Turn any Telescope into a Solar Telescope

This article will show you how to turn any telescope, pair of binoculars, or camera into a solar telescope by using solar safety film.

Solar safety film can be added to the front of any optical instrument and you can buy it as a plain sheet of solar safety film. You can then cut it to the size you want and mount it on the front. Before using any solar film, you should always check that it does not have any holes. To do so, you need to hold the film up to a source of light to make sure no light is shining through.

You can then attach it to your telescope or binoculars, remember if you attach it to binoculars to cover both objective lenses. Do remember to securely attach the filters so they do not fall off accidentally. Once on there you can look through there with a camera or your own eyes and you will be able to see the sun.

Another important safety step is that before doing any solar observing is to make sure you cover up the finderscopes or other optical equipment that you are not actually using. This should stop any potentially magnified stray light going into your eyes.

The most important thing when doing solar observing is always be safe, do nothing that could potentially damage your eyesight.

So, when you are trying to locate the Sun in the sky you cannot look through a finderscope as that would be incredibly dangerous unless you have also got a solar filter on top of that.

An alternative is to move the telescope until the shadow of the telescope tube is as small as possible and once you have done this, you know you have got it pointing directly at the Sun.

A white light filter reduces all wavelengths of light equally by about 99.999%. If you have a larger aperture than 6", you can reduce the aperture when creating your solar filter. At this point, no extra light is needed. This is usually done by using an off axis solar filter. 

With a solar filter film, you can see details on the disc of the Sun, which are mainly sunspots. These are cooler patches on the Sun's surface, which is why they appear dark. You might also see Faculae, which occur at sunspots and above the photosphere and are best seen along the edge of the Sun's limb, where the darkening enhances their contrast.

So what can you observe with Solar Safety Film?

The main observations you can make is to:

  • Map the progression of sunspots across the surface of the Sun.
  • Capture transits of Venus or Mercury as they pass in front of the Sun. 
  • As well as watch solar eclipses.

If you want to see any other features such as the photosphere or solar flares then you will need a hydrogen alpha telescope.

To see examples of how to turn your telescope into a solar telescope, please watch the episode below.

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