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Cerro Calan OAN

Chile Chile astronomical observatory

National Astronomical Observatory

An astronomical observatory in Chile, and the real sky above it tonight.

Calculating the sky…

Drag to turn round. Stars from the HYG catalogue; glow and horizon from the light model and the terrain.

The place

National Astronomical Observatory.

Observatory in Chile

National Astronomical Observatory is an astronomical observatory in Chile, 860 m above the sea.

Its usual sky, with no Moon or clouds, is estimated at 17.90 mag/arcsec² — Bortle 8, city sky: the naked eye reaches stars of magnitude 3.9.

The nearest town of over 50,000 people is 7 km away.

The best months are from February to March: long dark nights and clearer skies.

The core of the Milky Way rises up to 86° above the horizon, and is up during the dark hours from February to October.

The relief hides 7% of the sky; the highest point of the horizon is 11° up, to the east.

Cerro Calan OAN
Tomás J. Sepúlveda · CC BY 2.0

Visit and sleep under the stars

  • Visiting the observatoryMany observatories open for guided nights or open days: check the official site.
  • área de campamento Valle Suizocampsite · 7.9 km · 5 within 10 km
  • Hotel Acacias de Vitacuraplace to stay · 1.9 km · 221 within 10 km
  • Ñuñoanearest town · 7.1 km in a straight line
  • Comodoro Arturo Merino Benítez International Airport (SCL)nearest airport with scheduled flights · 23 km in a straight lineCar hire at SCL airport (Santiago)Discover Cars · sponsored link

Plan the night

A guided night, a bed nearby, a car.

Some links above are affiliate links: if you book through them we may earn a commission, at no extra cost to you. It never changes what the data on this page says.

The usual sky here

Bortle 8.

The sky is orange or white; you can read by it; only the brightest stars show.

32out of 100

Our own rating, from verifiable data only: sky brightness (60 points), clear nights (25), open horizon (10) and altitude (5).

  1. 1Excellent dark sky≥ 21.89 · stars to mag 7.6
  2. 2Truly dark sky21.69–21.89 · stars to mag 7.1
  3. 3Rural sky21.25–21.69 · stars to mag 6.6
  4. 4Rural–suburban transition20.49–21.25 · stars to mag 6.1
  5. 5Suburban sky19.50–20.49 · stars to mag 5.6
  6. 6Bright suburban sky18.94–19.50 · stars to mag 5.1
  7. 7Suburban–urban transition18.38–18.94 · stars to mag 4.6
  8. 8City sky17.80–18.38 · stars to mag 4.1 You are here
  9. 9Inner-city sky< 17.80 · stars to mag 3.6
  • 17.90Sky brightnessmag/arcsec² at the zenith — 21.9 is a natural sky
  • 3.9Faintest starthe faintest magnitude the naked eye can see here
  • 7 kmNearest big townover 50,000 people, in a straight line
  • 860 mAltitudeabove the sea: less air and haze above you
  • 93%Open skyof the half-sphere the relief leaves visible

Where the light comes from

The brightest glow on the horizon comes from Santiago, 12 km to the south-west.

Each wedge is how much artificial light arrives from that direction (10° slices).

NESWSantiago 12 kmÑuñoa 7 kmPeñalolén 8 kmPuente Alto 24 km

An estimate of the usual sky with no Moon and no clouds, from NASA's night-lights map and a light-propagation model (about ±0.3 mag). A given night depends on the Moon, the clouds, dust and humidity.

When to go

Best from February to March.

Hours of truly dark night, hours with the core of the Milky Way up, how often the sky is clear and the coldest night, month by month.

  1. 6.5h68%16°Jan
  2. 7.7h69%16°Feb
  3. 8.8h64%14°Mar
  4. 9.8h48%11°Apr
  5. 11h30%8°May
  6. 11h26%5°Jun
  7. 11h26%4°Jul
  8. 10h28%5°Aug
  9. 9.3h32%7°Sep
  10. 8.3h36%9°Oct
  11. 7.0h52%12°Nov
  12. 6.3h63%14°Dec
  • Dark night (hours)
  • Milky Way core up
  • Clear sky
  • Coldest night
  • Best months

The Moon, night by night

A bright Moon washes out the faint stars. The highlighted nights are the dark ones (less than a quarter lit); below, the next new moons.

  • 9 Nov2026
  • 9 Dec2026
  • 7 Jan2027
  • 6 Feb2027
  • 8 Mar2027
  • 6 Apr2027

Night: Sun more than 18° below the horizon. Milky Way: the galactic centre more than 10° up during that night. Clear sky: 100 − NASA cloud amount (2001–2020). Coldest: average minimum brought to this altitude.

What happens in this sky

Meteors, eclipses, auroras.

Meteor showers

The next twelve months. The rate is what a dark sky shows with the radiant at its highest here; the Moon decides the rest.

  • Orionidspeak 21 Oct 2026 · up to 13 meteors an hourMoon 74% lit at the peak
  • Leonidspeak 17 Nov 2026 · up to 9 meteors an hourMoon 48% lit at the peak
  • Geminidspeak 14 Dec 2026 · up to 60 meteors an hourMoon 23% lit at the peak
  • Lyridspeak 22 Apr 2027 · up to 7 meteors an hourMoon 98% lit at the peak
  • Eta Aquariidspeak 6 May 2027 · up to 42 meteors an hourMoon 0% lit at the peak
  • Southern Delta Aquariidspeak 30 Jul 2027 · up to 24 meteors an hourMoon 14% lit at the peak

Eclipses

Lunar eclipses visible from here, and solar eclipses whose path crosses this country.

  • Partial lunar eclipse12 january 2028Moon 33° up at mid-eclipse · 53 min
  • Total lunar eclipse26 june 2029Moon 70° up at mid-eclipse · 101 min
  • Annular solar eclipse6 february 2027the path crosses this country — check the exact line before you go

Meteor dates: International Meteor Organization peaks. Lunar eclipses: computed (J. Meeus) and shown only when the Moon is above this horizon. Solar eclipses: Eclipse Predictions by Fred Espenak, NASA/GSFC (country on the path).

The horizon

360° around you.

The silhouette of the relief up to 30 km away (Copernicus DEM), with the light domes of the towns where they rise. Mountains are drawn taller than they are, to be seen.

NNEESESSWWNWSantiago · 12 kmÑuñoa · 7 kmPeñalolén · 8 kmPuente Alto · 24 km
NNEESESPeñalolén · 8 kmSSWWNWSantiago · 12 kmÑuñoa · 7 kmPuente Alto · 24 km
National Astronomical Observatory seen from above (Sentinel-2)
Seen from above: Sentinel-2 cloudless 2016 (EOX, CC BY 4.0), 6 × 6 km, north up. Points © OpenStreetMap contributors.

Around, in OpenStreetMap

  • 10observatories and planetariums within 30 kmMirador Copernicus, Observatorio UC, Planetario and 7 more
  • 26viewpoints within 5 kmPiedra Rajada, Mirador Altas Cumbres, Mirador de la Roca and 23 more
  • 11named peaks within 5 kmCerro Calán, Cerro Alvarado, Cerro Apoquindo and 8 more
  • 2marked trails within 3 kmSendero a Salto de Apoquindo, Sendero Bulnes Correa-Morro Las Papas
  • 4shelters and huts within 5 km
  • 152car parks within 3 km
  • 5campsites within 10 kmárea de campamento Valle Suizo, Camping Vallecito, Baños de la Cal and 2 more
  • 221places to stay within 10 kmHotel Acacias de Vitacura, Best Western Premier Marina, Hotel Park Inn and 218 more
  • 6visitor centres within 5 kmOficina Central Parque Cordillera, Administración Parque Cordillera San Carlos de Apoquindo, Punto de Información Ambiental and 3 more
  • 537restaurants and cafés within 5 km
  • street lamps mapped within 2 km

Counted in OpenStreetMap, the map anyone can edit. A low number may just mean nobody has mapped it yet.

In our other atlases

Around it, by day.

The mountain, island, lake, beach or canyon this place is, and what else is nearby in the family's atlases.

Peakyas70 mountains within 25 km
Cerro Alvarado1,022 m · 2.9 kmCerro del Medio1,011 m · 5.5 kmCerro San Cristóbal880 m · 9.5 kmCerro Provincia2,750 m · 10 kmSanta Lucía Hill · 11 kmCerro Renca · 16 kmCerro Navia515 m · 17 kmCerro La Ballena877 m · 23 km
Cascadyas1 waterfalls within 15 km
Apoquindo Waterfall · 8.7 km

Figures from the sister sites' databases (Wikidata, HydroATLAS, GeoNames, OpenStreetMap). Links open when each site is online.

Photographs

By day and by night.

Heritages Day 2022 at Cerro Calán National Observatory in Chile (IMG 9258-CC)
NOIRLab/NSF/AURA · CC BY 4.0
Heritages Day 2022 at Cerro Calán National Observatory in Chile (IMG 9264-CC)
NOIRLab/NSF/AURA · CC BY 4.0
Mirador Manquehue del Parque Observatorio Cerro Calán
TomasVial · CC BY-SA 4.0

Other skies nearby.

National Astronomical Observatory

Chile

  • 32Darkskyas Score
  • 17.90Sky brightness
  • 8Bortle
  • 860 mAltitude

Tupungato Volcano

Argentina · 71 km

  • 86Darkskyas Score
  • 21.85Sky brightness
  • 2Bortle
  • 6,635 mAltitude

See the guide

Aconcagua

Argentina · 96 km

  • 90Darkskyas Score
  • 21.87Sky brightness
  • 2Bortle
  • 6,962 mAltitude

See the guide

Volcán Maipo

Chile · 107 km

  • 86Darkskyas Score
  • 21.86Sky brightness
  • 2Bortle
  • 5,264 mAltitude

See the guide

Where these figures come from

Name, type, certificationWikidata (Q5811531) · CC0
Sky brightnessNASA Earth Observatory, Black Marble 2016 (Suomi NPP VIIRS) · Darkskyas light model (Walker's law, fitted to 18 measured sites)
Night, Moon, Milky Way, starsJ. Meeus, Astronomical Algorithms · HYG v4.4 · Stellarium modern_iau (CC BY-SA 4.0)
Horizon and altitudeCopernicus DEM GLO-90 / GLO-30 · © DLR e.V., © Airbus Defence and Space GmbH, Copernicus/ESA
Clouds and temperatureNASA POWER (CERES SYN1deg, 2001–2020; MERRA-2)
Solar eclipsesEclipse Predictions by Fred Espenak, NASA/GSFC
What is around© OpenStreetMap contributors · ODbL
ImagesEOX Sentinel-2 cloudless 2016 · CC BY 4.0; Wikimedia Commons
Sister atlasesPeakyas, Cascadyas

Every figure is an average, an estimate or a count from a public dataset. Licences and methods: data sources.

The family

Do you prefer beaches, lakes, mountains, waterfalls, islands, rivers, canyons, caves, dark skies, viewpoints, birdwatching or forests?

Same idea, other landscapes: field atlases built on open data, in seven languages.

beachesCoastyaFind your beach: sea temperature, sun and swimming month by month.Visit lakesLakeyasEvery lake on Earth: water temperature, ice, depth and the shore.Visit mountainsPeakyasEvery summit in 3D: summit weather, the 0 °C line, huts and trails.Visit waterfallsCascadyasEvery waterfall: height, flow month by month and when it roars.Visit islandsIslandyasEvery island from the sea up: size, sea temperature, ferries and 3D.Visit riversRiveryasEvery river from source to sea: the journey, the flow and the basin in numbers.Visit canyonsCanyonyasEvery canyon cut to scale: depth to the floor, rim and floor temperatures, trails and viewpoints.Visit cavesCavernyasEvery cave with its real depth and length: the rock above, the temperature inside all year, and how to visit.Visit
dark skiesDarkskyasWhere the night is still dark: the sky of every place, the Milky Way month by month, the Moon, eclipses and auroras.You are here
viewpointsViewyasEvery viewpoint with its real 360° panorama: the peaks you can name, how far you see and where the sun sets.Coming soonVisit
birdwatchingBirdyasEvery bird sanctuary and wetland with the species recorded month by month: who is resident, who comes for the summer, who only passes through.Coming soonVisit
forestsForestyaEvery forest with its land-cover rings, what grows and lives in it, and the best months to walk it.Coming soonVisit