Richard A. Proctor
Richard Anthony Proctor was an English astronomer. He is best remembered for having produced one of the earliest maps of Mars in 1867 from 27 drawings by the English observer William Rutter Dawes, his map was superseded by those of Giovanni Schiaparelli and Eugène Antoniadi and his nomenclature was dropped. He used old drawings of Mars dating back to 1666 to try to determine the sidereal day of Mars, his final estimate, in 1873, was 24h 37m 22.713s close to the modern value of 24h 37m 22.663s. Frederik Kaiser's value of 24h 37m 22.622s is closer, by 0.012 seconds in 88,642.688 seconds, a small difference in the error of both computations. The crater Proctor on Mars is named after him, he was a delicate child, his father dying in 1850, his mother attended herself to his education. On his health improving he was sent to King's College London, subsequently earned a scholarship at St John's College, Cambridge, he graduated in 1860 as 23rd wrangler. His marriage while still an undergraduate accounted for his low place in the tripos.
He read for the bar, but turned to astronomy and authorship instead, in 1865 published an article on the Colors of Double Stars in the Cornhill Magazine. His first book Saturn and its System was published at his own expense; this work contains an elaborate account of the phenomena presented by the planet. He intended to follow it up with similar treatises on Mars, Sun, Moon and meteors, nebulae, had in fact commenced a monograph on Mars, when the failure of a New Zealand bank deprived him of an independence which would have enabled him to carry out his scheme without anxiety as to its commercial success or failure. Being thus obliged to depend upon his writings for the support of his family, having learned by the fate of his Saturn and its System that the general public are not attracted by works requiring arduous study, he cultivated a more popular style, he wrote for a number of periodicals. His earlier efforts were, not always successful, his Handbook of the Stars was refused by Messrs Longmans and Messrs Macmillan, but being printed, it sold well.
For his Half-Hours with the Telescope, which reached a 20th edition, he received £25 from Messrs Hardwick. Although teaching was uncongenial to him he took pupils in mathematics, held for a time the position of mathematical coach for Woolwich and Sandhurst, his literary standing meantime improved, he became a regular contributor to The Intellectual Observer, Chamber's Journal and the Popular Science Review. In 1870 appeared his Other Worlds Than Ours, in which he discussed the question of the plurality of worlds in the light of new facts; this was followed by a long series of popular treatises in rapid succession, amongst the more important of which are Light Science for Leisure Hours and The Sun. In 1881 he founded Knowledge, a popular weekly magazine of science, which had a considerable circulation. In it he wrote including chess and whist, he was the author of the articles on astronomy in the American Cyclopaedia and the ninth edition of the Encyclopædia Britannica, was well known as a popular lecturer on astronomy in England and Australia.
Elected a fellow of the Royal Astronomical Society in 1866, he became honorary secretary in 1872, contributed eighty-three separate papers to its Monthly Notices. Of these the more noteworthy dealt with the distribution of stars, star clusters and nebulae, the construction of the sidereal universe, he was an expert in all that related to map-drawing, published two star-atlases. A chart on an isographic projection, exhibiting all the stars contained in the Bonner Durchmusterung, was designed to show the laws according to which the stars down to the 9–10th magnitude are distributed over the northern heavens, his Theoretical Considerations respecting the Corona deserve mention, as well as his discussions of the rotation of Mars, by which be deduced its period with a probable error of 0.005. He vigorously criticised the official arrangements for observing the transits of Venus of 1874 and 1882, his largest and most ambitious work and New Astronomy, left unfinished at his death, was completed by Arthur Cowper Ranyard and published in 1892 with a second edition in 1895.
He settled in America some time after his second marriage in 1881, died of yellow fever at New York City on 12 September 1888. A monument was erected in his memory. Mary Proctor, his daughter by his first marriage, became an astronomer and a
Infrared radiation, sometimes called infrared light, is electromagnetic radiation with longer wavelengths than those of visible light, is therefore invisible to the human eye, although IR at wavelengths up to 1050 nanometers s from specially pulsed lasers can be seen by humans under certain conditions. IR wavelengths extend from the nominal red edge of the visible spectrum at 700 nanometers, to 1 millimeter. Most of the thermal radiation emitted by objects near room temperature is infrared; as with all EMR, IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon. Infrared radiation was discovered in 1800 by astronomer Sir William Herschel, who discovered a type of invisible radiation in the spectrum lower in energy than red light, by means of its effect on a thermometer. More than half of the total energy from the Sun was found to arrive on Earth in the form of infrared; the balance between absorbed and emitted infrared radiation has a critical effect on Earth's climate.
Infrared radiation is emitted or absorbed by molecules when they change their rotational-vibrational movements. It excites vibrational modes in a molecule through a change in the dipole moment, making it a useful frequency range for study of these energy states for molecules of the proper symmetry. Infrared spectroscopy examines transmission of photons in the infrared range. Infrared radiation is used in industrial, military, law enforcement, medical applications. Night-vision devices using active near-infrared illumination allow people or animals to be observed without the observer being detected. Infrared astronomy uses sensor-equipped telescopes to penetrate dusty regions of space such as molecular clouds, detect objects such as planets, to view red-shifted objects from the early days of the universe. Infrared thermal-imaging cameras are used to detect heat loss in insulated systems, to observe changing blood flow in the skin, to detect overheating of electrical apparatus. Extensive uses for military and civilian applications include target acquisition, night vision and tracking.
Humans at normal body temperature radiate chiefly at wavelengths around 10 μm. Non-military uses include thermal efficiency analysis, environmental monitoring, industrial facility inspections, detection of grow-ops, remote temperature sensing, short-range wireless communication and weather forecasting. Infrared radiation extends from the nominal red edge of the visible spectrum at 700 nanometers to 1 millimeter; this range of wavelengths corresponds to a frequency range of 430 THz down to 300 GHz. Below infrared is the microwave portion of the electromagnetic spectrum. Sunlight, at an effective temperature of 5,780 kelvins, is composed of near-thermal-spectrum radiation, more than half infrared. At zenith, sunlight provides an irradiance of just over 1 kilowatt per square meter at sea level. Of this energy, 527 watts is infrared radiation, 445 watts is visible light, 32 watts is ultraviolet radiation. Nearly all the infrared radiation in sunlight is shorter than 4 micrometers. On the surface of Earth, at far lower temperatures than the surface of the Sun, some thermal radiation consists of infrared in the mid-infrared region, much longer than in sunlight.
However, black body or thermal radiation is continuous: it gives off radiation at all wavelengths. Of these natural thermal radiation processes, only lightning and natural fires are hot enough to produce much visible energy, fires produce far more infrared than visible-light energy. In general, objects emit infrared radiation across a spectrum of wavelengths, but sometimes only a limited region of the spectrum is of interest because sensors collect radiation only within a specific bandwidth. Thermal infrared radiation has a maximum emission wavelength, inversely proportional to the absolute temperature of object, in accordance with Wien's displacement law. Therefore, the infrared band is subdivided into smaller sections. A used sub-division scheme is: NIR and SWIR is sometimes called "reflected infrared", whereas MWIR and LWIR is sometimes referred to as "thermal infrared". Due to the nature of the blackbody radiation curves, typical "hot" objects, such as exhaust pipes appear brighter in the MW compared to the same object viewed in the LW.
The International Commission on Illumination recommended the division of infrared radiation into the following three bands: ISO 20473 specifies the following scheme: Astronomers divide the infrared spectrum as follows: These divisions are not precise and can vary depending on the publication. The three regions are used for observation of different temperature ranges, hence different environments in space; the most common photometric system used in astronomy allocates capital letters to different spectral regions according to filters used. These letters are understood in reference to atmospheric windows and appear, for instance, in the titles of many papers. A third scheme divides up the band based on the response of various detectors: Near-infrared: from 0.7 to 1.0 µm. Short-wave infrared: 1.0 to 3 µm. InGaAs covers to about 1.8 µm. Mid-wave infrared: 3 to 5 µm (defined by the atmospheric window and covered by indium antimonide and mercury cadmium telluride and by lead
The Carina–Sagittarius Arm is thought to be a minor spiral arm of the Milky Way galaxy. Each spiral arm is a diffuse curving streamer of stars that radiates from the galactic center; these gigantic structures are composed of billions of stars and thousands of gas clouds. The Carina–Sagittarius Arm is one of the most pronounced arms in our galaxy as a large number of HII regions, young stars and giant molecular clouds are concentrated in it; the Milky Way is a barred spiral galaxy, consisting of a central crossbar and bulge from which two major and several minor spiral arms radiate outwards. The Carina–Sagittarius Arm lies between two major spiral arms—the Scutum–Centaurus Arm the near part of, visible looking inward i.e. toward the galactic centre with the rest beyond the galactic centre and the Perseus Arm, similar in size and shape but locally positioned outward. It is named for its proximity to the Sagittarius and Carina constellations as seen in the night sky from Earth, in the direction of the galactic center.
The arm dissipates near its middle, shortly after reaching its maximal angle, viewed from our solar system, from the galactic centre of about 80°. Extending from the galaxy's central bar is the Sagittarius Arm. Beyond the dissipated zone it is the Carina Arm. In 2008, infrared observations with the Spitzer Space Telescope showed that the Carina–Sagittarius Arm has a relative paucity of young stars, in contrast with the Scutum-Centaurus Arm and Perseus Arm; this suggests. These two appear to be concentrations of gas, sparsely sprinkled with pockets of newly formed stars. A number of Messier objects and other objects visible through an amateur's telescope or binoculars are found in the Sagittarius Arm: M11, the Wild Duck Cluster in Scutum Open Cluster M26 in Scutum M16, the Eagle Nebula in Serpens M17, the Omega Nebula in Sagittarius Open Cluster M18 in Sagittarius Globular Cluster M55 in Sagittarius M24, the Sagittarius Star Cloud Open Cluster M21 in Sagittarius M8, the Lagoon Nebula in Sagittarius NGC 3372, the Carina Nebula in Carina http://members.fcac.org/~sol/chview/chv5.htm Messier Objects in the Milky Way
Maffei 1 is a massive elliptical galaxy in the constellation Cassiopeia. Once believed to be a member of the Local Group of galaxies, it is now known to belong to its own group, the IC 342/Maffei Group, it was named after Paolo Maffei, who discovered it and the neighboring Maffei 2 in 1967 via their infrared emissions. Maffei 1 is a flattened core type elliptical galaxy, it has a boxy shape and is made of old metal-rich stars. It has a tiny blue nucleus. Like all large ellipticals it contains a significant population of globular clusters. Maffei 1 is situated at an estimated distance of 3–4 Mpc from the Milky Way, it may be the closest giant elliptical galaxy. Maffei 1 lies in the Zone of Avoidance and is obscured by the Milky Way's stars and dust. If it were not obscured, it would be one of the largest and best-known galaxies in the sky, it can be observed visually, using a 30–35 cm or bigger telescope under a dark sky. The Italian astronomer Paolo Maffei was one of the pioneers of infrared astronomy.
In the 1950s and 60s, in order to obtain high quality images of celestial objects in the near infrared part of the spectrum, he used chemically hyper-sensitized standard Eastman emulsions I-N. To achieve the hyper-sensitization he immersed them in 5% ammonia solution for 3–5 minutes; this procedure increased their sensitivity by an order of magnitude. Between 1957 and 1967 Maffei observed many different objects using this technique, including globular clusters and planetary nebulae; some of those objects were not visible at all on blue light sensitive plates. The galaxy Maffei 1 was discovered on a hyper-sensitized I-N photographic plate exposed on 29 September 1967 with the Schmidt telescope at Asiago Observatory. Maffei found Maffei 1, together with its companion spiral galaxy Maffei 2, while searching for diffuse nebulae and T Tauri stars; the object had an apparent size up to 50″ in the near infrared but was not visible on the corresponding blue light sensitive plate. Its spectrum lacked any absorption lines.
It was shown to be radio-quiet as well. In 1970 Hyron Spinrad suggested that Maffei 1 is a nearby obscured giant elliptical galaxy. Maffei 1 would be among the ten brightest galaxies in the northern sky if not situated behind the Milky Way. Maffei 1 is located only 0.55° from the galactic plane in the middle of the zone of avoidance and suffers from about 4.7 magnitudes of extinction in visible light. In addition to extinction, observation of Maffei 1 is further hindered by the fact that it is covered by myriads of faint Milky Way stars, which can be confused with its own; as a result, determining its distance has been difficult. In 1971, soon after its discovery, Hyron Spinrad estimated the distance to Maffei 1 at about 1 Mpc, which would place it within the Local Group of galaxies. In 1983 this estimate was revised up to 2.1+1.3−0.8 Mpc by Ronald Buta and Marshall McCall using the general relation between the luminosity and velocity dispersion for elliptical galaxies. That distance puts Maffei 1 well outside the Local Group, but close enough to have influenced it in the past.
In 1993 Gerard Luppino and John Tonry used surface brightness fluctuations to derive a new distance estimate to Maffei 1 of 4.15 ± 0.5 Mpc. In 2001, Tim Davidge and Sidney van den Bergh used adaptive optics to observe the brightest asymptotic giant branch stars in Maffei 1 and concluded that it is located at the distance 4.4+0.6−0.5 Mpc from the Sun. The latest determination of the distance to Maffei 1, based on the re-calibrated luminosity/velocity dispersion relation for the elliptical galaxies and the updated extinction, is 2.85 ± 0.36 Mpc. The larger distances reported in the past 20 years would imply that Maffei 1 has never been close enough to the Local Group to influence its dynamics. Maffei 1 moves away from the Sun at the speed of about 66 km/s, its velocity relative to the Local Group's center of mass is, however, 297 km/s away. That means. Maffei 1 is a massive elliptical galaxy classified as type E3 in the Hubble classification scheme; this means that it is flattened, its semi-minor axis being 70% of its semi-major axis.
Maffei 1 has a boxy shape, while its central region is deficient in light emission as compared to the r1/4 law, meaning that Maffei 1 is a core type elliptical. Both the boxy shape and the presence of an underluminous core are typical of intermediate to massive ellipticals; the apparent dimensions of Maffei 1 depend on the wavelength of light because of the heavy obscuration by the Milky Way. In blue light it is 1–2′ across while in the near infrared its major axis reaches 23′—more than 3/4 of the Moon's diameter. At a distance of 3 Mpc this corresponds to 23 kpc; the total visible absolute magnitude of Maffei 1, MV=−20.8, is comparable to that of the Milky Way. Maffei 1 possesses a tiny blue nucleus at its center 1.2 pc across. It contains about 29 solar masses of ionized hydrogen; this implies. There are no signs of an active galactic nucleus in the center of Maffei 1; the X-ray emission from the center is extended and comes from a number of stellar sources. Maffei 1 is made of old metal-rich stars more than 10 billion years in age.
As a large elliptical galaxy, Maffei 1 is expected to host a significant population of globular clusters. However, due to heavy intervening absorption, ground-based observations for a long time failed to identify any of them. Observations by the Hubble Space Telescope in 2
The Galactic Center, or Galactic Centre, is the rotational center of the Milky Way. It is 8,122 ± 31 parsecs away from Earth in the direction of the constellations Sagittarius and Scorpius where the Milky Way appears brightest, it coincides with the compact radio source Sagittarius A*. There are around 10 million stars within one parsec of the Galactic Center, dominated by red giants, with a significant population of massive supergiants and Wolf-Rayet stars from a star formation event around one million years ago, one supermassive black hole of 4.100 ± 0.034 million solar masses at the Galactic Center, which powers the Sagittarius A* radio source. Because of interstellar dust along the line of sight, the Galactic Center cannot be studied at visible, ultraviolet, or soft X-ray wavelengths; the available information about the Galactic Center comes from observations at gamma ray, hard X-ray, infrared and radio wavelengths. Immanuel Kant stated in General Natural History and Theory of the Heavens that a large star was at the center of the Milky Way Galaxy, that Sirius might be the star.
Harlow Shapley stated in 1918 that the halo of globular clusters surrounding the Milky Way seemed to be centered on the star swarms in the constellation of Sagittarius, but the dark molecular clouds in the area blocked the view for optical astronomy. In the early 1940s Walter Baade at Mount Wilson Observatory took advantage of wartime blackout conditions in nearby Los Angeles to conduct a search for the center with the 100-inch Hooker Telescope, he found that near the star Alnasl there is a one-degree-wide void in the interstellar dust lanes, which provides a clear view of the swarms of stars around the nucleus of our Milky Way Galaxy. This gap has been known as Baade's Window since. At Dover Heights in Sydney, Australia, a team of radio astronomers from the Division of Radiophysics at the CSIRO, led by Joseph Lade Pawsey, used'sea interferometry' to discover some of the first interstellar and intergalactic radio sources, including Taurus A, Virgo A and Centaurus A. By 1954 they had built an 80-foot fixed dish antenna and used it to make a detailed study of an extended powerful belt of radio emission, detected in Sagittarius.
They named an intense point-source near the center of this belt Sagittarius A, realised that it was located at the center of our Galaxy, despite being some 32 degrees south-west of the conjectured galactic center of the time. In 1958 the International Astronomical Union decided to adopt the position of Sagittarius A as the true zero co-ordinate point for the system of galactic latitude and longitude. In the equatorial coordinate system the location is: RA 17h 45m 40.04s, Dec −29° 00′ 28.1″. The exact distance between the Solar System and the Galactic Center is not certain, although estimates since 2000 have remained within the range 24–28.4 kilolight-years. The latest estimates from geometric-based methods and standard candles yield the following distances to the Galactic Center: 7.4±0.2 ± 0.2 or 7.4±0.3 kpc 7.62±0.32 kpc 7.7±0.7 kpc 7.94 or 8.0±0.5 kpc 7.98±0.15 ± 0.20 or 8.0±0.25 kpc 8.33±0.35 kpc 8.7±0.5 kpc An accurate determination of the distance to the Galactic Center as established from variable stars or standard candles is hindered by countless effects, which include: an ambiguous reddening law.
The nature of the Milky Way's bar, which extends across the Galactic Center, is actively debated, with estimates for its half-length and orientation spanning between 1–5 kpc and 10–50°. Certain authors advocate that the Milky Way features two distinct bars, one nestled within the other; the bar is delineated by red-clump stars. The bar may be surrounded by a ring called the 5-kpc ring that contains a large fraction of the molecular hydrogen present in the Milky Way, most of the Milky Way's star formation activity. Viewed from the Andromeda Galaxy, it would be the brightest feature of the Milky Way; the complex astronomical radio source Sagittarius A appears to be located exactly at the Galactic Center, contains an intense compact radio source, Sagittarius A*, which coincides with a supermassive black hole at the center of the Milky Way. Accretion of gas onto the black hole involving an accretion disk around it, would release energy to power the radio source, itself much larger than the black hole.
The latter is too small to see with present instruments. A study in 2008 which linked radio telescopes in Hawaii and California measured the diameter of Sagittarius A* to be 44 million kilometers. For comparison, the radius of Earth's orbit around the Sun is about 150 million kilometers, whereas the distance of Mercury from the Sun at closest approach is 46 million kilometers. Thus, the diameter of the radio source is less than the distance from Mercury to the Sun. Scientists at the Max Planck Institute for Extraterrestrial Physics in Germany using Chilean telescopes have confirmed the existence of a superm