Being aware of the exact time it will get dark is essential for photographers and astronomers. The clear sky and dark skies are vital to the night sky as it is an ideal golden hour for photography.
To comprehend the time it takes to reach darkness is far more complicated than you think. It depends on several factors such as distance to Equator altitudes, distance to the Equator, and the different seasons.
The darkness sets in about 20 or 30 minutes following sunset near the equator. However, it can take between 70 to 100 minutes before the night is settled up north.
Why is it that it gets darker in winter?
If you remember, in science class, the planet we live on forms part of the more extensive system that revolves in the sun’s direction. We receive from this star vital energy and light. It is important to note that Earth lies on the title axis, which means that a part of it will be tilted towards the sun while another is located away from it.
Thus, the Earth receives different amounts of sunlight during different seasons. This leads to the Northern Hemisphere receiving more sunshine and longer days in summer. The reverse is true in winter. This is why it’s colder due to lower solar radiation due to fewer contact hours.
The same applies (although at different periods) to people living in the Southern Hemisphere. However, those who live near the Equator (the centerline that runs around the globe) can enjoy nights and days generally equal.
What exactly is Astronomical Twilight?
You might have heard of astronomical Twilight (yes, it’s an actual thing); however, it is the final and darkest of the three recognized twilight phases.
Twilight phases are determined by how much the sun is from the horizon.
Civil Twilight – begins at sunset (the centre of the sun is located at zero degrees elevation) until it’s at least 6deg lower than the horizontal line.
Nautical Twilight starts when the twilight of civil society ends and lasts until the central point of the sun is 12 degrees below the horizon.
Astronomical Twilight – the last and most dark of the Twilights. It starts at 12 degrees below the horizon and closes when it is 18deg below.
When the sun is further than 18 degrees below the horizon, it’s officially “night”, and there isn’t any sunlight that can illuminate your area, making it the perfect time to take photographs from the sky at night.
There are Different Types of Twilight
Twilight is when sunlight remains visible even though the Sun is not visible from the horizon. Sunset in the morning and evening twilight with three distinct periods: civil, nautical, and astronomical.
Each of these phases is unique and provides a different experience for astronomers and photographers. Let’s take a look at what each phrase signifies.
The civil twilight period starts at sunset and continues until the middle of the Sun is 6o below the horizon. The objects are visible on the ground, and artificial lighting is not required if fog is absent. Astronomers are able easily to spot Mercury and Venus in the golden hour.
This phase begins when the geometric centre of our Sun is between 6o and 12o above the horizon. At this point, it is when anyone with a naked eye can see most stars. Photographers can capture images; however, they will be blurry and dark.
The word “nautical” refers to sailors that navigate themselves using famous stars and the visible Horizon.
The astronomical twilight starts when the Sun’s centre gets to 12o and lasts until 18o. After that, the actual night starts and the two phases are quite similar to those of newcomers.
Astronomical dusk is an excellent time for astronomers to look at the sky. It is also a great time to shoot astrophotography. Photographers who are not professional cannot capture decent photos unless they focus on an area that is illuminated. The objects are difficult to distinguish, and colours aren’t apparent.
Solstice and Equinox
Twice a year, it is the case that the daytime is the same as the nighttime. These times are referred to as Equinoxes. They occur when the central point of the Sun is just above the Equator. In these instances, a reflection of sunlight causes the Sun to appear to be over the horizon, even though it’s lower than the skyline.
How long will it take to go dark following sunset?
If you watch the sunset that it does not immediately go to darkness. It’s all to be due to the spherical shape of the planet. Even though the sun has reached the horizon, it can still shine upon the atmosphere over the Earth’s surface. This is due to the interaction of light with gas molecules, causing the light to scatter.
The nighttime phase of the sky is referred to as the twilight. There are three phases of evening.
Civil Twilight. This is the time when it’s sufficient light to be able to see.
Nautical Twilight. The phenomenon occurs at the time when objects appear as silhouettes. Stars and constellations are visible from the skies.
Astronomical Twilight. It’s what you call night. It’s genuinely dark, making it the perfect moment to see distant objects.
Experts say it takes about 70 to 100 minutes for the environment to pass through the three stages. As a result, it is believed that it will be dark 1 hour a quarter after sunset.
Why doesn’t the sunrise earlier during the longest days of the year?
Each year’s most extended and shorter day has the highest and the tiny amount of daytime. This is because they fall on the day of solstices, usually between 21 June or 21 December in the UK and the majority of the Northern hemisphere.
Many people know that the sunrise is getting later every day after the Winter Solstice comes around. The reason has been the slight variance in the duration of “natural days during all of the time (the longest day in nature is about 50 seconds more than shorter).