Cambodia Beneath Dark Skies: Cardamom Mountains, Mekong Plains & Temple Landscapes
Stargazing in Cambodia changes sharply between the Cardamom rainforest, the open Mekong corridor and Khmer temple landscapes. The strongest artificial-light escape, the widest horizon and the most usable cultural foreground occur in different places, so the practical choice depends on what the night is meant to show. January–February is the Preferred Observing Window used for the seven-location portfolio because it falls inside the dry season and still provides about ten hours of astronomical darkness per night across these latitudes. “Dark skies” is descriptive here; no DarkSky International certification is implied.
Cambodia Night-Sky Planning Map
The markers represent approximate planning centers for the same seven locations used in the score. They are not guaranteed legal parking points, exact observing pull-offs or unrestricted night-access locations.
Cambodia Stargazing Suitability Score
This transparent editorial suitability index compares the seven selected locations through disclosed darkness, cloud, atmospheric, horizon, access and astronomy-support evidence. It is not an official sky classification, a live forecast or a guarantee of access.
The portfolio scores best on artificial-light escape, dry-season clear-sky reliability and astronomical darkness duration. The median access score is lower because protected wetlands, national parks and archaeological zones need local rule checks, while Preah Vihear is currently closed to tourism.
Method: Disclosed Editorial Rubric
Raw: Remote-rural, rural-regional-dome and settlement-influenced categories. No point SQM or VIIRS radiance value is claimed.
Location Values or Scores: Koh Pdao 85; Stung Treng Ramsar Site 85; Preah Vihear Temple 85; Kirirom National Park 70; Koh Ker 85; Chi Phat 85; West Baray 55.
Source Mapping or Rationale: Remote Cardamom, upper-Mekong and Koh Ker settings score above the Siem Reap-adjacent West Baray. Kirirom is rural but has more developed access and resort influence. NASA Black Marble is used only as nighttime-light context; no point extraction was performed.
Median: 85/100
Period: Landscape and access evidence reviewed 8 August 2026.
Sources: NASA Black Marble · Wildlife Alliance — Chi Phat · UNESCO — Koh Ker
Method: Disclosed Editorial Rubric
Raw: January–February dry-season category, adjusted only where local rainforest moisture raises interruption risk. No invented cloud-cover percentage is used.
Location Values or Scores: Koh Pdao 85; Stung Treng Ramsar Site 85; Preah Vihear Temple 85; Kirirom National Park 85; Koh Ker 85; Chi Phat 70; West Baray 85.
Source Mapping or Rationale: Cambodia’s dry season runs broadly November–April. Chi Phat is scored lower because the southwest Cardamom rainforest remains more exposed to local moisture and cloud than the drier interior and northern plain settings.
Median: 85/100
Period: Preferred Observing Window: January–February; climate references are long-term seasonal sources, not a live forecast.
Sources: World Bank — Cambodia Climate Risk Country Profile · UNFCCC — Cambodia Second National Communication
Method: Disclosed Editorial Rubric
Raw: Moisture, elevation and recurring haze exposure categories; this is planning transparency potential, not astronomical seeing.
Location Values or Scores: Koh Pdao 55; Stung Treng Ramsar Site 70; Preah Vihear Temple 70; Kirirom National Park 70; Koh Ker 70; Chi Phat 55; West Baray 55.
Source Mapping or Rationale: Low river and reservoir sites retain humid-air risk. Kirirom and Preah Vihear gain terrain height, while Chi Phat remains a low, humid rainforest environment. No total-column-water-vapour number is claimed.
Median: 70/100
Period: January–February seasonal planning context.
Sources: IUCN — Stung Treng Ramsar assessment · UNFCCC — Cambodia climate communication
Method: Full-window NOAA solar-position calculation
Raw: Mean nightly time with the Sun below −18° at each marker latitude: Koh Pdao 9.9728 h; Stung Treng Ramsar Site 10.0037 h; Preah Vihear Temple 10.0260 h; Kirirom National Park 9.9196 h; Koh Ker 10.0054 h; Chi Phat 9.9203 h; West Baray 9.9935 h.
Location Values or Scores: All seven locations normalize to 100 because each full-window mean is at least 9 hours.
Source Mapping or Rationale: Each marker latitude was evaluated night by night from 1 January through 28 February 2026 using the NOAA definition of astronomical twilight at solar elevation −18°.
Median: 100/100
Period: 1 January–28 February 2026 · 59/59 nights calculated for every location.
Sources: NOAA Solar Calculator Glossary
Method: Disclosed Editorial Rubric
Raw: Terrain height plus usable sky sectors, forest obstruction, reservoir or river openness and cliff geometry.
Location Values or Scores: Koh Pdao 85; Stung Treng Ramsar Site 70; Preah Vihear Temple 85; Kirirom National Park 70; Koh Ker 50; Chi Phat 50; West Baray 85.
Source Mapping or Rationale: Kirirom is mapped near 641 m but remains forested; Chi Phat’s immediate commune area averages near 7 m and is canopy-limited; Stung Treng Ramsar averages near 50 m with braided open channels; Koh Ker archaeological terrain is roughly 50–160 m and forested; West Baray is lowland but open; Preah Vihear occupies a cliff-top escarpment around 525 m.
Median: 70/100
Period: Terrain evidence current to source publication; mapped coordinates reviewed 8 August 2026.
Sources: IUCN — Stung Treng terrain · UNESCO — Preah Vihear map · UNESCO — Koh Ker map
Method: Disclosed Editorial Rubric
Raw: Booked community access, public-area clarity, protected-area uncertainty and current closure status.
Location Values or Scores: Koh Pdao 85; Stung Treng Ramsar Site 50; Preah Vihear Temple 0; Kirirom National Park 50; Koh Ker 25; Chi Phat 70; West Baray 50.
Source Mapping or Rationale: Koh Pdao and Chi Phat have community visitor systems that can support arranged overnight planning. Wetland, national-park and heritage markers require local rule checks. West Mebon has published daytime hours. Preah Vihear is currently closed to tourism under border-area restrictions.
Median: 50/100
Period: Access review: 8 August 2026. Access conditions can change faster than climate evidence.
Sources: APSARA — West Mebon hours · UK travel advice — Cambodia · NTFP-EP Cambodia — Koh Pdao
Method: Verified-support rubric
Raw: Current dark-sky designation, public astronomy facility or explicit night-light protection tied to the observing portfolio.
Location Values or Scores: Koh Pdao 0; Stung Treng Ramsar Site 0; Preah Vihear Temple 0; Kirirom National Park 0; Koh Ker 0; Chi Phat 0; West Baray 0.
Source Mapping or Rationale: Protected-area and World Heritage status are not treated as astronomy support. No current DarkSky International designation or public astronomy facility was verified for these seven planning locations during the review.
Median: 0/100
Period: Designation and facility check: 8 August 2026.
Weighted Total: 85×0.30 + 85×0.20 + 70×0.15 + 100×0.10 + 70×0.10 + 50×0.10 + 0×0.05 = 75.0 → 75/100
The country score is the weighted total of the seven factor medians across the same seven locations. Location count itself adds no bonus.
Read the Stargazing Suitability Score methodologyCambodia Stargazing Locations by Suitability Score
Scores compare planning suitability under the same January–February window. Search and filters do not change the ranking.
7 locations shown
Koh Pdao
Kratie · Mekong island
- Koh Pdao is a community-based ecotourism site on the Mekong in Kratie Province, with local visitor services supporting arranged stays.
- The planning marker uses the mapped community tourism office at 12.83002° N, 105.94507° E; it is a planning center rather than a guaranteed observing pull-off.
- A broad river corridor gives more usable low-altitude sky than a forest clearing, especially for meteor watching, moonrise and wide-field nightscape work.
- January–February sits inside Cambodia’s dry season, but low river elevation keeps humidity and near-horizon haze relevant.
Planning constraint: Best used through an arranged homestay or community stay. Confirm where outdoor lights can be avoided and which riverbank areas are appropriate after dark.
Stung Treng Ramsar Site
Stung Treng · Upper Mekong wetland
- Ramsar records the protected wetland at about 13°44′ N, 106°00′ E and 14,600 hectares along the Mekong north of Stung Treng.
- IUCN’s site assessment describes braided channels, islands, sandbars, rocky outcrops and flooded forest, with a mean elevation near 50 meters.
- Open-water sectors can provide long horizons, while islands, riparian vegetation and settlements make the usable sky geometry vary from one stopping point to another.
- The protected status is conservation evidence, not permission for unrestricted night access.
Planning constraint: Treat the marker as a wetland planning center. Boat use, protected-area rules, legal stopping points and the return route need to be settled before sunset.
Preah Vihear Temple
Dangrek Mountains · Border cliff
- UNESCO’s mapped World Heritage coordinates place the temple at 14.390841° N, 104.680325° E on the Dangrek escarpment.
- The cliff-top setting gives an exceptional southern horizon over the Cambodian plain in geographic terms.
- Current travel advice reviewed on 8 August 2026 lists Preah Vihear among border tourist destinations that are closed and warns of unexploded ordnance in the border area.
- The location remains in the portfolio because it shows how strong sky geometry can be overridden by access and safety.
Planning constraint: Do not plan an observing visit to the temple while the closure remains in force. The Access score is 0, and no route around a closure or security control is suggested.
Kirirom National Park
Kampong Speu · Eastern Cardamom plateau
- Kirirom occupies an elevated eastern Cardamom setting; mapped terrain near the park center is about 641 meters above sea level.
- The elevation helps separate it from Cambodia’s low plains, yet pine forest and ridges mean a high site does not automatically provide a 360-degree horizon.
- Its road connection makes it easier to reach than interior Cardamom locations, which also means more local lighting pressure around developed areas.
- January–February is the stronger seasonal planning window, with dry-season access generally more practical than during monsoon conditions.
Planning constraint: Night gate, parking and stopping rules were not found in a form strong enough to treat independent after-dark access as assured. Confirm current park arrangements before relying on a viewpoint.
Koh Ker
Preah Vihear Province · Remote temple forest
- UNESCO maps the World Heritage property at 13°46′59″ N, 104°32′14″ E, well away from the main Siem Reap urban light source.
- Published archaeological landscape work places much of the Koh Ker study area between roughly 50 and 160 meters elevation.
- The forested archaeological landscape can be locally dark while trees and structures limit the horizon from many ground-level positions.
- Its value for nightscape planning is the combination of rural darkness and Khmer landscape context, not an assumption that the monument zone stays open at night.
Planning constraint: No unrestricted independent night access to the archaeological property is assumed. Use only lawful exterior or separately authorized locations and verify current site rules.
Chi Phat
Koh Kong · Cardamom rainforest
- Chi Phat’s community tourism project sits in the Cardamom landscape of Koh Kong, surrounded by rainforest and river routes.
- The planning coordinate at 11.3290° N, 103.5225° E represents the commune center; topographic mapping gives the immediate lowland area an average elevation near 7 meters.
- Remoteness supports strong artificial-light escape, but canopy and local relief can hide much of the low sky unless an open riverbank, field or authorized clearing is used.
- The southwest rainforest setting keeps moisture, cloud remnants and haze relevant even inside the dry season.
Planning constraint: A very dark-feeling forest is not automatically a broad astronomical horizon. Arrange overnight activity through the community and choose the observing area in daylight.
West Baray
Angkor · Siem Reap reservoir landscape
- West Baray is a long east–west reservoir immediately west of Angkor Thom, giving a much wider horizon than most forested temple compounds.
- The planning marker at 13.4342° N, 103.8006° E is central to the reservoir landscape, not a parking instruction.
- Siem Reap’s nearby urban lighting reduces artificial-light escape compared with Koh Ker, Chi Phat or the upper Mekong.
- APSARA lists West Mebon visitor hours as 7:30 a.m. to 5:30 p.m.; that day-use schedule is a clear warning against assuming nighttime temple access.
Planning constraint: Use lawful public areas only and confirm after-dark rules locally. A visible temple or reservoir does not create permission to enter closed heritage areas with a tripod.
Cardamom Darkness Is Often Overhead, Not Horizon-Wide
Chi Phat: low light, low elevation, dense edges
Chi Phat earns 85 for Artificial-Light Escape because its Cardamom setting is far from Cambodia’s main urban light sources. The practical sky can still feel smaller than the darkness suggests. Rainforest canopy, riverbank vegetation and low relief can block the first 20–30 degrees of sky in several directions, so a clearing chosen in daylight matters more than a small change in map coordinates.
Its lowland setting also keeps moisture in the decision. A cloud-free forecast can still produce soft contrast near the horizon when humid air or thin haze is present.
Kirirom: elevation without a guaranteed open dome
Kirirom moves the observer to roughly 600-plus-meter terrain and away from the low Mekong plain. That improves terrain position and can help atmospheric transparency, yet the park remains forested and developed pockets introduce local lights. Open viewpoints are more useful for wide-field observing than simply choosing the highest road segment.
The Cardamom comparison is therefore geometric as well as photometric: Chi Phat offers stronger remoteness, while Kirirom offers height and easier road access.
Darkness and transparency are separate conditions. A remote rainforest can have little artificial light while humidity, thin cloud or canopy still limits faint-star contrast and horizon coverage.
The Mekong Trades Mountain Height for Sky Geometry
Koh Pdao and the Stung Treng Ramsar Site are low-elevation choices, yet both can expose more continuous sky than a Cardamom forest. The useful asset is the river corridor: long water surfaces, sandbars and open channels reduce foreground obstruction and make meteor tracks, moonrise and low-altitude bright objects easier to follow.
Koh Pdao for an arranged river night
Koh Pdao leads the portfolio at 78/100 because its 85-point light-escape score is paired with an 85-point horizon score and the clearest access pattern among the seven locations. Community tourism and homestay infrastructure create a practical way to be present after sunset without treating an unknown roadside pull-off as an observing site.
Village lamps and river humidity remain local constraints. Moving a short distance from a bright lamp can matter more than moving several kilometers along an otherwise similar riverbank.
Stung Treng for a broader wetland horizon
The Ramsar corridor contains braided channels, islands, rocky outcrops and flooded forest rather than one continuous open bank. That creates strong wide-sky sectors, but the exact horizon depends on the channel and season. The protected wetland also needs more access planning than Koh Pdao.
River reflections can be useful for moonlit nightscapes. They do not improve faint-sky visibility, and a bright Moon can wash out the same Milky Way structure a dark river foreground is meant to frame.
Temple Foregrounds Do Not Create Night Access
Cambodia’s temple landscapes are powerful foregrounds, but visitor rules control whether they can be used after sunset. The map treats West Baray, Koh Ker and Preah Vihear as planning landscapes, not as permission to enter monuments or protected compounds at night.
West Baray: open water beside a city light dome
The reservoir supplies an unusually long horizon inside the Angkor landscape, while nearby Siem Reap lowers the light-escape score to 55. APSARA lists West Mebon visitor hours as 7:30 a.m.–5:30 p.m. A night photograph from a lawful public edge cannot be treated as permission to enter West Mebon or another closed monument.
Koh Ker: rural darkness, forest-limited sightlines
Koh Ker is much farther from Siem Reap’s urban glow and receives 85 for light escape. Forest and archaeological structures narrow many ground-level horizons, and unrestricted independent night access to the World Heritage property is not assumed. The useful planning question is where a lawful exterior location can retain the rural sky without crossing a protected boundary.
Preah Vihear: strong horizon, current closure
Preah Vihear has the strongest cliff geometry in the temple group and a remote night-sky setting. Its Access score is 0. Travel advice reviewed on 8 August 2026 lists the temple among closed border destinations and warns of unexploded ordnance in the border area. No stargazing visit should be planned there while that closure remains in force.
Khmer Orientation: Use the Evidence, Not a Constellation Story
Archaeoastronomical research on the Khmer heartland has found a recurring pattern of cardinal orientation and alignment across temples, reservoirs and topography. That is a stronger basis for discussing sky relationships than claims that every temple reproduces a constellation or encodes a hidden star map.
Koh Ker is especially useful because its state-temple orientation differs from the more common cardinal pattern. Research by Giulio Magli has proposed a relationship between Koh Ker’s anomalous orientation and the Sun’s zenith passage; related work discusses a lunar-standstill interpretation for Preah Khan of Kompong Svay. These are research interpretations of specific alignments, not a license to assign an astronomical meaning to every visual alignment photographed today.
January–February Reduces Monsoon Risk; the Moon Still Sets the Faint-Sky Limit
Cambodia’s national climate sources describe a dry season broadly from November through April, with the wetter monsoon season occupying much of May through October. January–February is used here because it gives all seven locations the same dry-season comparison window and every marker averages more than 9.9 hours of full astronomical darkness across the 59-night calculation.
For faint Milky Way structure
Prefer nights when the Moon is absent from the main observing hours. The location score does not include lunar phase, so a 78/100 site under a bright Moon can show less faint structure than a lower-scored site on a dark lunar window.
For temple and landscape balance
A thin crescent can leave enough darkness for stars while giving a small amount of natural foreground light. This is often more useful for a reservoir, cliff or temple-edge composition than insisting on a completely moonless foreground.
For moonrise over water
A bright Moon is poor for faint-sky contrast but can be chosen deliberately for Mekong reflections or moonrise geometry. It changes the target rather than the underlying access, horizon or climate score.
How the Seven Cambodia Locations Differ
The table keeps the same score-sorted order as the map and location cards.
| Location | Score | Light Escape | Clear Sky | Best Use | Horizon | Night Access | Main Constraint |
|---|---|---|---|---|---|---|---|
| Koh Pdao | 78/100 | 85 | 85 | Meteor fields, moonrise, river nightscapes | Broad river sectors | Arrange through community stay | Humidity and local village lights |
| Stung Treng Ramsar Site | 75/100 | 85 | 85 | Wide-field sky, upper-Mekong horizons | Variable open channels | Protected-area check needed | Protected wetland logistics |
| Preah Vihear Temple | 72/100 | 85 | 85 | Geographic context only while closed | Cliff-wide southern view | Closed to tourism | Current closure and border hazards |
| Kirirom National Park | 71/100 | 70 | 85 | Elevated landscape, wide-field photography | Plateau with forest breaks | Night rules need confirmation | Trees, gates and developed-area lighting |
| Koh Ker | 71/100 | 85 | 85 | Remote temple-landscape photography | Forest-limited | Night access not assumed | Forest horizon and heritage access |
| Chi Phat | 70/100 | 85 | 70 | Dark-adapted forest and river-clearance sky | Canopy-limited | Arrange through CBET | Canopy, moisture and route planning |
| West Baray | 65/100 | 55 | 85 | Reservoir horizon and controlled nightscape work | Long reservoir horizon | Heritage rules and hours apply | Siem Reap light dome and heritage access |
Tonight’s Astronomical Darkness
Calculated live from each location’s coordinates using NOAA’s public solar-position formula. Weather, cloud cover and local obstructions are not included.
Calculating…
Data Verification and Limits
Principal data periods: dry-season climatology from long-term Cambodia climate references; heritage and access sources checked through 8 August 2026; protected-area geography from current Ramsar, UNESCO, APSARA, conservation and community-tourism material; astronomical darkness calculated for the 2026 review season.
Limitations: Artificial-Light Escape uses a disclosed categorical rubric because no point SQM measurement or extracted VIIRS radiance series was available for all seven locations. Clear-sky and atmospheric scores use seasonal categorical evidence rather than fabricated local percentages. Marker coordinates are planning centers. Local lamps, cloud, smoke, river mist, road conditions, gates and protected-area rules can change the actual observing night.