Astronomical observation, definition and study. A-Z index of Cognitio.

Astronomical observation or observational astronomy is the activity of observing heaven and celestial objects in the cosmic space, which can be carried out professionally or amateur, with or without a suitable instrumentation. 

Cosmic space, definition and study. A-Z index of Cognitio.

Cosmic space

The observation of the sky with a naked eye has a purely practical purpose and delight. It must necessarily be carried out in dark places away from light sources and in areas free from light scattering as much as possible. In this case, it is possible to identify the main constellations and the brightest objects in the sky such as the Andromeda galaxy.

Andromeda galaxy, definition and study. A-Z index of Cognitio.

Andromeda galaxy

 

Astronomical observation, definition and study. A-Z index of Cognitio.

Using a telescope allows you to observe weak objects at a resolution of hundreds of times greater than with a naked eye. This way you can observe planets and their surface, Moon surface details, nebulae, star clusters, galaxies, and so on.

Galaxy, definition and study. A-Z index of Cognitio.

Galaxy

Astronomical observation, definition and study. A-Z index of Cognitio.

The observation, in the history of observational astronomy, has for a long time been almost entirely done within the optical spectrum with optical telescopes. While the Earth’s atmosphere is relatively transparent in this portion of the electromagnetic spectrum, most of the work on the telescope is still dependent on the conditions of seeing and the transparency of the air and is generally limited to night hours. 

Atmosphere, definition and study. A-Z index of Cognitio.

Atmosphere

Astronomical observation, definition and study. A-Z index of Cognitio.

The visibility conditions depend on turbulence and atmospheric thermal variations. Sites that are frequently cloudy or are affected by atmospheric turbulence limit the resolution of the observations. Likewise, the presence of the full moon can illuminate the sky with diffused light, preventing the observation of objects that are less perceptible. In addition to the optical inspection of the universe, astronomers have been increasingly able to acquire information from other portions of the electromagnetic spectrum. The first non-optical measurements were made regarding the thermal properties of the Sun.

Sun, definition and study. A-Z index of Cognitio.

Sun

 

Astronomical observation, definition and study. A-Z index of Cognitio.

The instruments used during an eclipse could be used to measure radiation emitted from the crown. The key instrument of almost all modern observational astronomy is the telescope.

Moon eclipse, definition and study. A-Z index of Cognitio.

Moon eclipse

 This serves a dual purpose: collecting much light and magnifying the image so that very weak or small objects can be observed. For optical astronomy, the optical components used in a telescope have very demanding requirements that require great precision in their construction. Typical requirements for grinding and polishing a bent mirror, for example, require the surface to be within a fraction of a wavelength of light of a particular conical shape. Many modern “telescopes” are currently constituted by a telescopic apparatus that works together to provide a higher resolution through the opening summary. The photographic method allows further improvement in observation, allowing in some cases exceptional accuracy and quality. Particularly with photography, it is possible to get images hundreds of times sharper than those perceptible by the human eye placed in front of the eyebrow of a telescope. Astronomical photography, or astrophysics, is an astronomy field that requires professional equipment and experience. There are some observation tools:

 

The micrometer routing position.

The micrometer routing position.

The micrometer routing position.

Position micrometer is a tool that has been used to measure double stars. It consists of a pair of slim moving strips that can be moved together or separately. The telescope lenses are aligned on the pair and orientated using position wires that lie at right angles to the separation of the star. The movable wires are then adapted to compare the two-star positions. The separation of stars is then read on the instrument and their true separation is determined based on its magnification.

The spectroscope.

The spectroscope.

The spectroscope.

A living instrument of observational astronomy is the spectrograph. The absorption of specific elemental light wavelengths allows you to observe specific properties of distant bodies. This ability is derived from the discovery of helium in the Sun’s emission spectrum and has allowed astronomers to determine a great deal of information about distant stars, galaxies, and other celestial bodies. 

Stellar photometry.

Stellar photometry

Stellar photometry

Stellar photometry came into use in 1861 as one of the means to measure stellar colors. This technique measured the magnitude of a star in specific frequency fields, allowing a determination of the overall color, and hence its temperature. Since 1951, a standard international UBV (Ultraviolet-Blue-Visual) system was adopted.

 

The digital image

The digital image.

The digital image.

In recent years, in addition to photography, the use of CCDs and other digital devices such as cameras and cameras has been developed to capture and observe celestial objects on the telescope. The evolution, compared to photographic observation, is to improve the precision, but above all to the sensitivity of the sensor support.

Astronomical observation, definition and study. A-Z index of Cognitio.

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Astronomical observation, definition and study. A-Z index of Cognitio.

Astronomical observation