Peak Viewing Time for Uranus in 2021

Uranus, the enigmatic seventh planet from the Sun, will reach its opposition on November 13th, presenting a spectacular sight for stargazers. Positioned among the stars of Aries, Uranus will shine with a magnitude of +5.7, making it faintly visible to the naked eye. With its large apparent diameter, observers using a small telescope will have the opportunity to witness its recognizable blue-green disc.

Finding Uranus in the night sky will be a relatively easy task. It can be located just over 2° south of magnitude +4.3 delta Arietis, situated approximately 12° northeast of the brilliant Jupiter. Its position will allow for comfortable observations, with an altitude above 25° from around 7 pm to 4.30 am GMT. The best time to catch a glimpse of Uranus will be between 11.30 pm and midnight when it will reach its highest point at an impressive altitude of approximately 60°.

Although Uranus will be riding high in the sky, studying the planet can present challenges. Due to its small apparent diameter and lack of prominent features compared to Jupiter, observing Uranus can be demanding. However, with a telescope in the 80–100mm (~three- to four-inch) class, capable of achieving a magnification of around 100x, stargazers can expect to observe Uranus’ 3.7-arcsecond blue-green disc. For those eager to capture more intricate details, upgrading to a larger telescope, such as a 200–250mm (eight- to ten-inch) one, used at high magnification on a night with clear atmospheric conditions, may reveal subtle characteristics, particularly when using green or yellow-green filters.

Uranus is not alone in its celestial journey; it is accompanied by a significant family of moons. Amateur astronomers can readily observe five of these moons using accessible equipment. Owning a telescope in the 300mm (twelve-inch) class will allow them to spot Oberon and Titania, which are the outermost of Uranus’ five primary satellites. With magnitudes of +13.9 and +13.7, respectively, these moons will provide an exciting addition to any stargazer’s observations.

One of the most intriguing aspects of Uranus is its peculiar axial tilt. While the planets in our Solar System typically rotate upright, Uranus spins on its side. Its rotational axis is tilted by nearly 98 degrees to the ecliptic, causing it to rotate parallel to the plane of the Solar System. This remarkable characteristic affects the visibility of Uranus’ faint markings throughout the years.

Under ideal circumstances, observers can detect dusky equatorial bands on Uranus. However, their visibility is enhanced when Uranus’ equatorial regions align face-on to our perspective. For instance, in 1986, Uranus’ south pole faced Earth directly, offering a remarkable view of its equatorial regions. In contrast, by 2008, the south pole had rotated out of view, providing a better glimpse of the equatorial regions. Recently, Uranus’ north pole has become increasingly prominent, with high-resolution infra-red filtered images revealing its brightness. By 2021, the north pole is tilted roughly 54 degrees toward Earth, posing new challenges for observing or imaging the equatorial bands.

During this year’s opposition, Uranus’ north pole will be tilted about 54 degrees toward us. Recent sketches from August 3rd, 2021, captured through an unfiltered 415mm (16.3-inch) Dall–Kirkham telescope, showcase faint yet discernible equatorial banding on the edge of Uranus’ disc. Although the author’s original orientation has been altered for consistency, the sketches offer a tantalizing preview of what stargazers can expect to see.

By taking advantage of the upcoming opposition, amateur and professional astronomers alike will have an opportunity to witness the captivating beauty of Uranus. Its unusual axial tilt and changing perspectives offer a unique and ever-changing spectacle in the night sky. As researchers continue to investigate and analyze this fascinating ice-giant planet, each observation brings us closer to unraveling the mysteries of Uranus and the wonders of our vast universe.

Image source: Luigi Morrone (top image), Damian Peach (middle image), D.Peach/Chilescope (bottom image), Greg Smye-Rumsby (graphics)