Viewing the Sun’s brilliant face can be very rewarding — whether it’s to see a simple sunspot grouping, to trace out a prominence high above the limb, or to watch the Moon’s silhouette march across the brilliant disk during a solar eclipse. Learning how to look at the Sun allows you all the benefits of sungazing without any of the inherent risks.
While it’s easy to learn how to look at the Sun as there are several right ways, there are also many wrong ways to view the Sun. The danger is obvious: it’s disk is so bright that prolonged, direct exposure can cause permanent damage to the retina, leading to loss of vision or blindness. To observe the Sun safely, you need to filter out more than 99% of the Sun’s light before it reaches your eyes.
Here is some practical advice on how to look at the Sun to safely observe sunspots and solar eclipses alike.
There are numerous ways you can observe the beauty of the Sun with complete confidence that nothing bad will happen to your eyes. If you’re observing the Sun without any optical aid, all you really need are low-cost solar observing glasses, like the Baader AstroSolar Viewers.
Please make sure to not use “filters” such as smoked glass, stacked sunglasses, polarised filters (without the aid of a specialised solar filter), camera filters, candy wrappers, or compact discs. They might reduce the Sun’s glare, but enough harmful radiation can sneak through to damage your eyes. Only use materials specifically manufactured for safe solar viewing.
If you want to observe the Sun through a telescope, there are many options. Because binoculars and telescopes concentrate the Sun’s blazing light, it’s even more crucial to use safe filters. Make sure to avoid any filter that is placed at the eyepiece end of the scope. The concentrated sunlight will probably destroy such a filter, followed shortly thereafter by your vision.
The easiest and least expensive option is to use a sheet of solar-filter material, such as Baader’s Saftey Film, which is specially made for telescope use. Make sure to place the filter material at the front end of your telescope, and to cover the entire opening.
These filters show you the Sun’s visible surface (the photosphere) in its natural “white” light, though you’ll see the disk as pale yellow, orange, or blue, depending on the filter type. They allow you to gaze at the Sun for hours with no risk. Make sure your filter is securely attached to the front of the scope, so there is zero possibility that it will come off while viewing. To avoid damaging your finderscope, either remove it or place a cap or solar filter at its front end. Also note that safe solar filters work equally well with binoculars.
Alternatively a cardboard kit telescope, like AstroMedia’s Solar Telescope, is the perfect inexpensive way to observe the Sun through a telescope. It does not require a tripod, merely hold it up to your eye and observe the Sun like a monocular. The Solar Telescope comes with, and uses, Baader’s Saftey Film. The filter can be removed to project a 2 inch picture of the sun onto a white piece of paper.