astrophotography

Use of photography in astronomical research. The first successful photograph of a celestial object was the daguerreotype plate of the Moon taken by English Scientist John W Draper in March 1840. The first photograph of a star, Vega, was taken by US astronomer William Bond in 1850. Modern-day astrophotography uses techniques such as charge-coupled devices (CCDs), which are often carried aboard a spacecraft.

Before the development of photography, observations were gathered in the form of sketches made at the telescope. Several successful daguerrotypes were obtained prior to the introduction of wet-plate collodion about 1850. The availability of this more convenient method allowed photography to be used on a more systematic basis, including the monitoring of sunspot activity. Dry plates were introduced in the 1870s, and in 1880 Henry Draper obtained a photograph of the Orion nebula. The first successful image of a comet was obtained 1882 by the Scottish astronomer David Gill, his plate displaying excellent star images. Following this, Gill and Duthe Astronomer J C Kapteyn compiled the first photographic atlas of the southern sky, cataloguing almost half a million stars.

Modern-day electronic innovations, notably charge-coupled devices (CCDs), provide a more efficient light-gathering capability than photographic film as well as enabling information to be transferred to a computer for analysis. However, CCDs are expensive and very small in size compared to photographic plates. Photographic plates are better suited to wide-field images, whereas CCDs are used for individual objects, which may be very faint, within a narrow field of sky.