Red at night, shepherd's delight. Red in the morning, shepherd's warning!
Cable Beach is one of our favourite parts of the Country. When we originally came here in 2017 we instantly wanted to place a cache here talking about the phenomenon, we couldn’t quite pass it as an Earth Cache so when we were rewarded with a Virtual Reward cache in 2019 we instantly thought of Cable Beach and it’s crepuscular rays.
**********TO LOG THIS VIRTUAL CACHE WE REQUIRE YOU TO SIMPLY PHOTOGRAPH CABLE BEACH FROM THE POSTED COORDINATES LOOKING WEST WITH A PERSONAL ITEM THAT IDENTIFIES YOUR TEAM.**********
We have made this cache a D1/T1 for everyone to enjoy. We have left the learning tasks as optional and have made the cache for all to enjoy.
Please note this cache is available 24/7 we highly reccomend visiting during Sunset hours.To check sunset times click here
Take care of your eyes. We advise wearing sunglasses to if viewing/photographing the Sunset. Never stare at the sun/look directly at it at any other time than sunrise or sunset. .
ADDITIONAL INFORMATION YOU MIGHT FIND INTERESTING:
Why are the sunsets so good here? Geographic location and Topography are the two main reasons.
Firstly let's clarify what the Horizon is: by definition, the horizon is the apparent line that separates earth from sky, the line that divides all visible directions into two categories: those that intersect the Earth's surface, and those that do not. At many locations, the true horizon is obscured by trees, buildings, mountains, etc., and the resulting intersection of earth and sky is called the visible horizon. When looking at a sea from a shore, the part of the sea closest to the horizon is called the offing.
How far away is the Horizon? Typically humans see further along the Earth's curved surface than a simple geometric calculation allows for because of refraction error. If the ground, or water, surface is colder than the air above it, a cold, dense layer of air forms close to the surface, causing light to be refracted downward as it travels, and therefore, to some extent, to go around the curvature of the Earth. The reverse happens if the ground is hotter than the air above it, as often happens in deserts, producing mirages. However, ignoring the effect of atmospheric refraction, distance to the horizon from an observer close to the Earth's surface is about D = 3.57 √ h where D is in kilometres and h is height above ground level in metres. The constant 3.57 has units of km/m½.M
Examples:
For an observer standing on the ground with h = 1.70 metres, the horizon is at a distance of 4.7 kilometres.
For an observer standing on the ground with h = 2 metres, the horizon is at a distance of 5 kilometres. .
For an observer standing on a hill or tower of 100 metres in height, the horizon is at a distance of 36 kilometres. .
By definition Sunset or Sundown is the daily disappearance of the Sun below the horizon as a result of Earth's rotation. The Sun will set exactly due west at the equator on the spring and autumn equinoxes, each of which occurs only once a year.
The time of sunset is defined in astronomy as the moment when the trailing edge of the Sun's disk disappears below the horizon. Near to the horizon, atmospheric refraction causes the ray path of light from the Sun to be distorted to such an extent that geometrically the Sun's disk is already about one diameter below the horizon when a sunset is observed.
Sunset is distinct from twilight, which has three phases;
The first being civil twilight, which begins once the Sun has disappeared below the horizon, and continues until it descends to 6 degrees below the horizon.
The second phase is nautical twilight, between 6 and 12 degrees below the horizon.
The third is astronomical twilight, which is the period when the Sun is between 12 and 18 degrees below the horizon. Dusk is at the very end of astronomical twilight, and is the darkest moment of twilight just before night. Night occurs when the Sun reaches 18 degrees below the horizon and no longer illuminates the sky.
Why beautiful colours during Sunrise and Sunset? Firstly we can guarantee there is always a good Sunset experience at Cable beach!
The atmosphere acts as a giant lens which refracts low sunset rays into long curved paths passing through up to 40 times as much air than the rays from a high midday sun. Air, dust, aerosols and water drops scatter and absorb the rays throughout their long passage.
Reds, yellows and golds arise because the air itself, small dust and aerosol particles smaller than the wavelengths of visible light, Rayleigh scatterers, scatter short wavelength blue and green rays much more strongly than longer wavelength yellow and red. The remaining direct unscattered light is dimmed but relatively enriched in reds and yellows. Absorption of specific green and blue wavelengths by ozone and water vapour molecules redden the light further. The sunset rays are sometimes reflected back and forth between clouds and the ground.
When the upper atmosphere contains extra fine dust from a volcanic eruption skies are reddened further.
Large dust particles and suspended water droplets scatter light differently, they are Mie scatterers and do not produce vivid red sunsets, they merely dim the sun.
What are Sunbeams? They are actually Crepuscular rays, which are rays of sunlight that appear to radiate from the point in the sky where the sun is located. These rays, which stream through gaps in clouds (particularly stratocumulus0 or between other objects (land formations, trees etc), are columns of sunlit air separated by darker cloud-shadowed regions. Despite seeming to converge at a point, the rays are in fact near-parallel shafts of sunlight.
Anticrepuscular rays are similar to crepuscular rays, but seen opposite the sun in the sky. Anticrepuscular rays are near-parallel, but appear to converge at the antisolar point because of linear perspective. Anticrepuscular rays are most frequently visible near sunrise or sunset. Crepuscular rays are usually much brighter than anticrepuscular rays. This is because for crepuscular rays, seen on the same side of the sky as the sun, the atmospheric light scattering and making them visible is taking place at small angles.
It is possible to see the occasional Sunset mirage here at Cable Beach. A Sunset mirage is when two or more images of the sun, are seen when its low slanting rays are unusually refracted between air layers of different temperature. Usually the air temperature falls smoothly with increasing height. The most we then see is a slightly flattened sun. A mirage needs more severe temperature variations.
A Solar Halo - also known as a nimbus, icebow or gloriole - phenomenon produced by ice crystals creating colored or white arcs and spots in the sky. Many are near the sun or moon but others are elsewhere and even in the opposite part of the sky. They can also form around artificial lights in very cold weather when ice crystals called diamond dust are floating in the nearby air.
Parhelion or Sundogs are considered relatively common, they typically, but not exclusively, appear when around sunrise and sunset, when the sun us low and the atmosphere is filled with ice crystals forming cirrus clouds. Diamond dust and fog can also produce them. They are often bright white patches of light looking much like the sun or a comet, to the untrained eye they appear as a Halo.
Green flashes are phenomena that sometimes occur just before sunset, when the conditions are right, a green spot is visible above the upper limb of the Sun's disk. The green appearance usually lasts for no more than a second or two. Rarely, the green flash can resemble a green ray shooting up from the sunset point. Green flashes occur because the atmosphere can cause the light from the sun to separate out into different colours.
A rainbow is a phenomenon that is caused by reflection, refraction and dispersion of light in water droplets resulting in a spectrum of light appearing in the sky. It takes the form of a multicoloured circular arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun. Rainbows can be full circles. However, the observer normally sees only an arc formed by illuminated droplets above the ground, and centered on a line from the sun to the observer's eye.
Once the sun has set look eastwards. A low horizon is needed. As twilight deepens a dark band rises upwards from the horizon, The band is the shadow of the Earth on the atmosphere. Immediately above, where the evening air is still lit, glows a pink band called the anti-twilight arch or "Belt of Venus". The pink arises from scattered and deeply reddened sunlight mingling with the deep blues of the eastern sky. In the morning look westwards before sunrise to watch the shadow sinking towards the horizon.
******************THE OPTIONAL TASKS****************** we have listed for you are below, the first 20 teams who complete these OPTIONAL tasks with reasonable answers will have a TeamThommo Path Tag mailed out to them upon request.
We repeat these are OPTIONAL TASKS.
1. How long did the sun take to set?
2. Identify the depth of colour seen in the sunset and explain the factors that have contributed to this?
3. Identify any other phenomenon you can see in this evening's sunset?
4. Using the formula above, (NOTE: you will need to know altitude of the location you are standing & your height) how far away is the horizon for you?
5. Why would you not expect to see a rainbow here whilst completing this Virtual Cache?
6. Take a photo and post it with you log of yourself (or team member) with a broom at Broome. (Geo mum loves puns and was excited to buy a new broom when she got to Broome) BUT REMEMBER never sweep after sunset since so doing will chase away happiness or hurt a wandering soul!
Another natural phenomena involving Broome’s Geographic location and Topography is the staircase to the moon. This natural phenomenon is best seen from Roebuck Bay in Broome, (reference point marked) when the full moon rises over the exposed mudflats at extremely low tide and creates a beautiful optical illusion of stairs reaching to the moon. There are limited days of the year when this phenomenon can be witnessed. Bonus points to anyone who also uploads a pic of Staircase to the Moon.
To check staircase dates click here
Source: Wikipedia, willyweather, visitbroome, atoptics.co.uk.
Virtual Rewards 2.0 - 2019/2020
This Virtual Cache is part of a limited release of Virtuals created between June 4, 2019 and June 4, 2020. Only 4,000 cache owners were given the opportunity to hide a Virtual Cache. Learn more about Virtual Rewards 2.0 on the Geocaching Blog.
