### Instruction:

Extract the cause and effect entities from the following sentence:
For the brightest targets it will be possible to obtain high quality spectra in a single visit; for fainter targets the necessary signal-to-noise will be built up through repeated visits over the mission lifetime

### Assistant:

KEYWORD: it
CONDITION: will be built up through repeated visits over the mission lifetime.
VARIABLE: the necessary signal-to-noise
CAUSE_1: the brightest targets
EFFECT_1: will be possible to obtain high quality spectra in a single visit
CAUSE_2: fainter targets
EFFECT_2: the necessary signal-to-noise will be built up through repeated visits over the mission lifetime.

