The four sentences (labelled $1,2,3,4$) below, when properly sequenced would yield a coherent paragraph. Decide on the proper sequencing of the order of the sentences and key in the sequence of the four numbers as your answer:
- It also has four movable auxiliary telescopes $1.8 \; \text{m}$ in diameter.
- Completed in $2006,$ the Very Large Telescope $\text{(VLT)}$ has four reflecting telescopes, $8.2 \; \text{m}$ in diameter that can observe objects $4 \; \text{billion}$ times weaker than can normally be seen with the naked eye.
- This configuration enables one to distinguish an astronaut on the Moon.
- When these are combined with the large telescope, they produce what is called interferometry: a simulation of the power of a mirror $16 \; \text{m}$ in diameter and the resolution of a telescope of $200 \; \text{m}.$