TRANSIT OF VENUS.

Nelson Evening Mail, Volume IX, Issue 290, 8 December 1874, Page 2

TRANSIT OF VENUS.

As this interesting event, so long looked forward to, and for observing, which such extensive preparations have been made, takes place to-morrow, we again publish the times at which the various stages of contact will occur. They are as follows: — First external contact, lh. 25mins; First internal contact, lh. 54mins. Last internal contact, 6h. 28mins. Last) external contact, sh. 57mins. The following extract from a pamphlet published by Archdeacon Stock, of Wellington, will be interesting at the present time :— " The points of the transit that astronomers wish to notice especially are the exact times when Venus just enters fa ly upon the sun's disc, and just touches the disc on her way out. It might be thought that nothing could bereasier than to notice these times, as Venus is seen as a sharp black spot upon the sun. But when Venue has entered half her disc upon the sun, she begins to lose her roundness, and at last looks like a peg-top. It was this change of Venus that made the first transit observations uncertain. The peg is drawn out at the last into a fine line. When this line breaks, then is Venus fairly upon the sun. The better the telescope, the longer j will this line last This appearance must of necessity take place from the excessive brightness of the sun, causing it to appear larger than it is, and Venus smaller. It is due to this that we see the old moon, as it is said, in the new moon's arms. The same thing takes place in inverse order as Venus leaves the sun. Looking then at the sun on December 9th, 1874, Venus will just touch the sun's disc at sixteen minutes past one, and leave it at six o'clock— the transit lasting for nearly five hours. We shall see both the beginning and the end. The place where the pbnet will touch and leave the sun may be thus easily remembered. Suppose the sun to be figured as is the face of a clock, then Verus will ent»r upon the sun at twenty-two minutes past the hour, and leave it at thirty three minutes past. The transit will be readily seen through any telescope, if the eye piece be protected by a piece of dark-co'ored or smoked glass, and it is possible that Venus may just be visible to the naked eye when upon the sun." It appears that the transit of Venus which was observed by Captain Ciok'e expedition at Otaheite in 1 769 led to the calculation that the distance of the sun from the earth was 95,300,000 miles. It has since been considered — better astronomical instruments having come into use — that the distance is 91.750,000 miles. The next transits of Venus will be on Dtcember 6, 1982; June 7, 2004; June 5, 2012; December 10, 2117; December 8, 2!25; June 11, 2247; June 8, 2255; December 12,2360; December 10, 2868.