two and a half times their length. As the sun climbs, the dial brightens and the shadows shorten to half the hands’ length at midday. Through the afternoon it runs in reverse until the sun reaches the 3 and the shadows go with it. After dark the dial shows the stars straight overhead, with up to three constellations drawn in fine lines and named, while the moon crosses below.

With the wrist down, the face falls back to a few grey lines. On a raise the sky returns at once, with the stars fading in at their places.

A December evening in London

On 21 December the sun in London never climbs higher than 15 degrees, so the hands’ shadows stay long all day. With one reading set to the next sunrise or sunset, the evening runs like this:

• 2:52 p.m. The sun drops below 6 degrees and golden hour starts. The rays nearest the sun turn gold, and the shadows lengthen towards two and a half times the hands.
• 3:43 p.m. Ten minutes before sunset, a short horizon line grows in at the 3, with a soft band of light along it.
• 3:53 p.m. The sun sinks behind the line, the shadows go with it, and the reading turns to the next sunrise, 8:04 a.m.
• Until 4:18 p.m. A fan of light shines up from under the horizon, gold, then orange, then rose, and the brightest stars come out.
• 4:18 to 4:34 p.m. In the blue hour the moon comes in at the 3, more stars appear, and the constellations are drawn and named.
• 4:34 p.m. Civil twilight ends, and the dial is the night sky until morning.

In New York the same evening starts at 3:48 p.m., the sun sets at 4:31 p.m. and night has fallen by 5:02 p.m.

How the sky is drawn

Everything is worked out on the watch for the wearer’s date and place, and the face makes no network calls of its own.

• The sun. Sunrise, sunset and the end of civil twilight, when the sun is 6 degrees below the horizon, come from the equations behind NOAA’s solar calculator. The location comes from Garmin’s weather or the last GPS activity.
• The stars. The face carries 290 stars from the Yale Bright Star Catalogue, each in its real colour, and the lines and names of 28 constellations, the Southern Cross among them. Once an hour the watch places about 56 stars for the wearer’s latitude and picks at most three constellations that stay clear of the hands and numerals. As in the real sky, the view at a given hour moves on month by month.
• The moon. Its phase is counted from a known new moon, in cycles of 29.53 days.

The hardest part was the colour. The watch screen has 16-bit colour, so a dusk gradient that looks smooth on a laptop breaks into visible rings on the wrist. Kadiya compared eight ways of drawing the same dusk side by side at three times zoom. The face now scatters the colour steps with a blue-noise pattern, evenly enough that the eye averages them away. The watch can’t blend two full-screen images, so each stage of twilight is prepared in advance and swapped in as the light changes.

Readings and settings

Each of the three slots, left, right and bottom, shows one of 16 readings: heart rate, stress, Body Battery, Pulse Ox, respiration, recovery time, steps, calories, intensity minutes, distance, move bar, battery, battery in days, next calendar event, next sunrise or sunset, and weather. Touching and holding a slot opens Garmin’s own screen for that reading. Everything is set in the face’s own menu on the watch.

The bed mark reads the sleep schedule set in Garmin Connect. In the three hours before bedtime, a small bed appears on the dial’s edge where the hour hand will be at bedtime, with a fine line from the hour hand to it. When the hand reaches the bed, it’s time to sleep.

The always-on page draws the dial in fine grey lines that light about 3% of the screen. It is redrawn once a minute and shifted slightly each time to protect the AMOLED display.

Quick answers

Does Observatory work without GPS or a phone nearby?
Yes. It uses the last location the watch knows, and everything is calculated on the watch. With no location at all, it assumes sunrise at 6:30 and sunset at 18:30.

Can I set it up from my phone?
Not yet. Every setting is in the face’s menu on the watch, and phone settings are planned.

My watch isn't listed. Is it next?
Owners of other models can ask for theirs, and those requests decide which watches come next.

Watches, battery and price

All 12 compatible watches are round AMOLED models with 390-pixel screens, and more are planned.

• Vivoactive: Vivoactive 5 and Vivoactive 6
• Venu: Venu 3S and Venu 4 41mm
• Forerunner: Forerunner 170, Forerunner 170 Music and Forerunner 570 42mm
• Epix: Epix Pro (Gen 2) 42mm
• Approach: Approach S70 42mm
• Descent: Descent Mk3 43mm
• MARQ: MARQ (Gen 2), including the Commander Carbon Edition, and MARQ (Gen 2) Aviator

On a Vivoactive 5 with always-on enabled, Observatory uses about the same battery as Garmin’s own analogue face, around 1% an hour.

Observatory is a one-off purchase of $4.99 through Garmin’s Connect IQ Store. There is no trial, but Garmin refunds a purchase within 48 hours. The most popular faces in the store are tracked every month in the Connect IQ charts.

The dial images are renders from Garmin’s Connect IQ simulator.

More information: Observatory on the Connect IQ Store and a video of a full day on the dial.

Author: Mihir Kadiya (Arka on the Connect IQ Store), developer of Observatory, edited by the5krunner.

If you enjoyed reading this, here is another in the Indie Spotlight series: Indie App Spotlight: OpenMaps puts a map under the route on a Garmin Instinct.

Last Updated on 10 November 2026 by tfk the5krunner

tfk the5krunner

tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. See the gear tfk uses. ID