Safe Solar Observing

Looking at the Sun directly is dangerous: it will damage your eyes. You need to use approved optical systems to view the Sun, both with and without telescopes or binoculars. I highly recommend that you work with a local astronomer or a local astronomy club to get set up with the equipment you need in order to do the kind of observing you wish.

In brief, all optical systems, like telescopes, binoculars, monoculars, spotting scopes, and the like, require that you place a solar filter in FRONT of the system’s light collecting opening (the objective). You do not want unfiltered sunlight to enter your optics, as this will likely damage your optics as well as your eyes. Some small refractor telescopes can be used to project unfiltered sunlight onto a white board. DO not do this with large telescopes or with reflector telescopes or catadioptrics.

DO: 

  • Use certified solar filters. Companies like Baader (https://www.baader-planetarium.com/en/solar-observation.html) make excellent solar film for covering telescope optics.
  • Make sure that the filters cover the front of your telescope’s system, the opening where the light goes in.
  • Make sure that the filters cannot come loose and fall off the telescope when in use. Tape the filters on for protection!
  • Ask for help from someone who has done this before. Better safe than blind.
    Project the sun’s image onto white paper or board, but only with a SMALL refractor. This can damage larger telescopes, like SCTs and such. When in doubt – don’t.
  • Use Welders Filters shades 13 or 14. While #12 is also safe, it is not too comfortable. These can be placed in front of your eyes when looking directly at the sun. These are not for use with a telescope or other optical aids.

and….

  • DO NOT Use random glass filters or lenses that have been marked as solar filters. Many are not safe! This includes stacking old exposed film.
  • DO NOT Place filters at the eyepiece of the optical system: they will burn and break!
  • DO NOT Expect solar glasses to protect you from harm when using them with binoculars. They will burn and you will be hurt!
  • DO NOT Use skin sunscreen in your eyes. This does not work. Yes, people have done this. Don’t.

Other links:

Sky & Telescope Safe Solar Observing
https://www.skyandtelescope.com/observing/celestial-objects-to-watch/safe-solar-observing/