Nov. 23, 1883.] 



♦ KNOWLEDGE ♦ 



319 



will rise an hour sooner. Hence, about midnight he is well up in 

 the sky, in which he is now by far the most brilliant and con- 

 spicuous object. He remains in Cancer. The phenomena of his 

 Satellites visible before 1 a.m. during the next fortnight are : — 

 First, the egress of the shadow of Satellite I., to-night (23rd), at 

 lOh. 38m.; followed by that of Satellite I. itself at llh. 47m. 

 Then, on Nov. 25, Satellite IV. will re-appear from ocoultation 

 behind Jnpiter at 12h. 38m. p.m. On the 20th, the shadow of 

 Satellite III. will euter on to Jupiter's face at lOh. 40ra. p.m. 

 At 12h. 5t!ni. 493. on the 29th, Satellite I. will disappear in eclipse. 

 On November 30, the ingress of the shadow of Satellite I. will 

 happen at lOh. 12ra. p.m., followed by that of the Satellite casting 

 it at llh. IGm. The shadow will pass off the disc of the planet 

 at 12h. 32m., the Satellite not until the next morning. On the 

 night of December 1, Satellite I. will reappear from occnltation 

 at lOh. 45m. ; and Satellite II. disappear in eclipse at llh. 

 32m. 27s. On December 3, the shadow of Satellite IV. will leave 

 Jupiter's face at lOh. Om., and forty-three minutes later Satellite II. 

 will also pass off the planet's disc. Satellite III. will reappear 

 from occultationat llh. 58m. p.m. on the 7th, and six minutes after 

 midnight the shadow of Satellite I. will begin its transit over 

 Jupiter. Saturn is visible all night long, and is excellently placed 

 for the observer. No more wonderful or interesting telescopic 

 object than this planet exists in the heavens. Uranus is still 

 invisible. Neptune is visible all night long with sufficient optical 

 aid, and is travelling to the south of o Arietis (" The Stars 

 in their Seasons," Map XII). Pons's Comet, to which re- 

 ference was made on p. 292, will during the next fortnight 

 travel in an easterly and somewhat southerly direction, through 

 that very blank region of the sky to the extreme north-west 

 of the constellation Lyra. The moon is 23'5 days old to- 

 day at noon; and, of course, 29'5 days at the same time 

 on the 29th. Then at noon on the 30th she will be 07 

 days old, and 7'7 days old at mid-day on December 7. Hence 

 she will scarcely be visible for the observer's purpose before 

 December 3. No occultations of stars occur during the next four- 

 teen days. At fonr o'clock this afternoon the Moon will leave Leo 

 for Virgo ; through which constellation she will continue to travel 

 until 4 a.m. on November 27, when she passes into Libra. Her 

 passage through Libra occupies until three o'clock in the morning 

 of the 2yth, at which time she enters the northera strip of Scorpio. 

 She takes thirteen hours to cross this, and at 4 p.m. of the same 

 day emerges in the southern part of Ophiuchus. Here she continues 

 nntil 5 a.m. on December 1, when she crosses into Sagittarius. She 

 does not quit Sagittarius for the northern part of Capricornus until 

 midnight on December 3, and at five o'clock the next afternoon 

 travels into Aquarius. Here she remains until 10 a.m. on Decem- 

 ber 7, when she enters Pisces. We there leave her. 



SATURN IN A THREE-INCH 

 TELESCOPE. 



By a Fellow of tue Royal Astroxo.mical Society. 



INASMUCH as it has been represented to us that our 

 notices on pp. 313, 221, and 220 respectively of 

 Vol. I. of the planets Mars, Jupiter, and Saturn, as seen 

 : .'! inch telescope, were of too ourt and merely 

 incidental a character, and that somewhat fuller informa- 

 tion is needed as to the aspect of these planets in such an 

 instrument as that whose use we are presupposing; we now 

 purpose to enter, in three separate papers, rather more into 

 detail of the phenomena which they present in a 3-inch 

 telescope, and to give the necessary information concern- 

 ing all that the student may reasonably expect to see of 

 them with it. 



Coming as Saturn does into opposition to the sun during 

 the early morning of November 29th, with his rings nearly 

 at their greatest opening, and southing in this country at 

 an altitude of between W and 60°, the planet could hardly 

 be in a more favourable position for the observer than he 

 is at present. lie will be found in the sky just now to th« 

 north and west of AUlebaran (''The Stars in their Seasons," 

 Map 1.), and will be instantly identified by the leaden hue 

 of his light as contrasted with the red colour of " The 



Bull's Eye." The suVyoined sketch of the planet was made 

 at the telescope with a power of 204 on the night of 

 November 13th, at llh. -tSm. p.m. 



Saturn, 1883, Nov. 13, llh. 45m. G.JI.T., power 201-. 



The flattened figure of the planet will at once strike the 

 observer's eye. In other words, he will note that instead 

 of presenting a circular disc, the outline of Saturn is very 

 perceptibly elliptical — or, as it is commonly called, " oval " 

 — the longest diameter of the ellipse being in the direction 

 of his equator. Technically, his figure would be described 

 as an oblate spheroid, which, put into plain English, means 

 that instead of the planet being a perfect sphere, he is, as 

 it were, turnip-shaped, i.e., flattened at the poles and 

 bulged out at the equator. This eflect of the rapid 

 rotation of Saturn needs no further mention here. The 

 southern part of the globe (that which is uppermost in the 

 telescope) will be seen to be covered by a perceptible 

 dark shading, which, however, terminates with a well- 

 defined edge not far from the planet's equator. Below 

 (north) of this is a bright equatorial band. The general 

 yellow tint of the ball is also a notable feature. Where 

 the ring crosses Saturn's disc a broad line of shading will 

 be observed, and a careful and attentive study of this 

 under good definition will show that it consists of two 

 parts, a dark, broad line of shading crossing, as we have 

 said, the face of the planet ; and seemingly superposed 

 upon it, and in contact with the inner edge of the 

 ring, a very narrow black line. This latter is the 

 real shadow of the ring upon the planet. The broader 

 stripe is a part of the strange interior dusky or " crape " 

 ring, of which we are to speak immediately. If we turn 

 now to the ring itself, we shall perceive that it really con- 

 sists of two concentric ones, the inner one being very much 

 broader, and notably brighter than the outer one, or than 

 the dusky capping on the southern hemisphere of the 

 planet. A narrow dark line will be seen to separate the 

 inner ring from the outer one. In telescopes of 4 inches of 

 aperture and upwards this dark division is traceable right 

 round the ring. With a 3 inch telescope it will, under 

 favourable circumstances, be well seen in the " Ansiv " 

 (the ea.stern and western portions of the ring), but will 

 scarcely be fairly discernible entirely round. At moments 

 of the best definition the shadow of Saturn will be seen, 

 as drawn above, projected on the inner ring only, the 

 black line, known from its discoverer as " Cassini's 

 Division," at once bounding it and the planet's south 

 pole on the south. The " crape " ring to which reference 

 has previously been made is jtist beyond the power of our 

 instrument. On nights when atmospheric conditions admit, 

 however, of the use of a high power, faint indications of 

 it may be seen in the form of a seeming ill-defined shading 

 away of tlie inner edge of the broad interior ring, in the 

 Ansa\ No connection, though, is traceable between this 

 and that jiortion of the dark ring which is seen crossing 

 Saturn's disc ; albeit in larger instruments the whole 



