On June 3, six planets form a straight line through the pre-dawn sky that stretches from Jupiter on the eastern end (closest to the horizon) up through Mercury, Uranus, Mars, and Neptune, to Saturn on the western end, highest in the sky before sunrise. Some 20 minutes before sunrise, all six planets should be visible, though note that Uranus (magnitude 5.9) and Neptune (magnitude 7.

will be too faint for naked-eye observing and, although they’re present in the lineup, will need binoculars or a telescope to spot. But Jupiter (magnitude –2), Mercury (magnitude –1), Mars (magnitude 1), and Saturn (magnitude 1) will all stand out clearly to the naked eye in a line spanning some 73° on the sky.
What’s more, a delicate waning crescent Moon is crashing the party as well, standing just to the lower left of Mars. Note, however, that our Moon is not perfectly in line — that’s because Luna’s orbit is tilted some 5° with respect to the ecliptic.