Build a solar funnel
Our solar funnel is a hollow cone with an eyepiece fitted in the narrow end and a translucent screen at the other. It uses a projection technique to disperse sunlight over a wide area and onto the screen. Because the eyepiece is internal, there is no way for you to accidentally look into the light path.
The length of the cone is calculated to suit small refracting telescopes with a focal length between 300mm and 1,000mm. Because the aperture of such telescopes will be relatively small and they lack internal structures, heat build-up is not a problem. If your scope’s main lens is larger than 3 inches we recommend reducing the effective aperture by using a cardboard mask with a smaller hole (2 inches) cut in the centre and taped over the dew shield. Solar funnels are less suitable for use with Newtonian reflectors as these telescopes have large apertures and the secondary mirror can be damaged by heat.
Any eyepiece with a focal length between 12mm and 25mm produces acceptable results. After capping your main lens and any accessories like finderscopes, and with your eyepiece in the narrow end of the funnel, position it in the focuser. Align the telescope with the Sun: the easiest way is to line up your scope so its shadow becomes small and round. Remove the lens cap (or uncover the opening of your aperture reducer) and you should see a bright image of our star somewhere on your screen.
Make adjustments to the mount and focuser to centralise the image and bring out any fine details on the Sun’s surface. You should be treated to a display of sunspots, which will appear dark against the bright surface.