PHOTOGRAPHING AN OBJECT WHICH HAS NEVER BEEN SEEN BY MAN.

New Zealand Times, Volume XLVI, Issue 7775, 6 May 1886, Page 4

PHOTOGRAPHING AN OBJECT WHICH HAS NEVER BEEN SEEN BY MAN.

Some weeks ago we alluded in our ‘Notes * to the possibility of some day securing photographs of the 1 dark suns’ which are believed to exist in space—worn out, usedup, decrepit bodies -no longer capable of emitting light, but yet many of them perhaps still at a temperature but little below that at which they would be visible. Half in jest and half in earnest, we ventured the suggestion that by using plates specially prepared so as to be sensitive to those red and ultra-red rays which are alone emitted by bodies at or just below a red heat, it might be barely possible to secure a record of the position of these as yet unseen wonders in space. In such a photography would be the means of furnishing a record of that which the human eye hsd never beheld, and could never hope to behold. Thefiockingout into sudden brilliancy of new stars, and the formation of new nebulte, has been thought to be due to the collision ‘ of such dark suns ’either with one another, or with some solar system like our own —still in comparative youth —as they journeyed on in space. In such a case photography might enable ua to foresee, though not to avert, the catastrophe. As far as regards the securing of a record of the presence and position of a heavenly body which has never been seen by man—and which, so far, has not been seen even now that we know where to direct our telescopes—ourwonderfnlaciencehas already fulfilled our prophecy. We have alluded more than once to the magnificent work which is being done in connection with the Paris Observatory by the brothers MM, Paul and Prosper Henry, whose optical factory has turned out some of the finest telescope objectives ever made. Not long since the Brothers Henry completed an objective of 13J inches aperture, designed expressly for celestial photography, and the mounting and fitting of this instrument, together with the driving machinery by which the instrument is kept constantly pointing to any given part of sky, are of the most refined and delicate construction. When a sensitive dry plate is placed in the dark-slide, which is fitted to the lower end of the telescope-tube (occupying the position of the eye), the images of the stars, &0., are received on the film, and it is found that an exposure of from one to two hours duration is sufficient to secure a record of stars down to the 15th or 16th magnitudes—stars below the sixth magnitude being invisible to the naked eye, llut the most remarkable discovery yet made is that there exist in the heavens bodies capable of impressing their images on a sensitive plate, but which have never, as yet, been seen through any telescope, and which cannot even be seen through the same telescope by which they are photographed. The star cluster called the Pleiades is one of the most famous in the heavens. To the naked eye it shows some six or seven stars, but the tela' scope reveals many more. These stars have been mapped, and the cluster has been carefully studied with the greatest care and with th» most powerful instruments, by many famous astronomers. We can imagine then the surprise of the Parisian astronomers when, on November 6 last, they saw, on developing a negative which had been exposed to the light of the Pleiades, not only all the stars with whose presence they were already familiar, hut a new nebula. To prevent the possibility of any mistake, the same region was again photographed on December 8 and December 9, and identically the same results were obtained. The new body is described as being of a diameter of three minutes, very intense, and presenting a well marked shape, a shape which is characteristic of many nebuhe. Its exact position in the sky is right ascension, 8 hrs, 38 min. 57 sec. ; declination, 24 deg. 1 min. north. It will now be a matter of the highest interest to ascertain whether this nebula is visible through more powerful telescopes : such as the famous refractor at Washington, the diameter of whose object glass is 26 inches. The nature of the light emitted, too, which is able so powerfully to impress its image on the dry plate while it cannot affect the nerves of the eye, must be a matter of great interest: though we fear that from the feebleness of its light it may be impossible to examine it through the spectroscope. Still, that instrument used in connection with a camera may give indication of its nature. The position which photography is assuming in connection with astronomy is, indeed, of the highest importance ; and it must be a matter of gratification to every photographer : that his favorite art is able to render such 1 valuable aid to this, the oldest of the sciences.—Photographic News.