Onyx Cave is a cave in Phelps County, Missouri. It sits roughly 13.1 km (8.1 mi) SSE of Dixon. It is listed on the National Register of Historic Places.
Onyx Cave, also known as King Cave and Boiling Springs Cave, is a historic natural cave located near Newburg, Pulaski County, Missouri. The cave consists of the main room measuring approximately 85 feet wide, 250 feet long, and 33 feet high, and two passageways. The cave features translucent cave onyx that is pure white to cream in color, some with reddish-colored banding. Formations range from the common stalactites, stalagmites, and columns, to beautiful draperies. An 8 foot by 13 foot vertical shaft was sunk in 1892 to mine the onyx. It was listed on the National Register of Historic Places in 1999.From the Wikipedia article “Onyx Cave (Newburg, Missouri)”, licensed under CC BY-SA 4.0.
Sunrise & sunset directions
At Onyx Cave the sunrise point swings a long way through the year: about 59° (ENE) at the June solstice and 120° (ESE) in late December. Sunset moves from 301° (WNW) in June to 241° (WSW) in December, and the midday sun climbs to 76° in summer but only 29° in winter.
| Date | Sunrise | Azimuth | Sunset | Azimuth | Noon sun | Daylight |
|---|---|---|---|---|---|---|
| March equinox (Mar 20) | 7:13 AM | 90° E | 7:20 PM | 271° W | 52° | 12h 08m |
| June solstice (Jun 21) | 5:47 AM | 59° ENE | 8:34 PM | 301° WNW | 76° | 14h 48m |
| September equinox (Sep 22) | 6:57 AM | 89° E | 7:07 PM | 271° W | 52° | 12h 10m |
| December solstice (Dec 21) | 7:21 AM | 120° ESE | 4:53 PM | 241° WSW | 29° | 9h 32m |
Azimuth is measured clockwise from true north (90° = east, 270° = west). Computed for 2026; values change by less than a degree from year to year.
Golden hour & blue hour by month
Caves are lit artificially — show caves have fixed lighting, so a fast lens and high ISO beat flash, which flattens formations.
| Month (15th) | Blue hour starts | Sunrise | Golden hour ends | Golden hour starts | Sunset | Blue hour ends | Daylight |
|---|---|---|---|---|---|---|---|
| January | 6:55 AM | 7:23 AM | 8:03 AM | 4:33 PM | 5:13 PM | 5:42 PM | 9h 50m |
| February | 6:32 AM | 6:59 AM | 7:35 AM | 5:11 PM | 5:47 PM | 6:14 PM | 10h 48m |
| March | 6:54 AM | 7:20 AM | 7:55 AM | 6:41 PM | 7:16 PM | 7:42 PM | 11h 55m |
| April | 6:06 AM | 6:33 AM | 7:09 AM | 7:09 PM | 7:44 PM | 8:11 PM | 13h 10m |
| May | 5:29 AM | 5:59 AM | 6:36 AM | 7:34 PM | 8:12 PM | 8:41 PM | 14h 13m |
| June | 5:15 AM | 5:46 AM | 6:25 AM | 7:54 PM | 8:33 PM | 9:04 PM | 14h 47m |
| July | 5:28 AM | 5:58 AM | 6:37 AM | 7:52 PM | 8:31 PM | 9:01 PM | 14h 32m |
| August | 5:56 AM | 6:24 AM | 7:00 AM | 7:27 PM | 8:03 PM | 8:31 PM | 13h 39m |
| September | 6:24 AM | 6:51 AM | 7:25 AM | 6:43 PM | 7:18 PM | 7:44 PM | 12h 27m |
| October | 6:51 AM | 7:17 AM | 7:53 AM | 5:56 PM | 6:32 PM | 6:58 PM | 11h 15m |
| November | 6:21 AM | 6:49 AM | 7:28 AM | 4:19 PM | 4:58 PM | 5:26 PM | 10h 08m |
| December | 6:48 AM | 7:17 AM | 7:59 AM | 4:10 PM | 4:51 PM | 5:20 PM | 9h 33m |
Local time (America/Chicago), including daylight saving time. Golden hour runs from about −4° to +6° solar altitude, so the morning golden hour begins during blue hour, before sunrise.
Milky Way & night sky
From Onyx Cave, the Milky Way core is visible in a dark sky from March through September. June gives the longest window (about 5.3 hours on a moonless night), and the core peaks around 23° above the southern horizon. Our light-pollution model puts the sky at about Bortle 3 (rural sky), good enough for detailed Milky Way images.
| Month | Core visible (15th) | Hours | Max altitude | Direction |
|---|---|---|---|---|
| January | Below 10° in darkness | — | -1° | — |
| February | 5:05 AM – 5:25 AM | 0.3 | 13° | SE → SE |
| March | 4:13 AM – 5:43 AM | 1.5 | 19° | SE → SSE |
| April | 2:17 AM – 4:57 AM | 2.7 | 23° | SE → S |
| May | 12:17 AM – 4:07 AM | 3.8 | 23° | SE → S |
| June | 10:28 PM – 3:48 AM | 5.3 | 23° | SE → SW |
| July | 10:22 PM – 2:22 AM | 4.0 | 23° | SSE → SW |
| August | 9:41 PM – 12:21 AM | 2.7 | 23° | S → SW |
| September | 8:47 PM – 10:17 PM | 1.5 | 20° | SSW → SW |
| October | 7:59 PM – 8:19 PM | 0.3 | 13° | SW → SW |
| November | Below 10° in darkness | — | 1° | — |
| December | Below 10° in darkness | — | -19° | — |
Window when the galactic core is at least 10° high during astronomical darkness on the 15th of each month. Pick nights within a few days of the new moon. Plan exact nights with the Milky Way planner.
Estimated sky darkness: 3 Bortle 3 — Rural sky. Some light domes sit on the horizon, but the Milky Way still looks complex overhead. Modeled zenith brightness ≈ 21.61 mag/arcsec². Aurora needs roughly Kp 8.0+ to show low on the northern horizon here.
Weather & best season
Long-term NASA satellite data for this area show September as the clearest month (about 42% average cloud cover) and February as the cloudiest (64%). July is the warmest month and January the coldest, which matters for gear, snow access and how long batteries last at night.
Average cloud cover (%)
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| High °F | 72 | 74 | 82 | 86 | 98 | 106 | 107 | 108 | 99 | 92 | 82 | 71 |
| Low °F | -6 | -5 | 1 | 20 | 29 | 45 | 53 | 48 | 38 | 24 | 8 | -8 |
| Precip. (in) | 2.5 | 3.0 | 4.2 | 5.3 | 5.6 | 4.4 | 4.4 | 4.5 | 3.8 | 3.9 | 3.6 | 2.8 |
Monthly climatology for the surrounding 1° grid cell from NASA POWER (MERRA-2). Mountain sites can be colder and cloudier than the cell average.
Photography tips for this cave
- Never touch formations — skin oils stop their growth.
- Follow White-nose Syndrome decontamination rules where posted to protect bats.
- Many show caves restrict tripods on tours; ask in advance or bring a small beanbag.
- Use manual focus with focus peaking in low light.
- Bring a spare battery — cold weather and long exposures drain them fast.
Season: Cave interiors stay at a constant temperature year-round; summer tours fill up, so book ahead.
Suggested gear: Fast lens (f/1.8–f/2.8), High-ISO camera, Small beanbag. Work out exposures with the depth of field, ND filter and NPF rule calculators.
Nearby photo spots
Other locations within 25 km of Onyx Cave, closest first.
Natural Arch
Ghost TownNatural ArchGhost TownCampgrounds nearby (Recreation.gov)
FAQ
When is the best time to photograph Onyx Cave?
What time is golden hour at Onyx Cave?
Where does the sun rise and set at Onyx Cave?
Can you see the Milky Way from Onyx Cave?
Do you need a permit to photograph at Onyx Cave?
How far is Onyx Cave from Dixon?
Sources
Location data: Wikidata, Wikipedia. Sun, moon and Milky Way times are computed by LWPhoto Atlas for 2026. Climate: NASA POWER. Sky darkness is a population-based estimate (Walker's law), not a measurement. See data sources & licenses.