A Search for Optical Signatures of Gamma
... follow-up multi-frequency study via GCN. ASTRAL consists of a set of 13 wide-field cameras (each with FOV = 70o) equipped with 4096x4096 CCDs. The detection method is based on the Digital Blink Comparator mode, with a template of a complete sample of ~2 million stars down to 12m, precisely measured ...
... follow-up multi-frequency study via GCN. ASTRAL consists of a set of 13 wide-field cameras (each with FOV = 70o) equipped with 4096x4096 CCDs. The detection method is based on the Digital Blink Comparator mode, with a template of a complete sample of ~2 million stars down to 12m, precisely measured ...
April 2013
... More lithium is found in meteorites and brown dwarfs than in burning stars; further evidence that Li is destroyed in stars. However, many low-mass, metal-poor, Li-rich red giants are known with 3Li7 abundances larger than the universe's primordial value, so the Li in these ...
... More lithium is found in meteorites and brown dwarfs than in burning stars; further evidence that Li is destroyed in stars. However, many low-mass, metal-poor, Li-rich red giants are known with 3Li7 abundances larger than the universe's primordial value, so the Li in these ...
L2-January 10/08
... naked-eye astronomy seasons, time and the calendar, precession origins of astronomy: prehistory (Stone Age) origins: Greek (beginnings of “science”?) ...
... naked-eye astronomy seasons, time and the calendar, precession origins of astronomy: prehistory (Stone Age) origins: Greek (beginnings of “science”?) ...
Article on Pluto (for 1st science news)
... the solar system--or that a new type of body even existed in the region--they assumed that designating the new discovery as the ninth planet was a scientifically accurate decision.. It has an eccentric orbit that crosses the path of Neptune and also takes it well above and below the main plane of th ...
... the solar system--or that a new type of body even existed in the region--they assumed that designating the new discovery as the ninth planet was a scientifically accurate decision.. It has an eccentric orbit that crosses the path of Neptune and also takes it well above and below the main plane of th ...
Chapter 1 Seeing the Light: The Art and Science of Astronomy
... happenings, and the investigation of the nature of the universe you live in. Professional astronomers carry out the business of astronomy by observing with telescopes that capture visible light from the stars or by tuning in to radio waves that come from space. They use backyard telescopes, huge obs ...
... happenings, and the investigation of the nature of the universe you live in. Professional astronomers carry out the business of astronomy by observing with telescopes that capture visible light from the stars or by tuning in to radio waves that come from space. They use backyard telescopes, huge obs ...
Flatfielding chapter for Calibration Volumes
... Second, the RoF incorporates lamp sources with well-calibrated irradiance that are monitored by NIST-calibrated photodiodes. The RoF thus provides an accurate absolute flux scale for the SNAP photometry. Third, the calibrated irradiance on the focal plane from the RoF provides a means to monitor var ...
... Second, the RoF incorporates lamp sources with well-calibrated irradiance that are monitored by NIST-calibrated photodiodes. The RoF thus provides an accurate absolute flux scale for the SNAP photometry. Third, the calibrated irradiance on the focal plane from the RoF provides a means to monitor var ...
Document
... Students will learn how to interpret observational characteristics of stars in terms of the underlying physical parameters You should gain an understanding of how stars of different mass evolve, and what end products are produced Students should learn what causes planetary nebulae and supernovae You ...
... Students will learn how to interpret observational characteristics of stars in terms of the underlying physical parameters You should gain an understanding of how stars of different mass evolve, and what end products are produced Students should learn what causes planetary nebulae and supernovae You ...
The First Star at Night
... horizon from here in Tasmania, one might expect that without Sirius in the sky, Canopus would always be the first star visible. However, it is rather more complicated than that. Even though we can always see Canopus at night - unless, of course, there are obstacles like hills or trees in the way Can ...
... horizon from here in Tasmania, one might expect that without Sirius in the sky, Canopus would always be the first star visible. However, it is rather more complicated than that. Even though we can always see Canopus at night - unless, of course, there are obstacles like hills or trees in the way Can ...
May 2013 - Joliet Junior College
... The stars of late spring and early summer are now in the evening sky and we’ve lost Orion and the winter constellations until next year - unless you want to go stargazing in the middle of the night. High In the mid-evening sky is the easiest group of stars to find the stars of the Big Dipper. The Bi ...
... The stars of late spring and early summer are now in the evening sky and we’ve lost Orion and the winter constellations until next year - unless you want to go stargazing in the middle of the night. High In the mid-evening sky is the easiest group of stars to find the stars of the Big Dipper. The Bi ...
http://hcs.harvard.edu/~jus/0302/bester.pdf
... on where in the nebular shell the knot lies. Those with the greatest angular velocity will be the ones with no velocity component towards or away from Earth; these are the knots on the outer edge of our image of the Crab. Table 2 shows the angular velocity and the estimated date of convergence of ea ...
... on where in the nebular shell the knot lies. Those with the greatest angular velocity will be the ones with no velocity component towards or away from Earth; these are the knots on the outer edge of our image of the Crab. Table 2 shows the angular velocity and the estimated date of convergence of ea ...
LT 9: I can describe how a protostar becomes a star.
... supergiants are the largest stars Giants: highly luminous, large stars Dwarfs: small, dim stars – White dwarfs: very faint, very dense, very ...
... supergiants are the largest stars Giants: highly luminous, large stars Dwarfs: small, dim stars – White dwarfs: very faint, very dense, very ...
Chapter 28 Stars and Their Characteristics
... the electromagnetic radiation. – The types of electromagnetic radiation can be arranged in a continuum called the Electromagnetic Spectrum (longest wavelengths at one end and shortest wavelengths at the other end) ...
... the electromagnetic radiation. – The types of electromagnetic radiation can be arranged in a continuum called the Electromagnetic Spectrum (longest wavelengths at one end and shortest wavelengths at the other end) ...
LIGHT VS. DISTANCE
... Inverse Square Law The brightness of an object varies inversely as the square of the distance. This is a geometric consequence of the fact that light moves outward in a spherical fashion. ...
... Inverse Square Law The brightness of an object varies inversely as the square of the distance. This is a geometric consequence of the fact that light moves outward in a spherical fashion. ...
Distant Stars Lesson Plan
... Introduce the Distant Stars segment as our first step beyond the reach of parallax. Point out that we’ll be adding two key rungs to our distance ladder called the H-R Diagram and Standard Candles. Show the video. Review what they saw: ...
... Introduce the Distant Stars segment as our first step beyond the reach of parallax. Point out that we’ll be adding two key rungs to our distance ladder called the H-R Diagram and Standard Candles. Show the video. Review what they saw: ...
PHYS_3380_091905_bw - in a secure place with other
... precise measurements of stellar and planetary positions - compiled best set of naked-eye observation ever made - to within 1 arcminute (thickness of a fingernail at arm’s length) - observed supernova of 1572 - proved it was farther away than the Sun - called it a nova (“new star”) - observed comet - ...
... precise measurements of stellar and planetary positions - compiled best set of naked-eye observation ever made - to within 1 arcminute (thickness of a fingernail at arm’s length) - observed supernova of 1572 - proved it was farther away than the Sun - called it a nova (“new star”) - observed comet - ...
The Milky Way
... • What causes the seasons? • How can astronomical cycles affect Earth’s climate? As you study the sky and its motions, you will be learning to think of Earth as a planet rotating on its axis. The next chapter will introduce you to some of the most dramatic cycles in the sky. ...
... • What causes the seasons? • How can astronomical cycles affect Earth’s climate? As you study the sky and its motions, you will be learning to think of Earth as a planet rotating on its axis. The next chapter will introduce you to some of the most dramatic cycles in the sky. ...
Journey to the Stars: Activities for Grades 9-12
... • The Universe is vast and estimated to be over ten billion years old. The current theory is that the Universe was created from an explosion called the Big Bang. Physical Setting 1.2b • Stars form when gravity causes clouds of molecules to contract until nuclear fusion of light elements into heavier ...
... • The Universe is vast and estimated to be over ten billion years old. The current theory is that the Universe was created from an explosion called the Big Bang. Physical Setting 1.2b • Stars form when gravity causes clouds of molecules to contract until nuclear fusion of light elements into heavier ...
Observational astronomy
Observational astronomy is a division of the astronomical science that is concerned with recording data, in contrast with theoretical astrophysics, which is mainly concerned with finding out the measurable implications of physical models. It is the practice of observing celestial objects by using telescopes and other astronomical apparatus.As a science, the study of astronomy is somewhat hindered in that direct experiments with the properties of the distant universe are not possible. However, this is partly compensated by the fact that astronomers have a vast number of visible examples of stellar phenomena that can be examined. This allows for observational data to be plotted on graphs, and general trends recorded. Nearby examples of specific phenomena, such as variable stars, can then be used to infer the behavior of more distant representatives. Those distant yardsticks can then be employed to measure other phenomena in that neighborhood, including the distance to a galaxy.Galileo Galilei turned a telescope to the heavens and recorded what he saw. Since that time, observational astronomy has made steady advances with each improvement in telescope technology.A traditional division of observational astronomy is given by the region of the electromagnetic spectrum observed: Optical astronomy is the part of astronomy that uses optical components (mirrors, lenses and solid-state detectors) to observe light from near infrared to near ultraviolet wavelengths. Visible-light astronomy (using wavelengths that can be detected with the eyes, about 400 - 700 nm) falls in the middle of this range. Infrared astronomy deals with the detection and analysis of infrared radiation (this typically refers to wavelengths longer than the detection limit of silicon solid-state detectors, about 1 μm wavelength). The most common tool is the reflecting telescope but with a detector sensitive to infrared wavelengths. Space telescopes are used at certain wavelengths where the atmosphere is opaque, or to eliminate noise (thermal radiation from the atmosphere). Radio astronomy detects radiation of millimetre to dekametre wavelength. The receivers are similar to those used in radio broadcast transmission but much more sensitive. See also Radio telescopes. High-energy astronomy includes X-ray astronomy, gamma-ray astronomy, and extreme UV astronomy, as well as studies of neutrinos and cosmic rays.Optical and radio astronomy can be performed with ground-based observatories, because the atmosphere is relatively transparent at the wavelengths being detected. Observatories are usually located at high altitudes so as to minimise the absorption and distortion caused by the Earth's atmosphere. Some wavelengths of infrared light are heavily absorbed by water vapor, so many infrared observatories are located in dry places at high altitude, or in space.The atmosphere is opaque at the wavelengths used by X-ray astronomy, gamma-ray astronomy, UV astronomy and (except for a few wavelength ""windows"") far infrared astronomy, so observations must be carried out mostly from balloons or space observatories. Powerful gamma rays can, however be detected by the large air showers they produce, and the study of cosmic rays is a rapidly expanding branch of astronomy.For much of the history of observational astronomy, almost all observation was performed in the visual spectrum with optical telescopes. While the Earth's atmosphere is relatively transparent in this portion of the electromagnetic spectrum, most telescope work is still dependent on seeing conditions and air transparency, and is generally restricted to the night time. The seeing conditions depend on the turbulence and thermal variations in the air. Locations that are frequently cloudy or suffer from atmospheric turbulence limit the resolution of observations. Likewise the presence of the full Moon can brighten up the sky with scattered light, hindering observation of faint objects.For observation purposes, the optimal location for an optical telescope is undoubtedly in outer space. There the telescope can make observations without being affected by the atmosphere. However, at present it remains costly to lift telescopes into orbit. Thus the next best locations are certain mountain peaks that have a high number of cloudless days and generally possess good atmospheric conditions (with good seeing conditions). The peaks of the islands of Mauna Kea, Hawaii and La Palma possess these properties, as to a lesser extent do inland sites such as Llano de Chajnantor, Paranal, Cerro Tololo and La Silla in Chile. These observatory locations have attracted an assemblage of powerful telescopes, totalling many billion US dollars of investment.The darkness of the night sky is an important factor in optical astronomy. With the size of cities and human populated areas ever expanding, the amount of artificial light at night has also increased. These artificial lights produce a diffuse background illumination that makes observation of faint astronomical features very difficult without special filters. In a few locations such as the state of Arizona and in the United Kingdom, this has led to campaigns for the reduction of light pollution. The use of hoods around street lights not only improves the amount of light directed toward the ground, but also helps reduce the light directed toward the sky.Atmospheric effects (astronomical seeing) can severely hinder the resolution of a telescope. Without some means of correcting for the blurring effect of the shifting atmosphere, telescopes larger than about 15–20 cm in aperture can not achieve their theoretical resolution at visible wavelengths. As a result, the primary benefit of using very large telescopes has been the improved light-gathering capability, allowing very faint magnitudes to be observed. However the resolution handicap has begun to be overcome by adaptive optics, speckle imaging and interferometric imaging, as well as the use of space telescopes.Astronomers have a number of observational tools that they can use to make measurements of the heavens. For objects that are relatively close to the Sun and Earth, direct and very precise position measurements can be made against a more distant (and thereby nearly stationary) background. Early observations of this nature were used to develop very precise orbital models of the various planets, and to determine their respective masses and gravitational perturbations. Such measurements led to the discovery of the planets Uranus, Neptune, and (indirectly) Pluto. They also resulted in an erroneous assumption of a fictional planet Vulcan within the orbit of Mercury (but the explanation of the precession of Mercury's orbit by Einstein is considered one of the triumphs of his general relativity theory).