June 1, 1891.] 



KNOWLEDGE. 



117 



the radiant point is below tlie horizon or near the horizon 

 at the usual hours of observation ; and as Mr. Denning 

 tells us that he made nearly all his observations looking 

 East, meteors from radiants in the West would naturally 

 be passed over. Further, I do not think that where the 

 radiant is of this long-enduring or stationary character, 

 the shower is of uniform intensity throughout. On the 

 contrary, so far as I have traced, the maximum of each 

 long enduring shower occurs nearly at the same date in 

 successive years. The showers appear, moreover, to be 

 more intense in some years than in others. 



I wish to state iu conclusion, that I never disputed in any 

 way the accuracy of Mr. Denning's observations. I only 

 dilfer from him as to the classification and arrangement of 

 some of them. 



Truly yours, 

 10, Earlsfort Terrace, Dublin. W. H. S. Monck. 



THE FACE OF THE SKY FOR JUNE. 



By Herbert Sadler, F.R.A.S. 



THE increase in solar activity still continues. During 

 June there is no real night in the British Islands. 

 There will be an annular eclipse of the Sun on 

 the afternoon of the Gth, which will be visible as a 

 partial eclipse at Greenwich. At that station the 

 eclipse begins at 5h. 2.2m. p.m., the first contact taking 

 place at an angle of 88° from the vertex towards the west, 

 reckoning for direct image ; the middle of the eclipse being 

 at 5h. 'l(5'7m. r.ai. ; and the last contact taking place at 

 Gh. 23'()in. P.M., at an angle of 5° from the vertex towards 

 the west ; the magnitude of the eclipse being 0-2IJ8. Witli 

 the exception of an exceedingly small eclipse on the morn- 

 ing of March 2Cth, 1895, the next solar eclipse visible at 

 Greenwich will not take place till June 8th, 1899. 



The following are conveniently ol).servable times of 

 minima of some Algol type variables (c/. " Face of the 

 Sky " for April and May) : U Cephei. — June 2nd, lOh. 

 29m. P.M. ; June 7th, lUh. 9m. p.m. ; June 12th, 9h. 49m. 

 P.M. ; June 17th, 9h. 28m. p.m. ; June 22nd, 9li. 8m. p.m. 

 S Cancri. — hme 11th, lOh. 22ui. p.m. 8 Libra\ — June 

 14th, Oh. 2Cm. a.m.; June iHth, midnight; June 27th, 

 llh. H.'im. P.M. U Coronie. — June 20tli, llh. 49m. p.m. ; 

 June 27th, 9h. 31m. p.m. U Ophiuchi (17h. 10m. 57s. -f 

 1° 20').— Max., G-0 mag. ; min., G-7 uuig. ; period, Od. 20h. 

 7m. 41-60s.— June 4th, lOh. 17m. p.m. ; June 9th, llh. 

 3m. P.M. ; Jime 14th, llh. 48m. p.m. ; June 15th, 7h. 5Gm. 

 P.M. ; June 20th, 8h. 41m. p.m. ; Jime 25th, 9h. 28m. p.m. 

 Y Cygni (20h. 47m. 47s. 4-34° 15').— Max., 7-1 mag.; 

 min., 79 mag. ; period, Id. lib. 5Gm. 48s. — June 2nd, 

 lOh. Gm. P.M. ; June 5th, lOli. Im. p.m. ; June 8th, 9li. 

 5Gm. P.M. ; June 11th, 9h. 51m. p.m. ; June 14th, 9h. 45m. 

 P.M. ; June 17th, 9h. 40m. p.m. ; June 20th, 9h. 34m. p.m. ; 

 June 23rd, 9h. 28m. p.m. ; June 2Gth, 9h. 23m. p.m. ; June 

 29th, 91i. 18ni. P.M. Variable, of short period, not of Algol 

 type. t; AquiliB (19h. 4Gm. 52s. + 0" 43). Max., 3-5 

 mag. ; min., 3-7 mag. ; period, 7d. 4h. 14m. Os. June 

 27th, 9h. P.M. Maximum of R Hydra) (rf. " Face of the 

 Sky " for February, 1889) on June 1st. The lines of 

 hydrogen in the spectrum of this star appear bright near 

 maxinuuu. 



Mercury is a morning star throughout June, but owing 

 to his proximity to the Sun and the strong twilight pre- 

 vailing he is not very favourably situated for observation. 

 He rises on the 1st at 3h. 13iii. a.m., or 38m. before the 

 Sun, with a northern declination of 13' 2G' and an apparent 

 diameter of 84", just three-tenths of the disc being illumi- 



nated. On the 16th he rises at 2h. 48m. a.m., or 56m. 

 before aimrise, with a northern declination of 18° 53', 

 and an apparent diameter of 6|", six-tenths of the disc 

 being then illuminated. On the 30th he rises at 3h. 9m. 

 A.M., or 38m. before the Sun, with a northern declination 

 of 23° 54'. and an apparent diameter of 5j-", yy^j of the 

 disc being then illuminated. He is at his greatest western 

 elongation (23|'^) on the evening of the 5th. During the 

 month he passes from Aries throughout the whole length 

 of Taurus into Gemini, but without approaching any con- 

 spicuous star very closely. Venus is also a morning star 

 this month, but her observation is rendered difficult by the 

 same conditions which militate against the visibility of 

 Mercury. She rises on the 1st at 2h. 45m. a.m., or lb. 6m. 

 before sunrise, with a northern declination of 13° 47' and 

 an apparent diameter of ll.V", /..'o of the disc being illumi- 

 nated. On the 30th Venus rises at 2h. 24m. a.m., or 

 Ih. 23m. before the Sun, with a northern declination of 

 22° 1' and an apparent diameter of lOV', ^Vif o( the disc 

 being then illuminated, and the brightness of the planet 

 being only one quarter of what it was on January 8th. 

 During the month she passes from Aries into Taurus. 

 Mars is invisible. 



The minor planet Vesta (<;/'. " Face of the Sky " for 

 January, 1890) comes into opposition on the 23rd, and but 

 for her great southern declination would be excellently 

 placed for observation, as, with one exception, this is the 

 closest approach to the earth that she has made during the 

 last thirty years. Her distance from us at opposition is 

 about lOG, 655,000 miles, and she is visible to the naked 

 eye during the whole of June, though the proximity of the 

 nearly full Moon at the actual date of opposition will 

 interfere with naked eye observation. At the present 

 opposition she attains to the 6*0 magnitude, and it is to be 

 hoped that search will be made with powerful telescopes 

 in the South of l*;urope and the I'nited States, both by 

 means of photography and by eye observations, for a pos- 

 sible satellite. On the day of opposition she souths at 

 midnight with a southern declination of 20^ , her apparent 

 diameter being about 1 J". A map of the path during the 

 month will be found in the KinjUsli MirlHinir for May 8th. 

 As Jupiter does not rise till llh. 9m. p.m. on the last day of 

 the mouth, and as none of the satellite phenomena are 

 visible at Greenwich till' after midnight, we defer an 

 ephemesis of him till July. Saturn is an evening star, but 

 is nearing the west so rapidly that he should be looked for 

 as soon as possible after sunset. He sets on the 1st at 

 3h. 9ni. a.m., with a northern declination of 9^ 27' and an 

 apparent ecjuatorial diameter of 174' (the major axis of the 

 rmg-system being 40|" in diameter, and the minor 3|"). 

 On the 30th he sets at llh. 13m. p.m. with a northerly 

 declination of H^y, and an apparent equatorial diameter of 

 IG'G" (the major axis of tlie ring-system being 38j" iu 

 diameter and the minor 3"). On the 4th lapetus is near 

 his greatest eastern elongation, where he is faintest. On 

 the evening of the Gth Titan is eclipsed by the shadow of 

 Saturn, the middle of the eclipse taking place about 7h. 30m. 

 P.M., and the satellite is again eclipsed on the evening of 

 the 22nd, the middle of the eclipse being at about Gh. 45m. 

 P.M. lapetus is about 3G" north of Saturn on the evening 

 of the 23rd. Saturn is in quadrature with the Sun on the 

 1st, and describes a short direct path in Leo during June, 

 but does not approach any conspicuous star. Uranus rises 

 on the 1st at 3h. 52m. p.m., with a southern declination of 

 10° 11' and an apparent diameter of 3-0". On the .SOth 

 he ri.ses at Ih. 55m. p.m., with a southern declination of 

 10° r, and an apparent diameter of 3-G". He describes a 

 very short retrograde path to the N.N.E. of 86 Virginia 

 during the month. Neptune is invisible. 



