Gould's at Cordova and Stone's at the Cape.

After this we have a new departure. Gill at the Cape, having the comet
1882.ii. all to himself in those latitudes, wished his friends in
Europe to see it, and employed a local photographer to strap his
camera to the observatory equatoreal, driven by clockwork, and
adjusted on the comet by the eye. The result with half-an-hour's
exposure was good, so he tried three hours. The result was such a
display of sharp star images that he resolved on the Cape Photographic
Durchmusterung, which after fourteen years, with Kapteyn's aid in
reducing, was completed. Meanwhile the brothers Henry, of Paris, were
engaged in going over Chacornac's zodiacal stars, and were about to
catalogue the Milky Way portion, a serious labour, when they saw
Gill's Comet photograph and conceived the idea of doing the rest of
their work by photography. Gill had previously written to Admiral
Mouchez, of the Paris Observatory, and explained to him his project
for charting the heavens photographically, by combining the work of
many observatories. This led Admiral Mouchez to support the brothers
Henry in their scheme.[21] Gill, having got his own photographic work
underway, suggested an international astrographic chart, the materials
for different zones to be supplied by observatories of all nations,
each equipped with similar photographic telescopes. At a conference in
Paris, 1887, this was decided on, the stars on the charts going down
to the fourteenth magnitude, and the catalogues to the eleventh.

[Illustration: GREAT COMET, Nov. 14TH, 1882. (Exposure 2hrs. 20m.) By
kind permission of Sir David Gill. From this photograph originated all
stellar chart-photography.]

This monumental work is nearing completion. The labour involved was