History

Photography in astronomical observation

Photography in astronomical observation

Astronomical photography or astrophotography It is an exciting technique that allows you to capture the images of celestial bodies. The use of photography in astronomy offers a number of advantages over observation with the naked eye.

Astrophotography allows to capture those radiations of intensity too weak to be perceived by the human eye. For this it is necessary to make an exhibition for a considerable time. Likewise, and thanks to the use of interferential filters, photographs can be obtained under the light of some spectral lines, obtaining data on the composition of its original light source.

Astrophotography material

Contrary to what it may seem, to take astronomical photographs you do not need to spend too much. Compact digital cameras of quality and accessible cost are perfectly valid. It is necessary that they have a good optical quality, in addition to the configuration options in exposure times, sensitivity, aperture and focus.

In order to photograph distant objects, it is preferable to use a SLR camera. This is due to its wide range of exposure options. There are a type of SLR cameras, the DSLR (Digital Single Lens Reflex), which can be adapted to telescopes, obtaining much more detailed and higher quality images.

Astrophotography techniques

At the amateur level, there are several types of astronomical photography techniques. This is the case of the Star Trail system, the most common, which consists of capturing images of the stars that leave a trail in the sky. It can be done with all types of cameras, usually mounted on a tripod.

Another technique is tracking photography, which is done with equipment such as computerized telescopes or motorized frames.

For its part, the technique of lunar and planetary photographs can be practiced with almost all cameras, either with a direct objective, through a telescope with DSLR system or with a webcam. Finally, the Stacking technique allows you to capture images on video. The recommended resolution is the VGA, and requires considerable filming time. Subsequently it is edited with the help of special software. The best frames of the video are accumulated as images, and a single shot is obtained.

Astrophotography Milestones

It was the year 1840 when Anglo-American chemist John William Draper got an image of the moon after a 20-minute exposure. For this he used an eight centimeter diameter lens. It was the first astronomical photograph taken in North America. Two years later, the French physicist Alexander Becquerel managed to photograph the solar spectrum for the first time.

Already in 1851, the director of the Harvard Observatory, John Whipple, managed to obtain a daguerreotype of the Moon. With this image he won a gold medal in an exhibition and was widely praised by the French Academy of Sciences. In 1852 the British astronomer Warren de la Rue, using the collodion method and with a 33 cm reflector, obtained good images of the Moon in less than half a minute of exposure.

But, without a doubt, the year 1882 was one of the best for astrophotography. That year the Scottish astronomer David Gill got a fantastic image of a large comet at the Cape Town observatory in South Africa. He used a telescope to follow the comet and a camera mounted on one of the counterweights with the lens open. This photograph completely revolutionized the world of astronomy.

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