Have you ever wondered why astrophotographers use red light for night sky and star photography? In this article, I am going to share with you the reasons why red lights are often used in astrophotography.
Red light is used in astrophotography because it has the least effect on night vision. That is, it helps with maintaining night vision. Before I explain in detail why astrophotographers use red flashlights and the importance of red light in dark adaptations, you need to know how our eyes are designed to see in the dark.
Similar Articles you may like to read –
Is 24mm wide enough for astrophotography?
How Many Megapixels Are Good For Astrophotography?
Can you do astrophotography during a full moon?
Can I Use 50mm Lens For Astrophotography?
What color light destroys night vision?
Smartphone flashlights and other bright white lights destroy night vision faster than anything. Therefore, we recommend using red light when taking pictures outdoors at night.
How do our eyes see in the dark?
Our eyes are good at naturally adjusting to diverse lighting conditions due to different parts of the eyes working together. They allow us to see in a wide range of lighting conditions.
When you are in a bright area, the pupil (the eye’s aperture) will contract to physically barricade the amount of light entering the retina-the part of the eye that processes light from photons into 3-dimensional images.
Conversely, the pupil will dilate or open very wide in dark environments, allowing more light to enter our retinas; and making it easier for us to see in dim light situations.
You need to know that our eyes have and use two distinguishable types of cells to see light. They use the:
- Rod cells; and
- Cone cells
Rods are the photoreceptor cells in the retina that make night vision possible. They can see only black and white and have very poor resolution. On the other hand, cones are responsible for color vision and fine details but are less sensitive to light when compared with rods.
In fact, a light barely seen by the rod cells must be increased in brightness 1,000 times before the cone cells can pick it up, according to expert findings. However, both cells contain light-sensitive chemicals called photopigments.
Rods have a photopigment called Rhodopsin, which increases sensitivity and allows us to see in poorly lit environments. However, when a bright light is introduced into a dark surrounding, these protein pigments, called Rhodopsin, will decay, reducing our eyes’ sensitivity to low light.
When this happens, it can take thirty to forty-five minutes or more to get our eyes to re-adapt to the darkness. This implies that bright white lights are not favorable for shooting sky objects in the dark. We have had enough of optometry in this article; let us come back to astrophotography.
Here is why astrophotographers use red light
Astrophotographers use red lights because they do not trigger the decomposition or neutralization of the rhodopsin photopigment. So, red lights are used to maintain night vision when clicking night sky objects, such as the stars, Milky Way, and planets.
Red light has the longest wavelengths of around 780 nanometers, which are too high for rod cells to detect. While on the contrary, it is the highest wavelength that the cone cells can detect. This makes red light the perfect lighting option for maintaining night vision.
More articles you may like to read –
Why are my astrophotography photos blurry? How do you fix it?
Can I Use 50mm Lens For Astrophotography?
How To Photograph The Sun And Make It Look Large In Photos?
Should I shoot in RAW for astrophotography?
Consequently, red light is used in astrophotography because it does not spoil night vision. This insinuates that smartphone flashlights or bright white lights are not ideal and should not be used when taking pictures of the night sky.
In conclusion, red light is the best lighting option for astrophotography. It helps astrophotographers and astronomers maintain scotopic vision when shooting the night sky or stargazing.