574 



KNOWLEDGE & SCIENTIFIC NEWS. 



[October, 1906. 



The Face of the Sky 

 for October. 



By A. Fowi.F.R, F.K.A.S., and 

 F.R.A S. 



\V. Shackleton", 



The Sun. — On the ist the Sun rises at 6.0 and sets at 

 5.39; on the 31st he rises at 6.52 and sets at 4.36. 



The position of the Sun's axis, centre of the disc, and 

 heliographic longitude of the centre are given in the 

 following table : — 



The Moon :— 



OccuLTATioNS. — The following table gives particulars 

 of the principal occultations visible before midnight at 

 Greenwich, during the month : — 



The Planets. — Mercury (Oct. i, R.A. 12'' 49""; 

 Dec. S. 4° 24' ; Oct. 31, R.A. 15I' 42™ ; Dec. S. 22° 7') 

 is an evening star throughout the month, but sets so 

 soon after the Sun that he may be considered un- 

 observable. 



Venus (Oct. i, R.A. 15I1 19m; Dec. S. 22° 32' ; 

 Oct. 31, R.A. 16'' 44'"; Dec. S. 27 48') remains 

 an evening star, but, in consequence of the great 

 southerly declination can only be observed for a short 

 time after sunset ; the planet in fact sets about one 

 hour after the sun throughout the month. The distance 

 of the planet from the earth is rapidly diminishing, and 

 the apparent diameter accordingly increases from 28"-4 



on the ist to 44"-8 on the 31st. The crescent phase is 

 now presented to the observer, one-third of the disc 

 being illuminated on the 15th. The greatest brilliancy 

 of the planet as seen from the earth occurs on the 

 26th. 



Mars (Oct. i, R.A. 10" 55™; Dec. N. 8" 11'; Oct. 31, 

 R.A. 12'' 5""; Dec. N.0'47') is a morning star rising 

 about 3.30 a.m. throughout the month. With its small 

 apparent diameter of about 4", it is of little telescopic 

 interest. 



Jupiter (Oct. I, R.A. 61' 42'"; Dec. N. 22° 50'; Oct. 

 31, R.A. 6'' 48™ ; Dec. N. 22° 47') is coming into a 

 more favourable position for observation, rising at 



9.50 p.m. on the ist, and at 7.58 p.m. on the 31st. The 

 planet describes a short direct path between f and i 

 Geminorum until the 29th, when he is " stationary." 

 The apparent diameter of the planet increases from 

 36"-o to 39"'4 during the tnonth. 



Saturn (Oct. i, R.A. 22'' 48""; Dec. 8.9° 51'; Oct. 31, 

 R.A. 22I1 43m ; Dec. S. 10'' 18') is favourably placed for 

 observation in the evening, being on the meridian at 

 10.9 p.m. on the ist, and at 8.7 p.m. on the 31st. The 

 planet describes a short retrograde path a little to the 

 South of ^ Aquarii. The outer major and minor axes 

 of the ring system are respectively 43" and 4"-6, so that 

 in small telescopes the ring appears almost as a straight 

 line ; the " disappearance " of the ring is due next year. 



Uranus (Oct. 15, R-.-X. 18'' 21""; Dec. S. 23 41'), 

 remains in Sagittarius, but is not very favourably 

 situated for observation, as it sets soon after 9 p.m. at 

 the beginning of the month, and at about 7.30 p.m. at 

 the end of the month. 



Neptune (Oct. 15, R.A. 6" 55"; Dec. N. 21" 57'), rises 

 shortly after 9 p.m. and crosses the meridian at 5.19 a.m. 

 at the middle of the month. The planet is about li 

 degrees Xorth-West of ;- Geminorum, is in quadrature 

 on the 6th, and stationary on the i6th. 



Meteors. — The principal meteor showers during the 

 month is that having its radiant point near ■' Orionis, 

 and hence known as the Orionids. The maximum is 

 from the i8th to the 20th, and the meteors are described 

 as swift with streaks. The radiant point is in R.A. 92° 

 Dec. N. 15°. 



Algol presents conveniently observable minima on 

 the 3rd at 9.19 p.m., 23rd at 11.2 p.m., and 26th at 



7.51 p.m. 



Telescopic Objects: — 



Double stars: 7 Arietis i'' 48'^, N. 18' 48', mags. 

 4-2, 4-4 ; separation 8"-8. Easy double, power 30 : 

 notable as being the first double star observed tele- 

 scopically. 



y Andromedte i'' 58"", N. 41° 51', mags. 2-i, 4-9, sepa- 

 ration io"-2. The brighter component is intensely 

 yellow, whilst the other is greenish blue. The fainter 

 star is remarkable for being a binary, the components of 

 which are now less than i" apart. 



Xebul.4s : — 



Nebula in Andromeda, easily visible to the naked eye, 

 and readily found by referring to the stars S and v Andro- 

 medae. Seen with a 3 or 4 inch telescope, it appears to 

 be an extended oval, which is in reality composed of 

 spiral streams of nebulous matter. 



(32 M.) Nebula close to the great Andromeda 

 nebula, and situated about 2 ' to the South. It is fairly 

 round, and appears somewhat like a star out of focus. 



(18 i§.) Lies about the same distance north of the great 

 Andromeda nebula that 32 M does south ; it is faint, but 

 large and elliptical. 



