What Schrödinger’s cat REALLY means

I had always been told that under quantum physics any type of observation will alter the outcome. So the Schrodinger Cat  thought experiment stated that there was a viral of poisonous cat that will break when hit by a particle that may or may not be emitted by an element within a certain period of time. And that the idea was the cat was in an indeterminate state, neither dear or alive until you open the box and observed the cat's current status at the end of the time period. Also any observations trying to detect the emission of the particle will effect the outcome of the experiment. So would not gieger counter in the box to detect the emission of the particle and trigger a device to break the vial affect the outcome and thus the thought experiment?