Use only new equipment. Use a very strong telescope. Project image onto a piece of cardboard. Look at the Sun only in the morning.
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: What precaution must be taken by students when making observations of the Sun?
Possibilities:
- Use only new equipment.
- Use a very strong telescope.
- Project image onto a piece of cardboard.
- Look at the Sun only in the morning.

Project image onto a piece of cardboard.