re: I have a question.
Well - Hubble's silver insulation has become increasingly 'dull' over time - just by looking at the photos taken by EVA Astronauts you can see that the insulation has degreaded from looking like aluminium foil into looking more like brittle silver paper, less reflective certainly.
Also - it's had considerably smaller solar arrays fitted, but due to increases in solar panel technology, they now produce more power than it used to have. Those two factors combined could certainly mean it would appear quite a lot dimmer than it might have before.
Doug