Opposition This Month Neptune reaches opposition this month which places it well for evening observations. The planet is in the constellation of Aquarius. This makes it a reasonably easy target for serious amateurs. You will need a telescope of some size, larger than six inches in diameter, to hope to find this distant planet. Here’s Neptune’s path through Aquarius for the next few years. It does take 165 years for the planet to orbit the Sun once, so it takes its time crawling along the ecliptic. In a fair sized telescope under dark skies, you may be able to spot this distant planet. I have seen it a dozen times or so in nearly fifty years of observing.