22 



KNOWLEDGE & SCIENTIFIC NEWS. 



[Jan., 1905. 



The Face of the Sky for January. 



By W. Shackleton, F.R.A.S. 



The Sun. — On the ist the Sun rises at 8.S, and sets 

 at 4.0 ; on the 31st he rises at 7.42, and sets at 4.45. 



The earth is nearest the Sun on the ist at 5 a.m., hence 

 he attains his ma.ximum apparent diameter of 32' 35". 



Sunspots, facula;, and prominences are very numerous ; 

 at the time of writing there are several fine groups of 

 spots almost stretching from limb to limb, which define 

 the spot zone most conspicuously. 



For plotting the positions of spots, &.C., the following 

 table may be used : — 



OccuLTATioNS. — The following occultations of the 

 brighter stars are visible at Greenwich. 



The Planets :— Mercury.— Towards the end of the 

 month Mercury is a morning star in Sagittarius, being 

 at greatest elongation of 24=' 28' W. on the 22nd, when 

 he rises at 6.24 a.m. 



\'enus is the most conspicuous object in the evening 

 sky looking towards the S.W., and sets about 4 hours 

 after the sun. The planet is increasing in brilliancy, and 

 can readily be seen when on the meridian in broad day- 

 light ; the time of meridian passage is 3.5 p.m. and is 

 very nearly the same on each day of the month, whilst 

 the meridian altitude increases from 23 on the ist to 37^' 

 on the 31st. The apparent diameter of the planet on 

 the ijtii is i'i"-2 ; the disc appears slightly gibbous, 0-65 

 being illuminated. 



.Mars does not rise until after midnight. 



Jupiter is on the meridian shortly after sunset, and 

 remains above the horizon until midnight. In conse- 

 quence of increasing distance from the earth, the planet 

 is diminishing in lustre; the apparent equatorial diameter 

 is 4o"-5 on the i6th, whilst the polar diameter is 2"-6 

 smaller. The planet is in quadrature on the 12th. 



The following table gives the phenomena of the satel- 

 lites visible in this country. 



'* Oc. D." denotes the disappearance of the Sitellile behind the disc, and 

 "Oc. R." its re-appearance; "Tr. I." the ingress of a transit across the disc, 

 and "Tr. li." its egress; " Sh. I." the ingress of a transit of the shadow across 

 the disc, and " Sh. E." its egress. 



Saturn is diminishing in brightness, and is only observ- 

 able for a short time in the S.W. after sunset. The plane 

 of the ring is inclined to our line of vision at an angle of 

 14''; hence the ring appears well open. 



Uranus is unobservable. 



Neptune souths at 1 1.45 p.m. on the ist and at 9.44 on 

 the 31st. He is situated in the constellation Gemini and 

 can readily be found by reference to m Geminorum. 



Right Ascension. N. Declination. 



Neptune (Jan 14) . 6*^ 27"" 19^ .. 22° 16' 33" 



M Geminorum . . 6'' 17"' 13^ . . 22° 33' 36" 



Meteor Showers : — 



Jan. 2-3 XV.Ii2o"i| + 53 Quadrantids 



,, 17 IxiX.h 4ml + 53 I OCygnids 



Swift ; long paths. 

 Slow ; bright. 



The Stars : — 



Minima of Algol occur between sunsetj and midnight 

 on the 13th at 10.37 p.m., i6th at 7.26 p.m., and 19th at 

 4.14 p.m. 



Ceti (Mira) should be watched, as it will probably 

 reach a ma.\imum next month, when observation will be 

 difficult on account of daylight. 



Telescopic Objects: — 



Nebula;. - -Orion Nebula, situated in the sword of 

 Orion, and surrounding the multiple star ", is the finest 

 of all nebuhi-; with a 3 or 4 inch telescope, it is best 

 observed when low powers are employed. 



Crab Nebula (M i), in Taurus, situated about lA^ 

 north-west of f Tauri in R.A. 5h. 29m., Dec. 21" 58' N. 



Clusters. — M 37, situated in .\uriga, is one of the 

 finest clusters, and very compact ; its position is R.A. 

 5h. 46m., Dec. 32" 32' N. 



Double Stars. — P Orionis (Rigel), mags, i and 9. sepa- 

 ration 9". f)n account of the brightness of the principal 

 star, this double is a fair test for a good object-glass of 

 about 3-inch aperture. 



S Orionis, mags. 2 and 7, separation 53" ; easy double. 



f Orionis, triple, mags. 3,6, and 10, separation 2"-5 and 

 56" ; rather difficult in a 3-inch telescope. 



^ Orionis, mags. 4 and 6, separation 4"-5 : pretty 

 doulile. 



" Orionis, triple, mags. 4, 8, and 7, separation i2"-5and 

 42." 



