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Anticrepuscular rays

What are they?

They are a metrological optical phenomenon that occur opposite the sunin the sky. They are essentially parallel, but look like they converge on the anti-solar point due to the single point perspective. Like how long roads look like they go to a single point rather than staying the same with until the horizon. The anti-solar point is simply put, a point opposite the sun from the observers perspective. So on a sunny day that point is where (on the other side of the world) the shadow of your head
touches the ground. So, the antisolar point moves as the observer moves. The antisolar point is also centerpoint of rainbows, with the rainbow visible at 42 degrees, centered around this point. The anti-solar point is always below the horizon when the sun is up. These rays are most common around sunrise and sunset due to the light scattering from the atmosphere. Light scattering (by particles) happens when small particles such as ice crystals, dust, salty air, or atmospheric particles scatter light causing halos, the blue colour of the sky, and in this case, the anticrepuscular rays that we saw on Wednesday evening just before dinner

Another thing that the antisolar point should not be confused with is the anthelic point, which is opposite the sun, but at the same elevation, so is therefore located on the parhelic circle.

The other side (near the sun) you get sun dogs and halos. These occur at 22 degrees from the sun, and are once again a metrological optical phenomenon occurring when the light is reflected and refracted through (mainly) ice crystals in the sky. The ice crystals behave like prisms and mirrors, sending shafts of light in particular directions. Before weather forecasting, atmospheric optical phenomena like halos were used as part of weather lore. They typically signified that rain would fall
within 24 hours, since the cirrostratus clouds that cause the halos and sundogs can signify an approaching frontal system. You can also get halos from the moon, and sometimes other bright planets.

This blog was written by Jo, with help from their mother over email, about where to even start looking

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