Pointing a telescope at the sun is safe and rewarding with one piece of equipment and lethal to the eye without it, and there is no middle setting. This page is about the equipment and about what the view is worth once you have it.
The rule, stated once and plainly
A filter goes over the front of the instrument before it is pointed anywhere near the sun. Not in the eyepiece, not behind the focuser, not a pair of eclipse glasses held to your eye at the back. The reason is arithmetic: a 76mm objective concentrates roughly a hundred and fifty times the energy that reaches your naked pupil, and anything placed after that concentration is in the path of a burning glass.
Take the finder off, or cap it
The most common accident on a solar session is not the main tube at all. A finder scope is a small telescope with no filter on it, and it is at eye level. Cap it or remove it before you start, every time, and check that a red dot finder is switched off so nobody puts an eye to a magnifying one out of habit.
What the view is worth
Through a white light filter the sun is a clean disc with sharply defined edges and, in an active year, several sunspot groups with dark umbrae and grey penumbrae around them. Granulation, the boiling texture of the surface, appears in steady air on a decent instrument. The sun rotates in about 27 days, so a group tracked over a week visibly moves and changes, which makes it the one object that rewards a daily look.
Questions people ask about telescope
Can you look at the sun through a telescope?
Only with a filter fitted over the front aperture of the instrument. Without one the injury is immediate and permanent.
What is a sun filter?
A filter that reduces sunlight by around a hundred thousand times across the visible and blocks the infrared, mounted over the front of a telescope, binocular or camera lens.
Can I use a telescope during the day for anything else?
Yes, and it is a good way to learn the instrument: distant buildings, hills and birds are all easy targets, and the daylight makes focusing and alignment far less frustrating than a first night does.