ASTRONOMICAL

Hokitika Guardian, 2 September 1929, Page 7

ASTRONOMICAL

SEPTEMBER 1929. The sun will enter the zodiacal sign Lebra on September 24th at 0.24 a.m., when the equinox occurs. The distance o*' tiie sun from the earth will then be about 93,260,000 miles, and its meridan altitude about 46deg. 29min. The palnet Mercury sets on September Ist at 7.37 p.m., and on September loth at 8.6 p.m., its apparent magnitudes on these dates will b..e 0.2 and 0.5 respectively. At the beginning of September it will set nearly due west but as the month progresses the point of setting will gradually move south. Venus rises on September Ist at 4.50. a.m., and on September lost at 1.48 a.m., 'Mars sets on these dates at 7.54. a.m. and 7.46 p.m. respectively Jupiter rises on September ]st at 1.43. a.m and on September loth at 0.54 a.m. Saturn sets on these dates at 11.20 p.m. and 10.26. p.m. respectively. The planets Venus and Neptune will be in conjunction about 11.30 p.m. on j September 27th; when they rise together on the following morning, Neptune will be found about 20 minutes of arc to the south of' its bright companion.

SUN-SPOTS,

Ratlier more than a century, has elapsed since Schwabe, a chemist living at Dessau, began the regular daily scrutiny of the sun which enabled him after 25 years of work, to announce that the spots which appear on the solar disc are periodic, one maximum following another at intervals of about 11 1-3 years. Subsequent investigation has entirely confirmed Schwabe’s discovery besides bringing to light, the fact that various terrestrial phe-> nomena are also associated with sunspots and subject to the same periodicity. A sun-spot is the surface manifestation of some deep-seated disturbance in the sun but we know neither the nature of this disturbance nor the cause of its regular recurrence in cycles: it is apparently a gigantic whirpool situated just below the photospheric level of the sun and is the seat of an intense magnetic field which is capable of producing magnetic effects on the earth’s surface. As it is this aspect of the sun-spot with which we are for the moment concerned we shall not now dwell upon other associated features.