Planet Neptune | Solar System | The Utah Skies Report
The planet Neptune, is currently rising several hours before the sun, leaving you precious little time to view the 8th rock. To speed up your acquisition of the planet, look just east of south before first light. Find Deneb Ageldi; Neptune is just about 4.5° west and north of "the water goat's tail". At just a touch brighter than mag 8, Neptune should be visible as a faint star-like object in binoculars or as a bluish object in a telescope. Once you've found it, higher powers will clearly reveal the disk of the planet .
This beautiful image of Neptune and its moon, Triton, was taken by the Voyager 2 spacecraft from a perspective that will never be had from Earth. Interesting to note is the gray hue of the planet in this image. The atmosphere of the planet preferentially scatters the light forward from this vantage and so removes the bluish tinge, and reddens the color.
Facts & Figures
The eighth planet from the Sun, Neptune was the first planet located through mathematical predictions rather than through regular observations of the sky. When Uranus didn't travel exactly as astronomers expected it to, two mathematicians, working independently of each other, proposed the position and mass of another, as yet unknown planet that could account for Uranus' orbit. Although "the establishment" ignored the predictions, a young astronomer decided to look for the predicted planet. Thus, Neptune was discovered in 1846. Seventeen days later, its largest moon, Triton, was also discovered.
Nearly 4.5 billion kilometers from the Sun, Neptune orbits the Sun once every 165 years, and therefore it has not quite made a full circle around the Sun since it was discovered. It is invisible to the naked eye because of its extreme distance from Earth. Interestingly, due to Pluto's unusual elliptical orbit, Neptune is actually the farthest planet from the Sun for a 20-year period out of every 248 Earth years.