Solution
Special exercise to the home: estimate the total apparent magnitude of the all of naked eye visible stars (to the mag. of 6 except for Sun).
Note: this small catalogue contain stars to the distance of 20 l.y. and all of stars that are of the magnitude to 6.5 with distance limit of 50 l.y. and all of the stars on the sky of the apparent magnitude to 4.0.
Star database (each open each own database): Stars_1 Stars_2 Stars_3 Stars_4 Stars_5
Look at the interresting astronomical objects on the Astronomy Picture of the Day
See video Star size comparison at APOD and note, which is the most known giant star and how big it is.
See picture of Betelgeuse (and other picture here and the oldiest picture from 1996) and answer the question: is that real optical picture? Which only stars are visible direct with optical instruments?
See picture of colour of stars in Orion constellation and answer the question: how depends colour of stars on their temperature?