The elements of astronomy; a textbook . steroid, withits perihelion just outside the orbit of Mars, and its aphelion close tothat of Jupiter, its period being a few days less than seven years. 399**. Photography of Comets. — It is now possible to photo-graph comets, and the photographs bring out numerous pecu-liarities and details which are not visible to the eye even withtelescopic aid. This is especially the case in the comets 100# is from Husseys photograph of Rordames comet of1893, for which we are indebted to the kindness of ProfessorHolden, director of the Lick Observatory. As
The elements of astronomy; a textbook . steroid, withits perihelion just outside the orbit of Mars, and its aphelion close tothat of Jupiter, its period being a few days less than seven years. 399**. Photography of Comets. — It is now possible to photo-graph comets, and the photographs bring out numerous pecu-liarities and details which are not visible to the eye even withtelescopic aid. This is especially the case in the comets 100# is from Husseys photograph of Rordames comet of1893, for which we are indebted to the kindness of ProfessorHolden, director of the Lick Observatory. As the camera waskept pointed at the head of the comet (which was movingpretty rapidly) the star-images during the hours exposure aredrawn out into parallel streaks, the little irregularities beingdue to faults of the driving-clock and vibrations of the tele-scope. The knots and streamers which characterize the com-ets tail were none of them visible in the telescope, and differfrom those shown upon plates taken on the days preceding and. COMET RORDAME, JULY 13, hy W. J. Hussey, at the Lick Observatory. § 399**] PHOTOGRAPHY OF COMETS. 289 following. Other plates, made the same evening a few hoursearlier and later, indicate that the knots were swiftly recedingfrom the comets head at a rate exceeding 150,000 miles anhour. Comets have several times lately been discovered by pho-tography in the same way as asteroids, — first by Barnardin 1892. METEORS AND SHOOTING STARS. 400. Meteorites. — Occasionally bodies fall upon the earthout of the sky. Until they reach the air they are usually in-visible, but as soon as they enter it they become conspicuous,and the pieces which fall are called Meteorites, Aerolites, Uranoliths, or simply meteoric stones. If the fall occurs at night, a ball of fire is seen, which moveswith an apparent velocity depending upon the distance of themeteor and the direction of its motion. The fire-ball is generallyfollowed by a luminous train,
Size: 1369px × 1825px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjec, booksubjectastronomy
