466 



KNOWLEDGE & SCIENTIFIC NEWS. 



[June, 1906. 



The Face of the Sky for June. 



By W. Shackleton, I'.K.A.S. 



This Sun. — On the ist the Sun rises at 3.51 and sets at 

 8.4 ; on the 30th he rises at 3.4S and .sets at 8.1 8. 



Summer commences on the 22nd, when the Sun enters 

 the sign of Cancer at 9 a.m. ; this is the longest day, 

 the Sun being 16^ 34" above the horizon. The equation 

 of time is negligible on the 1 5th, hence this is a convenient 

 day for adjusting sundials, as only the correction for 

 longitude is needed. Sunspots and prominences appear 

 to be slightly on the wane, but at this period of solar 

 activity the disc is rarely devoid of spots. 



The position of the Sun's axis, equator, and helio- 

 graphic longitude of the centre of the disc is shown 

 in the following table : — 



OccuLTATioxs. — The following occultations are visible 

 at Greenwich before midnight : — 



The Planets. — Mercury (June i, R.A. 3'' 56™; 

 Dec. N. 19° 57'. June 30, R.A. 8'' 8"" ; Dec. N. 2i°'53') 

 is in superior conjunction with the sun on the 8th, and 

 hence the planet is unobservable. Towards the end of 

 the month the planet is an evening star in Gemini, and 

 may be observed immediately after sunset low down in 

 the N.W. ; on the 25th the plant sets at 9.40 p m. or 

 jh 20™ after the Sun. 



Venus (June i, K.A. 6^ 31m; Dec. N. 24" 44'; 

 June 30, R.A. 81j 59™; Dec. N. 19° 2') is an evening 

 star in Gemini, setting about 2 hours after the Sun 

 throughout the month. The planet is pretty bright and 

 should be looked for shortly after sunset, itwill be found 

 in that portion of the sky illuminated by the afterglow of 

 the setting Sun. 



The apparent diameter of the disc is i2"-5 and it 

 appeals gibbous, 0^84 being illuminated. 



On the evening of the 24th the planet will appear in 

 pro.ximity to the crescent Moon, Venus being 2|° to the 

 north. 



Mars (June i, K.A. 5'' 30™; Dec. N. 24° 3'. June 30, 

 R.A. 6'' 5411 ; Dec. N. 23" 49') is practically unobservable 

 as he sets very shortly after the Sun. 



Jupiter (June I, R..\. 5'' 2'" ; Dec. N. 22 ' 23' ; June 30, 

 R.A. 5'' 31"! ; Dec. N. 22° 56') is in conjunction with the 

 Sun on the loth, hence the planet is unobservable. 



Saturn (June i, R.A. 23'' 6™ ; Dec. S. 7° 44'. June 30, 

 R.A. 23'' 8™ ; Dec. S. 7° 39') is a morning star, rising 

 about midnight near the middle of the month. The 

 planet is at the stationary point on the 27th, after which 

 date he continues to describe a retrograde path in 

 Aquarius for the next four months. 



Uranus (June 15, R.A. iS*" 31™ ; Dec. S. 23" 35') rises 

 about 9 p.m. near the middle of the month, and is on the 

 meridian about i a.m. The planet is in opposition on 

 the 29th, but he is not well placed for observation as he 

 is situated low down in Sagittarius. 



Neptune (June 15, R.A. 6^ 41"^; Dec. N. 22° 14') is 

 out of range for observation, as early next month he is in 

 conjunction with the Sun. 



Meteor Showers: — 



Telescopic Objects: — 



Double Stars, &c. — Scorpii, XVI.i' o™, 5.19^33', 

 mags. 2-7, 5'2; separation i3"'i. 



f Lyra>, X\TII.h4i™, N. 39° 33', known as the " double- 

 double " star, can just be separated by the naked eye, 

 but with a pair of opera glasses it is readily divided into 

 two components fj and e^, mags. 4-4 and 4'8. Usinga3-in. 

 telescope and a power of about 120, each of these stars 

 can again be divided into pairs, 3"'2 and 2"-6 apart re- 

 spectively, each component being about magnitude 5*5. 



M 57 (Lyra), the " ring " nebula. This nebula is the 

 only annular nebula accessible to telescopes of about 3-in. 

 aperture, and even then requires good seeing. It is 

 easily found, being situated about s of the distance from 

 fi toy Lyrae. The usual appearance in a 3-in. telescope 

 is that of a rather large nebulous star, but it bears magni- 

 fication well, and its annular character can easily be made 

 out with a moderately high power. 



M 80 (Scorpio). A compact globular cluster half way 

 between " and ,i Scorpii ; looks like a nebula in small 

 telescopes. 



Temperature of the Hemispheres. 



The Southern Hemisphere as a whole is colder than the Northern 

 Hemisphere, and a new determination of the mean temperatures 

 has been made by M. Julius Hann in the Lehrhucli dir Metcorologie. 

 In Southern latitudes the annual temperature varies froms^deg. C. 

 in Lat. 5odeg. to 2odeg. below freezing in Lat. Sodeg. The mean 

 annual temperature of the Southern Hemisphere is 13-6 deg. C, 

 and ranges from 17-3 deg. in January to 10-3 deg. in July. In the 

 Northern Hemisphere the mean annual temperature is 15 2 deg. C, 

 and ranges from 8 deg. C. in January to 22-5 deg. C. in July. In 

 the higher latitudes the diflerences of temperature seem to be 

 accentuated in the direction of a general lower temperature for the 

 South. The mean annual diflerence of temperature between the 

 two Hemispheres is about 1-5 deg. C. 



