224 



KNOWLEDGE. 



June, 1911. 



:he 21st. at 1 a.m. the Moon is in conjunction with the planet, 

 Mars being only 0' 12' to the nofth isec I^iKure 1). 



Jupiter: — 



Saturn 



Jupiter is a brilliant object in the evenini; sky looking South, 

 and is in the very best position for observation. Near the 

 middle of the month the planet is on the meridian at 8.45 p.m., 

 but observations m.ay commence as soon as it is dark, since he 

 is above the horizon at Sunset. 



The planet is describing a retrograde path near a V'irginis 

 and is at the stationary point on July 3rd. 



The most noticeable features as seen in the telescope are 

 the moons, the dark belts, and the polar flattening ; this latter 

 is shown by the equatorial diameter being 41"- 6 and the polar 

 diameter 2"- 7 less. If sufficient magnifying power be used 

 with a telescope of about four inches aperture, markings and 

 also the " Great Red Spot " on the belts may be observed, 

 from which the period of rotation may be deduced. This is 

 only Q'" 53'". which explains the cause of the obl.iteness of the 

 planet. 



The following table gives the satellite phenomena visible 

 before midnight : — 



"Oc. D." denotes the disappearance of the Satellite behind the disc, and 

 " Oc. R-"_its reappearance: " Tr. I." the ingress of a transit across the disc, and 

 " Tr. E." its egress ; " Sh. I." the ingress of a transit of the shadow across the disc, 

 and "Sh. E." its egress; " Ec. D." denotes disappearance of Satellite by Eclipse, 

 and " Ec. R." its reappearance. 



The configurations of the satellites as seen in an inverting 

 telescope and observing at 11 p.m. are as follows: — 



The circle (O) represents Jupiter; O signifies that the 

 Satellite is on the disc ; • signifies that the Satellite is 

 behind the disc, or in the shadow. The numbers are the 

 numbers of the Satellites. 



Saturn is a morning star in Aries, rising E.N.E., about 

 3 a.m.. on the 1st June, and at 1.7 a.m. on the 30th. In con- 

 sequence of the planet being in a bright portion of the sky he 

 is, for all practical purposes, unobservable. 



Ur.ANUS : — 



Uranus rises in the S.E. at 11.20 p.m. on the 1st, and at 

 9.23 p.m. on the 30th. The planet is unfavourably placed for 

 observation, as he is low down in the sky ; he is describing a 

 retrograde, or westerly, path, about 2° S.E. of f Capricorni ; 

 he can just be discerned with the naked eye on a very clear 

 night, but is easily visible through a pair of opera glasses. 



Neptuxe : — 



Neptune is practically unobservable as he sets at 11 p.m., 

 on the 1st and at 9 p.m. on the 30th. 



Meteor Showers: — 



Mira lo Cetit is due at maximum on the 30th. but obser- 

 vations should be made before and after this date as the 

 period is somewhat variable. The magnitude at maximum is 

 usually about 3'0 but this, too, is variable. The spectrum at 

 maximum is a mixed one exhibiting both bright and dark lines. 



Telescopic Objects : — 



Double St.\rs, &c. — 7 Virginis .\II." 37'", S. 0" 54', mags. 

 3, 3, separation 6"-0. Fine doable for small telescopes with a 

 magnification of about 80. 



/i Scorpii, XVI." 0'", S. 19 34', m.ags. 27, 5'2 ; separation 

 13".l. 



e Lyrae, XVIII.'' 41'". N. 39° if, 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, 

 fi and f-i, mags. 4'4 and 4"8. Using a 3-in. telescope and a 

 power of about 120, each of these stars can again be divided 

 into pairs, 3"'2 and 2"'6 apart respectively, 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 tiien requires good seeing. It is easily found, being 

 situated about 3 of the distance from /^ to 7 Lyrae. The 

 usual appearance in a 3-in. telescope is that of a rather large 



