How bright is Asteroid 1I/2017 U1 (Oumuamua)?
The current visual magnitude of Asteroid 1I/2017 U1 (Oumuamua) is 37.82. Given its brightness, Asteroid 1I/2017 U1 (Oumuamua) should be visible only through long exposure photography.
The following chart is the predicted light curve (visual magnitude as a function of time) of Asteroid 1I/2017 U1 (Oumuamua), according to the most recent ephemerides data. Magnitude data is sampled with a 2 days interval and there might be inaccuracies for objects changing brightness very rapidly during the course of a few days. For comets there could be large discrepancies between the observed and predicted brightness because of their highly dynamic behaviour.