An introduction to photometry and photometric measurements Henry
... Vega magnitudes - II • Johnson (1966) described a broad-band photoelectric photometric system based on measurements of A0 stars like vega • Other work provides an absolute flux calibration linked to Vega. • Practical difficulties: (1) not everyone can (or should) observe Vega -- it’s much too bright ...
... Vega magnitudes - II • Johnson (1966) described a broad-band photoelectric photometric system based on measurements of A0 stars like vega • Other work provides an absolute flux calibration linked to Vega. • Practical difficulties: (1) not everyone can (or should) observe Vega -- it’s much too bright ...
The History of Infrared Spectroscopy
... infrared photography and his technique was so arcane that no one followed suit (Brand 1995). A better solution was required. A single infrared detector, if sufficiently small, can be placed at one end of a dispersed spectrum and slowly moved to the other end. The change in detected intensity with po ...
... infrared photography and his technique was so arcane that no one followed suit (Brand 1995). A better solution was required. A single infrared detector, if sufficiently small, can be placed at one end of a dispersed spectrum and slowly moved to the other end. The change in detected intensity with po ...
GRAVITY: Observing the Universe in Motion
... Integrated optics is widely used in telecommunications up to 1.6 μm, but does not cover the astronomically interesting K-band. GRAVITY has thus launched its own development programme between IPAG, LETI, and CIP to port the technology to longer wavelengths. Following a series of prototypes implementi ...
... Integrated optics is widely used in telecommunications up to 1.6 μm, but does not cover the astronomically interesting K-band. GRAVITY has thus launched its own development programme between IPAG, LETI, and CIP to port the technology to longer wavelengths. Following a series of prototypes implementi ...
Harappan Astronomy
... astronomy was based on the Sun, the Moon or the stars. There is extensive archaeological evidence that the Harappans traded with cultures in West Asia ((Kenoyer, 1998), Possehl, 2002)). The constellations as we know them today were formalised in Mesopotamia around 3000 BC ((see for example Wikipedia ...
... astronomy was based on the Sun, the Moon or the stars. There is extensive archaeological evidence that the Harappans traded with cultures in West Asia ((Kenoyer, 1998), Possehl, 2002)). The constellations as we know them today were formalised in Mesopotamia around 3000 BC ((see for example Wikipedia ...
Astrophotography
Astrophotography is a specialized type of photography for recording images of astronomical objects and large areas of the night sky. The first photograph of an astronomical object (the Moon) was taken in 1840, but it was not until the late 19th century that advances in technology allowed for detailed stellar photography. Besides being able to record the details of extended objects such as the Moon, Sun, and planets, astrophotography has the ability to image objects invisible to the human eye such as dim stars, nebulae, and galaxies. This is done by long time exposure since both film and digital cameras can accumulate and sum light photons over these long periods of time. Photography revolutionized the field of professional astronomical research, with long time exposures recording hundreds of thousands of new stars and nebulae that were invisible to the human eye, leading to specialized and ever larger optical telescopes that were essentially big cameras designed to collect light to be recorded on film. Direct astrophotography had an early role in sky surveys and star classification but over time it has given way to more sophisticated equipment and techniques designed for specific fields of scientific research, with film (and later astronomical CCD cameras) becoming just one of many forms of sensor.Astrophotography is a large sub-discipline in amateur astronomy where it is usually used to record aesthetically pleasing images, rather than for scientific research, with a whole range of equipment and techniques dedicated to the activity.