October 28, All Night
Uranus is at opposition, which means it’s at its brightest and closest to us for the year. A telescope will reveal a pale cyan-grey disc some 3.74 arc minutes in diameter. With the naked eye, you may be able to spot magnitude +5.7 Uranus in Aries below Gamma Arietis (Mesarthim) and west of 19 Arietis. You’ll need a very dark and clear sky. Sharp-eyed observers long ago could have discerned this faint “wandering star” moving against the background stars by a few degrees per year, but they never recorded their observations of the seventh planet.
Asteroid 9 Metis, just two days past opposition, is in the same region of the sky this week. Look for it between Gamma Ceti (Kaffaljidhma) and Alpha Piscium (Alrescha) this week. Metis is a good target for telescopes. It’s just 1.17 AU distant from us, but its 200-kilometre diameter means we see it as a speck of visual magnitude +8.5.
October 27 to November 2
Sunlike star Tau Ceti sits near the horizon almost directly southeast at 10 p.m. Much like our own solar system, Tau has a retinue of possibly several planets and a dust disk. As a type G8V star, however, Tau is about three-quarters our Sun’s mass, about half its brightness and has a little more gold tinge to it. Tau is really close as stars go—only 11.9 light years from Earth.
Eta Cassiopeiae is another naked-eye, sun-like star high in the sky to north during mid-autumn evenings. Look for a modest star just left of the right-side \/ point in Cassiopeia’s \/\/. (Got that?) At 19 light years away, Achird is a little more distant than Tau Ceti. It’s also slightly bigger, hotter, brighter and whiter than our own G2V sun. Compare its colour to Tau Ceti. Achird is also a fine double star in a telescope.
These solar-like stars suggest to us how our Sun looks from just a few light years away: an unremarkable point of white light. What’s remarkable is how we are here—and how we are able to consider what our own star looks like in an alien night sky!
