The moon goes through regular phases during each lunar cycle, changing in appearance from new moon to full moon and back to new moon again over the course of about 29.5 days. The different phases occur because from our perspective on Earth, we can only see the portion of the moon’s surface that is illuminated by the sun. As the moon orbits around the Earth, different amounts of the lunar surface are lit up by the sun. This results in the changing phases we observe from night to night.
Phases of the Moon
During the new moon phase, the moon is positioned between the Earth and the sun, so that the side facing the Earth is not illuminated at all. At this point the moon is nearly invisible to us, except for a faint outline lit by sunlight reflected from the Earth. As the moon moves around in its orbit, increasing amounts of the side facing Earth become illuminated by the sun. A few days after new moon, a thin crescent moon appears in the western sky after sunset. The crescent grows fatter each night, called the waxing phase. After about one week, half of the moon’s face appears illuminated – this is the first quarter phase. Over the next week, more than half of the moon becomes brightened by sunlight, culminating in the full moon phase when the entire side facing Earth is lit up. After full moon, the cycle reverses through the waning phases: the illuminated area shrinks night by night through the third quarter and back to the thin crescent. Finally, new moon occurs again and the lunar cycle repeats.
Why Does the Moon Appear Orange Sometimes?
While the moon goes through regular phases, its appearance can vary slightly from one night to the next. Sometimes the moon may take on an orange or reddish hue instead of its usual pale color. There are a few possible reasons why this happens:
- Position near the horizon – When the moon is low on the horizon, its light must travel through more of the Earth’s atmosphere before reaching our eyes. The atmosphere scatters shorter wavelength blue light, allowing more long wavelength red light to pass through. This gives the moon a yellow or orange tint.
- Dust or smoke particles – Particles in the atmosphere from dust storms, wildfire smoke or volcanic eruptions do the same thing, scattering blue light and letting more red light through. This can make the moon appear reddish or orange.
- Clouds – Thin or patchy clouds can also preferentially scatter blue light relative to red, especially if the moon is near the horizon.
- Lunar eclipses – During a total lunar eclipse, the moon takes on a reddish color as it passes into the Earth’s shadow. Some sunlight reaching the moon is refracted by the Earth’s atmosphere, giving the eclipsed moon a deep red glow.
Tonight’s Moon
Tonight, on September 5, 2023, the moon is in a waxing gibbous phase, meaning more than half but not yet all of the side facing Earth is illuminated. The moon rose in the east just after sunset and will be high overhead during most of the night. As of 9 PM, the moon appears about 80% illuminated and is starting to take on an orange tint as it climbs higher into the sky. The orange color is likely caused by the moon’s current position – being viewed through a greater thickness of Earth’s atmosphere near the horizon. As the moon reaches its peak height later tonight, around 2 AM, it may have more of its usual white or pale gray appearance. But throughout the evening, the prominent orange cast gives us a great opportunity to observe and photograph this sometimes fleeting coloration of the moon.
When to See an Orange Moon
An orange moon can happen during any phase, but a full or mostly full moon often appears more colorful because the entire disk is illuminated. A bright orange moon is most likely to occur just after moonrise or just before moonset, rather than high overhead. It also helps if there are dust, smoke or thin clouds in the sky to accentuate the effect. Some of the best sightings happen during prominent events like forest fire seasons or following major volcanic eruptions that inject large amounts of particles high into the atmosphere.
The time of year also makes a difference. In northern latitudes, the angle of the setting sun during autumn can enhance atmospheric scattering and give a rich orange tone to the rising harvest moon. Cold, dry winter air also tends to create optimal scattering conditions for an orange moon near the horizon. So the seasons of fall and winter present more opportunities for spotting an eye-catching orange lunar display.
When to Photograph an Orange Moon
For photographers, a brightly colored moon rising or setting on the horizon makes a great subject. The ideal time to capture these images is when the moon is close to trees, buildings or other landscape features that provide an interesting silhouette or framing element. To get the true color of an orange moon, use exposure and white balance settings that avoid blowing out the image or making the moon appear brighter or whiter than it really looks. The following tips can help:
- Use a low ISO sensitivity setting to minimize noise in silhouetted foreground elements
- Stop down the aperture to f/8 or higher for a sharper, clearer image
- Set white balance to Daylight or Kelvin ~5500K to preserve the orange tone
- Shoot in RAW format for more control over color temperature in post-processing
- Take a series of shots as the moon rises or sets to capture the best moment
Planning your moon photography around forest fire seasons, volcanic activity, around the autumn harvest moon or during clear and cold winter nights will give you the best chance to capture a dramatic orange moon. With the right settings and timing, you can achieve amazing images of this visually stunning lunar phenomenon.
Is an Orange Moon Rare?
While certain conditions make an orange moon more likely, it is not an especially rare event. These lunar colors can be observed multiple times a year, more frequently during certain seasonal windows. Here are some estimated frequencies for seeing an orange moon under favorable conditions:
| Time of Year | Frequency |
|---|---|
| Harvest moon in fall | 3-5 nights per harvest moon period |
| Winter months | 5-10 nights per winter |
| During forest fire season | 10-15 nights per fire season |
| After major volcanic eruptions | 10-20 nights in a 3-6 month period |
So while not an everyday occurrence, orange moons happen with some regularity and are often predictable based on seasonal conditions, smoke or dust in the atmosphere, and lunar illumination and position. With patience and planning, nearly anyone can experience this visual treat first-hand.
The Science Behind the Orange Moon
Scientifically, the orange or reddish tint of the moon is caused by how light from the sun interacts with the Earth’s atmosphere. Shorter wavelength blue light is more readily scattered by air molecules and fine particulates than longer wavelength red light. When the moon is low on the horizon, its light must travel a greater distance through the atmosphere to reach our eyes compared to when the moon is overhead. This increased atmospheric path length results in more scattering of blue light, making the moon appear yellow, orange or red.
The degree of scattering depends on the thickness of atmosphere and the presence of scattering particles like dust or smoke. Conditions that enhance scattering include:
- Low lunar position – nearer the horizon
- Dust storms
- Forest fire smoke
- Volcanic ash clouds
- Haze, humidity or thin clouds
The autumn harvest moon is well known for its vivid orange color. Its low angle around the time of sunset couples with the typically dry, dusty conditions of early fall to create the perfect scattering environment. The large amount of fine particulate matter in smoke from forest fires also enhances the effect significantly.
History and Mythology of the Orange Moon
Unusual looking moons have inspired mythological stories and superstitions across cultures for millennia. Here are some examples of how orange moons have featured in the history and folklore of different civilizations:
- Greek mythology – Stories tell of the moon goddess Artemis shooting silver arrows at the moon, causing it to glow orange as if bleeding.
- Aztec mythology – The Aztecs believed an orange moon represented fire spewing out as a warning or omen from the gods.
- Chinese folklore – Orange moons symbolized the challenge of passing crucial tests, relating the color to stress and anxiety.
- Egyptian mythology – An orange moon was thought to be the eye of the falcon god Horus glowing brightly in the sky.
- Mayan culture – Orange moons were seen as messengers from the spirit world hinting at supernatural forces at play.
In many cultures, an orange moon was traditionally seen as a symbol of power, wisdom, growth or achievement. But the unearthly color also provoked unease and signaled unpredictability or supernatural forces to many ancient societies.
Orange Moon Superstitions
The unique appearance of an orange moon gives rise to all sorts of superstitious beliefs about its meaning and impact. Here are some common folklore concepts associated with observing an orange moon:
- Foretells conflict, volatility or unrest
- Marks a time of magical power and possibility
- Indicates a period of personal growth or heightened awareness
- Signals a good time to pursue goals and opportunities
- Means a test or challenge is coming soon
- Shows a time of power for carrying out spells and rituals
- Reveals a potent time for connecting with spiritual forces
- Indicates passion, creativity, emotions and intuitions will be strong
So the sight of an orange moon sparks a range of mystical associations – from unease about impending struggles to excitement about times of opportunity and heightened energies. These meanings and superstitions have endured through generations and still influence how people view this lunar phenomenon today.
Conclusion
In summary, the moon can take on an orange or reddish glow due to the effects of scattering as its light passes through the Earth’s atmosphere near the horizon. This occurs more often in fall, winter months, during prominent dust or smoke events, and following volcanic eruptions. Photographing the orange moon requires careful camera settings and timing for best results. While not extremely rare, these colorful moons often have mystical and superstitious lore surrounding them across cultures. So an orange moon is both a visual spectacle and a time of spiritual symbolism for skywatchers throughout history.
