Our second planetary conquest this month lies closer to home and farther east along the ecliptic. The other ice giant, Uranus, is currently 1.9 billion miles (3.1 billion km) from Earth, residing within the borders of Aries the Ram. It reaches opposition Nov. 2, making now a great time to spot it. Even though it is two magnitudes brighter than Neptune, Uranus may prove more difficult to find because there are no distinctive star patterns nearby. But that’s okay. Half the fun is the thrill of the hunt.
As you can see from this issue’s Star Dome (page 34), Uranus is far removed from Aries’ four-star pattern. Therefore, it is probably best to start our quest from the hexagonal head of the Whale asterism in neighboring Cetus to the south. The head is comprised of Menkar (Alpha), Lambda (λ), Mu (μ), Xi2 (ξ2), Nu (ν), and Gamma (γ) Ceti. The pattern spans nearly 6° by 10°. Although that is too wide to squeeze into a single field, binoculars will come in very handy to spy the asterism from suburban and urban skies due to the dimness of its stars.
Menkar, the brightest of the bunch at magnitude 2.6, is a red giant star and so should put on a ruddy appearance through binoculars. It teams with blue-white 93 Ceti just 16' to its north to create an attractive binocular double star.
Aim toward Mu Ceti, the northernmost star in the head. Placing Mu toward the southern edge of the field of view will put 5th-magnitude 38 Arietis near the center. Moving 38 toward the southern edge will put 6th-magnitude Omicron (ο) Arietis near the center. You’ll notice Sigma (σ) Arietis just over 1.5° to its east and another greenish 6th-magnitude point about 1° to its west. That’s Uranus. Don’t confuse Uranus with 29 Arietis, which is about a degree farther west. All four points here — Omicron Arietis, Sigma Arietis, 29 Arietis, and Uranus — appear about the same brightness. But only Uranus will look green.
I would enjoy hearing from readers who spot either or both ice giants through their binoculars. Contact me through my website, philharrington.net. Until next month, remember that two eyes are better than one.