"We were taking an image of Himalia to test the instrument.
Because the structure appears so close to Himalia, it may be the result of an impact that blasted material off the 170-kilometre-wide moon, suggested Cheng and colleagues in a study presented at the Lunar and Planetary Science Conference in Houston, Texas, earlier this month.
Over the years, I've also observed Uranus's challenging moon Miranda and Jupiter's challenging moon Himalia in the very dark skies of the Okie-Tex Star Party.
Jupiter's VI moon, Himalia, was my next target after I failed on several attempts to find the planet's V moon, Amalthea.
The next easiest (if that's the word) is tiny Himalia, which strays as far as 1[degrees] from Jupiter but is always hard to pick out among the many 14th- and 15th-magnitude background stars.
For wide-ranging, slow-moving satellites like Jupiter's Himalia and Saturn's Phoebe, actual plotted tracks are appropriate.
Whitman managed to track down Jupiter's moon Himalia with his 16-inch Meade Newtonian reflector.
Because it roams as far as 1[degrees] from Jupiter itself, tiny Himalia is hard to tell from countless 14th- and 15th-magnitude background stars.
For example, among Jupiter's family of 16 moons is the little satellite Himalia
. This 185-kilometer-diameter world is difficult to pick out as it shines at a meager magnitude 14.6.
Much farther afield is tiny Himalia
. It ranges so far from Jupiter -- 11 million kilometers -- that an astronaut, after landing on one of Jupiter's bigger moons, would still need a telescope to see Himalia
moons Metis 60 x 34 km Adrastea 20 x 14 km Amalthea 250 x 128 km Thebe 116 x 84 km Io 3,642 km Europa 3,130 km Ganymede 5,268 km Callisto 4,806 km Leda 10 km Himalia
170 km Lysithea 24 km Elara 80 km Ananke 20 km Carme 30 km Pasiphae 36 km Sinope 28 km
. Having seen Mars's moons Phobos and Deimos in 1990, Rob Johnson of Liverpool, England, wondered how difficult it would be to observe or photograph other faint planetary satellites.