THE TRANSIT OF VENUS.

Ashburton Guardian, Volume IV, Issue 811, 6 December 1882, Page 2

THE TRANSIT OF VENUS.

To-morrow the much-talked of frajasit' of Venus across the sun’s disc will take place. In practical astronomy, remarks an exchange, the standard of measurement used is the sun’s distance from the ! earth ; and by the aid of this astronomical yard-measure, as' it has been teemed, the relative distances of the planets, and fixed stars are gauged, and various calculations are made. It will be readily under- ■ stood, therefore, that astronomers have’ ’ been, and still are, specially anxious that their standard of measurement should be unmistakably known, and that every opportunity for testing its accuracy Should be taken advantage of. For this purpose (determining the sun’s average distance)* the passing of Venus between us' and the?*-, sun affords us the most reliable means of obtaining the necessary data. The first recorded observation oF ,( the transit of Venus took place December 4, 1639, the next on June 5, 1671, the next on June 3rd, 1769, and after to-morrow there will be no transit until June 7, 2004, another taking place on June 5, 2012. Therefore this is the last opportunity that the present dwellers on the earth will have of witnessing the transit of fenus. We are told that “ The whole duration of the transit will not be visible in this colony. The external contact at ingress takes place at Ih. 46min, ISsecs. a.m., New Zealand mean time, and consequently when the sun rises the transit of Venus across the sun's disc will be in progress. What observers stationed fh Australia and New Zealand have to direct their attention to is the internal contact at egress, that is to say when the outer edges of both the sun and the planet pear to coincide. This takes place at. ’ about 7h. 21miu. 46sec., and the external contact at 7b. 42min. dsec. on the morning of Thursday. ” We have keard that a card perforated with a fine needle makes an excellent medium through which to watch the sun, and is preferable for that purpose, to smoked glass.