General Question

RedDeerGuy1's avatar

Is the uv radiation from stars magnified enough to damage ones eyes when viewed from a telescope?

Asked by RedDeerGuy1 (24945points) August 28th, 2017

Play along. Ok . I am wondering if it is possible. Please no trolling. In general. How much magnification is necessary to damage ones eyes?

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8 Answers

ARE_you_kidding_me's avatar

Well, omitting the sun I don’t think you will be able to damage your eyes looking at the night sky through a scope. There is just not enough light to concentrate.

elbanditoroso's avatar

The scope acts a filter to block the UV radiation.

RedDeerGuy1's avatar

@ARE_you_kidding_me What about long term looking?

seawulf575's avatar

Damage from radiation can be impacted by several things: Time, Distance, and Shielding. The longer you spend next to a radiation source, the more damage you can get from the exposure. Likewise, distance. The farther you are away from a source, the less radiation can impact you. And lastly is shielding. Depending on the type of radiation, different shielding can be applied. Think of shielding as something that will block the radiation. Using a lightbulb as an example: The more time you spend in the room with a lightbulb, the more light hits your body. Light is the radiation in this case. If you are farther away, less of the light hits you. All the light is coming from a distinct point and radiating outward. Up close, many of the light rays radiating outward will hit you. Farther away, because of the angle in which they are being ejected from the bulb, some will hit you but some will go over, under, or around you. And if you turn on a light and then step behind a wall, all of the direct light is shielded so you are protected from it.
In the case of the starlight, the radiation is extremely far away so very few actual rays are making their way to Earth. Magnifying them doesn’t significantly increase the damage from the rays because they are so few. Additionally, our atmosphere adds quite a bit of shielding for us. I personally wouldn’t worry about damaging your eyes looking at stars with or without a telescope.

Espiritus_Corvus's avatar

Rarebear has never complained of eye problems and he has been looking through telescopes for quite some time.

LuckyGuy's avatar

No for 2 reasons.
1) Opitical glass used in lenses and eyepieces does not pass UV. If you specifically need to measure the UV the optics need to be made of quartz.
2) Think of the human eye as a camera with a focal length of about 22 mm and an aperture that varies from ~7mm in the dark to ~2 mm in bright light. That translates to an f-number of f/3 (widest opening) to about f/11 (smallest opening). A typical good telescope has a 8 inch mirror (200mm) and a focal length of 1200 mm. That means the f-number of the telescope optics set is f/6.0 That is ¼ as bright as the human eye at its widest, f/3.0.
To match the human eye the lens or mirror would need to be 16 inches in diameter and still retain the 1200mm focal length. It would take a very specialized lens to match the eye.

Rarebear's avatar

@Espiritus_Corvus I do have bad astigmatism, but it’s not from looking through telescope.

Although I actually don’t “look” through scopes much anymore. 95% of the time I am looking at a computer screen when I am doing my observing as I am doing photography.

But @RedDeerGuy1 no. The light is orders of magnitude too dim to cause any damage.

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