Seen, however, at her brightest and at her greatest elongation from the sun, her splendour scarcely exceeds that with which Jupiter shines when high above the southern horizon at midnight.
Jupiter's satellites may be seen with very low powers; indeed the outer ones have been seen with the naked eye, and all are visible in a good opera-glass.

Their dimensions relatively to the disc are shown in Plate 7.

Their greatest elongations are compared with the disc in the low-power view.
Jupiter's belts may also be well seen with moderate telescopic power.
The outer parts of his disc are perceptibly less bright than the centre.
More difficult of observation are the transits of the satellites and of their shadows.

Still the attentive observer can see the shadows with an aperture of two inches, and the satellites themselves with an aperture of three inches.
The minute at which the satellites enter on the disc, or pass off, is given in 'Dietrichsen's Almanac.' The 'Nautical Almanac' also gives the corresponding data for the shadows.
The eclipses of the satellites in Jupiter's shadow, and their occultations by his disc, are also given in 'Dietrichsen's Almanac.' In the inverting telescope the satellites move from right to left in the nearer parts of their orbit, and therefore transit Jupiter's disc in that direction, and from left to right in the farther parts.

Also note that _before_ opposition, (i.) the shadows travel in front of the satellites in transiting the disc; (ii.) the satellites are eclipsed in Jupiter's _shadow_; (iii.) they reappear from behind his _disc_.