I said it once, and I’ll say it again – always use a solar filter!!! Our star has many features that amateur astronomers can observe. For some you will not need more than a telescope (and a filter!), for others you will have to invest in more expensive equipment.
Observe the Sun with solar glasses
I don’t mean the regular sunglasses that you’d wear everyday. You all have seen them, usually advertised before solar eclipses. They are made from special film/foil that is acting as a filter. You could also smoke a glass and use it, but I do not recommend it. Another way of homemade glasses is using a photographing film or a wielder’s mask/glass. Keep in mind that whenever you use homemade sunglasses, you should be even more careful, because any imperfection in your protective gear could damage your vision. After all, professionally manufactured sunglasses are not that expensive and it’s not worth putting your eyes at risk. Whatever you use, do not look through it for more than a few minutes. Take a brake for a few moments, and let your eyes relax. Then you may observe the Sun again.
Observe the Sun with specialized telescopes
There are some special types of telescopes that will allow you to see features of the Sun you could see only during total solar eclipses. I’m talking about the solar flares/prominences. You could see them using telescope with an Hα filter. Such filters are quite expensive, and the cheapest “solar telescopes” (regular telescope + Hα filter mounted on the objective lens) are around $500. And these telescopes are very small – 40-50 mm, f/10 or something like that. The resolution won’t be great, but at least you could see the solar flares (if they are big enough).
Observe the Sun using telescopes/binoculars
Use a solar filter!!! There is no way around it when you observe the Sun with magnifying system. Even when the Sun is just above the horizon, remember that all the light that enters your telescope is going into your eye. Think about the following example. The pupil of your eye has a diameter of 5 mm (on average). Let say you have small, 100 mm (4 inches) telescope. In this case the Sun will appear 400x brighter!!! Recall how hard it is to look at the rising sun? Now imagine how it will be if the light was 400x more intense!
There are two types of solar filters – one that you put in front of the telescope (objective filter) and one that you put on the eyepiece. The second one is not widely used, and there is a reason why. Due to the fact that the light coming from the objective/mirror is highly concentrated when it reaches the eyepiece, such filters overheat quite fast. At such heat, any imperfection in the filter could make it crack, and thus lead to blindness. That is the reason I do not recommend eyepiece solar filters.
Depending on the filter, the Sun might look white, orange, red or even blue. This is caused by different materials manufacturers use to build the filters.
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