THE FACE OF THE SKY FOR SEPTEMBER. 



Bv W. SH.\CKLETOX. F.R.A.S.. A.K.C.S. 



The Sun. — On the 1st the Sun rises at 5.13 and sets at 6.47 ; 

 on the 30th he rises at 5.59 and sets at 5.41. The Sim enters 

 the sign of Libra on the 23rd at 10 p.m., when autumn 

 commences. The equation of time is negligible on the 1st 

 and 2nd, hence these dates are convenient for the adjust- 

 ment of sun-dials, as only the longitude correction is needed. 

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

 heliographic longitude of the centre are given in the following 

 table :— 



The Moon :- 



OccULT.\TlONS. — The following are the particulars of the 

 occultations of the brighter stars visible from Greenwich. 

 The bright star Scorpii is occulted just before sunset, but 

 in consequence of the brightness of the star the phenomenon 

 can be observed with telescopes of about four inches aperture : — 



The Pl.anets. — Mercury (September 1st. R..-\. 12'' 15™; 

 Dec. S. 4° 25'. October 1st, R.A. ll'' 49"; Dec. N.0° 5') is an 

 evening star in Virgo during the early part of the month, and 

 sets at 7.10 p.m. on the 3rd. The planet is, however, not well 

 placed for observation. 



On the 26th, Mercury is again in inferior conjunction with 

 the Sun. 



Venus (September 1st, R.A. 9" 15'"; Dec. N. 16" 43'. 



October 1st. R.A. ll" 37"" ; Dec. N. 4° 2 ) is a morning star in 

 Leo. very little observable, as she rises in the N.E. on the 1st 

 at 3 a.m., and on the 31st at 4.30 a.m. The apparent 

 diameter is diminishing, being now about 10 , whilst 0'96 of 

 the disc is illuminated, thus the planet appears nearly at the 

 ■' full " phase when seen in the telescope. 



Mars (September 1st, R.A. ll" 



13" 



Dec. X. 6° 6'. 



October 1st, R.A. 12" 24" 



Dec. S. 1" 43') is inobserxable, 



being in conjunction with the Sun on the 27th. 



Jupiter (September 1st, R.A. \2^ 57™: Dec. S. 4° 51'. 

 October 1st. R.A. 13" 20'°; Dec. S. T 14') is .getting more to 

 the West, and at the end of September the planet will be too 

 low down in the West at sunset to be observed. On the 15th 

 the planet sets at 7 p.m. 



No satellite phenomenon is observable this month, as the 

 planet is situated in too bright a portion of the sky. The 

 Moon appears near the planet on the evening of the 5th. 



Saturn (September 1st. R.A. 2" 20™; Dec. X. 11° ll') 

 October 1st, R.A. 2" 15"; Dec. N. 10° 39'' is a conspicuous 

 object in the evening sUy looking East, and is situated about 

 10° South of « and p .-^rietis. The planet may readily be 

 distinguished from other planets by his leaden hue. and, 

 although a bright object, his brilliancy lacks the sparkling 

 qualities of the other bright planets. 



On the 1st September the planet rises at S.37 p.m., and on 

 the 1st October at 6.46 p.m.. remaining visible throughout the 

 night, the planet is thus well placed for observation. The 

 apparent diameter of the ball is 18", whilst the diameters of 

 the major and minor axes of the outer ring are 45" and 14" 

 respectively ; thus, as seen in the telescope, the ring appears 

 well open, being inclined to our line of \ision at an angle of 

 18°, the Southern surface being visible. 



Saturn is one of the easiest of objects to observe in the 

 telescope, as usuall\- good seeing can be obtained with this 

 planet on poor nights sufficient to spoil all definition on other 

 objects. 



In a three-inch telescope the ring should be visible with a 

 magnifying power of about fifty, and the belts on the planet's 

 surface with a power of about eighty. 



The Moon appears near the planet on the evening of the 

 21st, Saturn being one and a half degrees to the South, 



Uranus (September 15th, R.A. 19" 11'^; Dec. S. 22° 16'), 

 though rather low down in the sky, is fairly well placed for 

 observation during the early evening, and is due South 

 shortlv after dusk. The planet is situated in Sagittarius in a 

 part of the sky devoid of good reference stars, though the 

 4th magnitude double star /; Sagittarii is about 2° to the 

 South. The planet is at the stationary point on the 1st 

 October, after which his motion is direct or Easterly. 



Uranus can just be discerned with the naked eye on clear 

 nights, but the slightest optical aid is sufficient to make the 

 planet clearly visible. 



Xeptune (September 15th. R.A. 7" 31"; Dec. X 21° lO') 

 rises about midnight near the middle of the month, and hence 

 is not in a favourable position for ob.serxation. The planet is 



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