1) Astronomical observations in most cases are passive in relation to the objects under study; 2) many cosmic phenomena proceed so slowly that their observations would require enormous periods of time; 3) we observe the position of celestial bodies and their movement from the Earth, which itself is in motion – revolves around its axis and revolves around the Sun; 4) it is impossible to carry out repeated experiments (each observation is unique); 5) light from distant objects takes so long that we observe objects as they were in the distant past. (The order in which the features are listed can be arbitrary.)
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.