Neptune Opposition 2016 – Everything You Need to Know

Neptune Opposition 2016 – Everything You Need to Know

Neptune Opposition 2016 – Everything You Need to Know

The first week of September is your 2016 chance to catch elusive Neptune, in opposition. I say “elusive,” simply because Neptune is the eighth, and farthest planet form Earth, making it tough to spot! However, September 1 and 2 will deliver your best observational opportunities for the year.

What is Opposition?


Diagram of how a planetary opposition works. Earth and the planet are at their closest distance, and the planet’s facing side is fully sunlit.

In astronomy, opposition occurs when Earth passes in between the Sun and a planet whose orbit is out beyond Earth’s. The result of this is the side of the planet that is facing us is drenched fully in Sunlight and at its brightest. This makes all planets, even the more distant ones, easier to spot in the sky.

Opposition is also the time of year in which Earth is at its closest distance to the planet it is in opposition with, in this case, Neptune. On September 1, Neptune will be 2.69-billion miles from Earth. This is still a vast distance, but it is, indeed closer than usual 2.8 or 2.9-billion-mile distance.

Between the abnormal brightness and closer proximity, this will give backyard astronomers a leg-up in spotting the blue ice giant.

When Can I See the Neptune Opposition 2016?


Late night on September 1 through early morning on September 2, will be the optimal viewing time. At this point Neptune will be at its closest position to Earth for 2016 and at full opposition.

Though Neptune will still be unusually close through around September 6, its opposition will end on September 2. As mentioned above, this will be extremely helpful in spotting the planet.

Where Can I See the Neptune Opposition 2016?

On September 1, Neptune will slowly begin rising in the eastern sky around 8:30 p.m. (local time). It will continue across the sky, reaching its highest points between 12:00 a.m. and 1:30 a.m. on September 2. Finally, it will work its way down, setting in the western sky around the time of sunrise.

How Can I See the Neptune Opposition 2016?

As most of us know, Neptune is a challenging astronomical target. It is the fourth largest planet. In fact, it is much larger than Earth, Mars and Venus, all of which we can see with our naked eye. But, it is also 2.8 billion miles from the Sun, and has a relatively dim blue coloration. These reasons, and the sheer size of the night sky, make Neptune tough to track down!

Observing Neptune in opposition will inevitably require optical aids (binoculars/telescope), sky maps and persistence. For something so distant, star-hopping will likely be a must.


Binoculars will certainly allow you to observe Neptune. It will not look like anything more than a rather dim star. This is part of why it is so difficult to track down. However, depending on your sky conditions, binocular’s power and your eyesight, you may resolve slightly blue coloration. This, if anything will help confirm your observation.


Even higher aperture telescopes (8”/203mm and up) will require both focus and expectation management. For those of you who have observed Neptune’s slightly easier and brighter twin, Uranus, you know the end results. Both planets will appear as a pale blue dot, not terribly bigger than a star in your eyepiece.

Larger telescopes and proper eyepieces will reveal a pea-sized object with definite blue color. Though no surface detail will resolve, confirming you have spotted Neptune should be almost instant.

Helpful Resources:

Uranus/Neptune Finder Charts – Helpful maps from Sky & Telescope

Stellarium Software – A free software program that will forever change your observing

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