THE SOLAR ECLIPSE.

Evening Post, Volume XXX, Issue 59, 7 September 1885, Page 3

THE SOLAR ECLIPSE.

On Friday evening hut Dr. Heotor delivered an interesting leoture on the abovo subject to the Petone Institute, the following notes of whioh may be of service as guiding those who wish to observe tha eclipso that will be visible from Wellington, provided the weather is favourable, on Wednesday morniDg, between 7 and 8 o'olook :— The best point to observe from is any rising ground or hill-top that has a steep slope to the N.E. The Flagstaff hill, the top of the Botanical Gatdeni;. or the hill above Wadestown.are all moat favourable points for observation. Soon after snnrLse the eclipso commences, and the sun'a diso will be gradually obscured until, at 7.35 of New Zealand meantime, the total phase will oommenoe and hut for about 1 minute 38 second*. The sun at this time wiL have an altitude of 18 degrees and will bear about N.E. of the observer. The ohief interest of the eolipße will lie in the observation of the scarlet prominences and of the silvery light of tho corona or hale that surrounds the sun during the period of total darkness. The prominences may be expeoted to have great brillianoy, as for some weeks past the spots on the sun have shown that its Burface is in a state of violent activity, and ono of such unusual size aa to be almost visible to the naked eye, will havo reached such a position that it will ooinoide with the left hand edge of the sun at the time of the eclipse, and from this point unusually large flames should be looked for. For observing these flames it ia necessary, in order to intensify their light, to nse a fragment of rosetinted glass. On the other hand, to observe the light of the oorona to perfection, a very pole blue-tinted glass ia nsoessary, so aa to out off the red light and intensity the pole silvery light of the oorona. A telescope of high power ia quite unsuitable to the observer, but a wide field opera glass will be useful. Instructions have been received from the Committee of the Royal Society, whioh relate partly to the taking of a photographio, speotroscopio, and other observations that require speoial instruments, but the following extracts may be of use to moat observers:— Drawings of the oorona have only seldom proved to be of great utility. If snon drawings aro attempted on the present oooasion observers ought to pay attention to the general outline of tho oerona, rather than to points of detail. A plumb line ought to be suspended, if possible, between the observer and the sun, so as to fix the position of the oorona in the sky as aoonrately as possible. The vertical line ought to be indicated on the drawing. Observers will find it useful to draw- the blaok diso of the sun and the vertical line before the beginning of totality. . . . Observers unpractised in acourate drawing will obtain more usefnl results by paying attention to certain features of the oorona than by attempting what can only be a very rough and inacourate eketoh of the oorona. Definite answers aa to the following questions, for instance, would be of great value :- (a) To what distance from the sun, estimated in solar diameters, oan you trace the corona P (b) Does it extend further in aome directions than in others, and what are the directions of greatest and least extent P (c) Is there a line of approximate symmetry in the ootona, and what is the direotion of that line P The answers to the last two questions ought, if possible, to be given in angles from the vertioal line, or from some definite great oirple.