ROBERTS, Isaac.

Four photographs of stars and nebulae. 1887 – 1889.

Four actual photographs, each approximately 30 x 24 cm, mounted on card 43 x 30 cm with letterpress details at the head of each. Foxing on the mounts, corner of one mount slightly damaged. Provenance: Birr Castle Estate, Ireland, seat of the third earl of Rosse (1800–1867), who built the largest astronomical telescope in world, and the fourth earl (1840–1908), an equally distinguished astronomer.

The four photographs are: Photograph of stars in Cygnus. Taken at Maghull [Liverpool] on the 14th August, 1887, with 20-in. reflector, and exposure of 60 minutes. Photograph of the Dumb-Bell Nebula, M. 27 Vulpeculae. Exposure 3 hours, 3rd October, 1888. Enlarged 5 times. Maghull. Photograph of the great nebula in Andromeda. Taken at Maghull, on the 29th December, 1888, with 20-inch reflector, and exposure of 4 hours. Photograph of the nebulae. M. 81, 82 and a nebulous star in Ursa Major. Exposure 31⁄2 hours, 31st March 1889. Enlarged 5 times. Maghull. The headings also include co-ordinates for the subjects and references in the Monthly Notices of the Royal Astronomical Society. “In 1883, however, he began to experiment with stellar photography and eventually obtained a twenty-inch reflector, with a 100-inch focal length, from Howard Grubb of Dublin… In January 1886 Roberts announced to the Royal Astronomical Society that during the previous year he had taken 200 photographs of stars that might be measured for position and also long-exposure photographs of the Orion and Andromeda nebulae and of the Pleiades cluster. Later in 1886 he exhibited a 3-hour exposure of the Pleiades that revealed the astonishing and unsuspected nebulosity that surrounds these stars. In 1887 he attended the Conference of Astronomers in Paris; this conference planned an international photographic chart of the sky, and thereafter Roberts concentrated his own efforts on objects of special interest” (DSB). “In March, 1885, Sir Howard Grubb mounted for Dr. Isaac Roberts at Maghull, near Liverpool…a silver-on-glass reflector of twenty inches aperture, constructed expressly for use in celestial photography. A series of nebula pictures, obtained with this fine instrument, have proved highly instructive both as to the structure and extent of these wonderful objects” (Clerke, A Popular History of Astronomy, p. 409). Roberts’ astronomical photography earned him the Gold Medal of the Royal Astronomical Society in 1895, and a crater on the far side of the moon was jointly named in his honour.

£2,200.00

In stock

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