Astronomical Term *Mezzocielo*

Astronomical Term *Mezzocielo*

What is the name of the point of intersection of the great circle passing through the celestial north pole P and the Zenith Z, with the celestial equator? (Point T in the figure)

In Italian this point is called "Mezzocielo" (English machine translation), which translates into mid-sky, since it is located halfway between the Zenith and the horizon for an observer in Italy ($phi approx 40^{circ}$).

I've checked several sources. Where this term appears in dictionaries, it is translated with a definition, and not a gloss (usually if a direct translation exists in English only a gloss is given) For example intersection of the meridian of a given place with the celestial equator.

I conclude that English speaking astronomers have not had the benefit of single word translation of mezzocielo.

Astronomy Terms

Astronomy Terms can help get you up-to-speed some terms of stargazing and the science of astronomy. Our Astronomy Glossary has the essentials of carefully sourced terms and definitions to answer many questions like:

  • Find out the difference between a reflector and a refractor telescope.
  • Find out the difference between a meteor and meteorite.
  • Find out the different phases of the Moon.

Angular Size and Distance
The apparent size of an object in the sky, or the distance between two objects, measured as an angle. Your index finger held at arm’s length spans about 1°, your fist about 10°.

The diameter of a telescope’s main lens or mirror — and the scope’s most important attribute. As a rule of thumb, a telescope’s maximum useful magnification is 50 times its aperture in inches (or twice its aperture in millimeters).

Any prominent star pattern that isn’t a whole constellation, such as the Northern Cross or the Big Dipper.

Asteroid (Minor Planet)
A solid body orbiting the Sun that consists of metal and rock. Most are only a few miles in diameter and are found between the orbits of Mars and Jupiter, too small and far away to be seen easily in a small telescope. A few venture closer to the Sun and cross Earth’s orbit.

Astronomical Unit
The average distance from Earth to the Sun, slightly less than 93 million miles.

Averted Vision
Viewing an object by looking slightly to its side. This technique can help you detect faint objects that are invisible when you stare directly at them.

Barlow Lens
A lens that’s placed into the focusing tube to effectively double or triple a telescope’s focal length and, in turn, the magnification of any eyepiece used with it.

Black Hole
A concentration of mass so dense that nothing — not even light — can escape its gravitational pull once swallowed up. Many galaxies (including ours) have supermassive black holes at their centers.

Blue Moon
Traditionally, something that happens rarely or never. More recently, this has come to mean the second full Moon in a single calendar month.

Celestial Coordinates
A grid system for locating things in the sky. It’s anchored to the celestial poles (directly above Earth’s north and south poles) and the celestial equator (directly above Earth’s equator). Declination and right ascension are the celestial equivalents of latitude and longitude.

Denotes an object near a celestial pole that never dips below the horizon as Earth rotates and thus does not rise or set.

Aligning the optical elements of a telescope so that they all point in the proper direction. Most reflectors and compound telescopes require occasional collimation in order to produce the best possible images.

A “dirty snowball” of ice and rocky debris, typically a few miles across, that orbits the Sun in a long ellipse. When close to the Sun, the warmth evaporates the ice in the nucleus to form a coma (cloud of gas) and a tail. Named for their discoverers, comets sometimes make return visits after as little as a few years or as long as tens of thousands of years.

Compound Telescope
A telescope with a mirror in the back and a lens in the front. The most popular designs are the Schmidt-Cassegrain telescope (SCT) and the Maksutov-Cassegrain telescope (commonly called a “Mak”).

When the Moon or a planet appears especially close either to another planet or to a bright star.

A distinctive pattern of stars used informally to organize a part of the sky. There are 88 official constellations, which technically define sections of the sky rather than collections of specific stars.

The moment when a celestial object crosses the meridian and is thus at its highest above the horizon.

Dark Adaptation
The eyes’ transition to night vision, in order to see faint objects. Dark adaptation is rapid during the first 5 or 10 minutes after you leave a well-lit room, but full adaptation requires at least a half hour — and it can be ruined by a momentary glance at a bright light.

Declination (Dec.)
The celestial equivalent of latitude, denoting how far (in degrees) an object in the sky lies north or south of the celestial equator.

Dobsonian (“Dob”)
A type of Newtonian reflector, made popular by amateur astronomer John Dobson, that uses a simple but highly effective wooden mount. Dobs provide more aperture per dollar than any other telescope design.

Double Star (Binary Star)
Two stars that lie very close to, and are often orbiting, each other. Line-of-sight doubles are a consequence of perspective and aren’t physically related. Many stars are multiples (doubles, triples, or more) gravitationally bound together. Usually such stars orbit so closely that they appear as a single point of light even when viewed through professional telescopes.

Sunlight reflected by Earth that makes the otherwise dark part of the Moon glow faintly. It’s especially obvious during the Moon’s thin crescent phases.

The measure of how much an orbit deviates from being circular.

An event that occurs when the shadow of a planet or moon falls upon a second body. A solar eclipse occurs when the Moon’s shadow falls upon Earth, which we see as the Moon blocking the Sun. When Earth’s shadow falls upon the Moon, it causes a lunar eclipse.

The path among the stars traced by the Sun throughout the year. The Moon and planets never stray far from the ecliptic.

The angular distance the Moon or a planet is from the Sun. The inner planets of Mercury and Venus are best seen when at maximum elongation, and thus are highest above the horizon before sunrise or after sunset.

A timetable with celestial coordinates that indicates where a planet, comet, or other body moving in relation to background stars will be in the sky. Its plural is ephemerides (pronounced eff-uh-MEHR-ih-deez).

The two times each year, near March 20th and September 22nd, when the Sun is directly overhead at noon as seen from Earth’s equator. On an equinox date, day and night are of equal length.

The part of a telescope that you look into. A telescope’s magnification can be changed by using eyepieces with different focal lengths shorter focal lengths yield higher magnifications. Most eyepieces have metal barrels that are 1¼ inches in diameter other standard sizes are 0.965 and 2 inches across.

Field of View
The circle of sky that you see when you look through a telescope or binoculars. Generally, the lower the magnification, the wider the field of view.

A small telescope used to aim your main scope at an object in the sky. Finderscopes have low magnifications, wide fields of view, and (usually) crosshairs marking the center of the field.

Focal Length
The distance (usually expressed in millimeters) from a mirror or lens to the image that it forms. In most telescopes the focal length is roughly equal to the length of the tube. Some telescopes use extra lenses and/or mirrors to create a long effective focal length in a short tube.

Focal Ratio (f/number)
A lens or mirror’s focal length divided by its aperture. For instance, a telescope with an 80-mm-wide lens and a 400-mm focal length has a focal ratio of f/5.

A vast collection of stars, gas, and dust, typically 10,000 to 100,000 light-years in diameter and containing billions of stars (from galaxias kuklos, Greek for “circle of milk,” originally used to describe our own Milky Way).

When the Moon or other body appears more than half, but not fully, illuminated (from gibbus, Latin for “hump”).

A plot of the number of pixels in an image at each brightness level. It’s a useful tool for determining the optimum exposure time the histogram of a properly exposed image generally peaks near the middle of the available brightness range and falls to zero before reaching either end.

The angle between the plane of an orbit and a reference plane. For example, NASA satellites typically have orbits inclined 28° to Earth’s equator.

A slight tipping and tilting of the Moon from week to week that brings various features along the limb into better view. The main causes are two aspects of the Moon’s orbit: its elliptical shape and inclination to the ecliptic.

Light Pollution
A glow in the night sky or around your observing site caused by artificial light. It greatly reduces how many stars you can see. Special light-pollution filters can be used with your telescope to improve the visibility of celestial objects.

The distance that light (moving at about 186,000 miles per second) travels in one year, or about 6 trillion miles.

The edge of a celestial object’s visible disk.

Magnification (power)
The amount that a telescope enlarges its subject. It’s equal to the telescope’s focal length divided by the eyepiece’s focal length.

A number denoting the brightness of a star or other celestial object. The higher the magnitude, the fainter the object. For example, a 1st-magnitude star is 100 times brighter than a 6th-magnitude star.

The imaginary north-south line that passes directly overhead (through the zenith).

Messier object
An entry in a catalog of 103 star clusters, nebulas, and galaxies compiled by French comet hunter Charles Messier (mess-YAY) between 1758 and 1782. The modern-day Messier catalog contains 109 objects.

A brief streak of light caused by a small piece of solid matter entering Earth’s atmosphere at tremendous speed (typically 20 to 40 miles per second). Also called a “shooting star.” If material survives the trip through the atmosphere, it’s called a meteorite after landing on Earth’s surface.

Meteor Shower
An increase in meteor activity at certain times of the year due to Earth passing through a stream of particles along a comet’s orbit around the Sun.

Milky Way
A broad, faintly glowing band stretching across the night sky, composed of billions of stars in our galaxy too faint to be seen individually. It’s invisible when the sky is lit up by artificial light or bright moonlight.

The device that supports your telescope, allows it to point to different parts of the sky, and lets you track objects as Earth rotates. A sturdy, vibration-free mount is every bit as important as the telescope’s optics. A mount’s top, or head, can be either alt-azimuth (turning side to side, up and down) or equatorial (turning parallel to the celestial coordinate system). “Go To” mounts contain computers that can find and track celestial objects automatically once the mounts have been aligned properly.

Latin for “cloud.” Bright nebulas are great clouds of glowing gas, lit up by stars inside or nearby. Dark nebulas are not lit up and are visible only because they block the light of stars behind them.

A telescope’s main light-gathering lens or mirror.

When the Moon or a planet passes directly in front of a more distant planet or star. A grazing occultation occurs if the background body is never completely hidden from the observer.

When a planet or asteroid is opposite the Sun in the sky. At such times the object is visible all night — rising at sunset and setting at sunrise.

The apparent offset of a foreground object against the background when your perspective changes. At a given instant, the Moon appears among different stars for observers at widely separated locations on Earth. Astronomers directly calculate the distance to a nearby star by measuring its incredibly small positional changes (its parallax) as Earth orbits the Sun.

The fraction of the Moon or other body that we see illuminated by sunlight.

Planisphere (Star Wheel)
A device that can be adjusted to show the appearance of the night sky for any time and date on a round star map. Planispheres can be used to identify stars and constellations but not the planets, whose positions are always changing.

Believed to be powered by accretion of material into supermassive black holes in the nuclei of distant galaxies, making these luminous versions of the general class of objects known as active galaxies.

A telescope that gathers light with a mirror. The Newtonian reflector, designed by Isaac Newton, has a small second mirror mounted diagonally near the front of the tube to divert the light sideways and out to your eye.

A telescope that gathers light with a lens. The original design showed dramatic rainbows, or “false color,” around stars and planets. Most modern refractors are achromatic, meaning “free of false color,” but this design still shows thin violet fringes around the brightest objects. The finest refractors produced today are apochromatic, meaning “beyond achromatic.” They use expensive, exotic kinds of glass to reduce false color to nearly undetectable levels.

When an object moves in the reverse sense of “normal” motion. For example, most bodies in the solar system revolve around the Sun and rotate counterclockwise as seen from above (north of) Earth’s orbit those that orbit or spin clockwise have retrograde motion. This term also describes the period when a planet or asteroid appears to backtrack in the sky because of the changing viewing perspective caused by Earth’s orbital motion.

Right Ascension (R.A.)
The celestial equivalent of longitude, denoting how far (in 15°-wide “hours”) an object lies east of the Sun’s location during the March equinox.

A measure of the atmosphere’s stability. Poor seeing makes objects waver or blur when viewed in a telescope at high magnification. The best seeing often occurs on hazy nights, when the sky’s transparency is poor.

Solar Filter
Material that allows safe viewing of the Sun by blocking nearly all of its light. Proper filters should completely cover the front aperture of a telescope and should never be attached to the eyepiece they range from glass used by welders to special plastic film. White-light filters will show sunspots, while hydrogen-alpha (Hα) filters let certain red light through that reveals the Sun’s streaming hot gases.

The two times each year, around June 20th and December 21st, when the Sun is farthest north or south in the sky. At the summer solstice, the day is longest and the night is shortest, and vice versa at the winter solstice.

A massive ball of gas that generates prodigious amounts of energy (including light) from nuclear fusion in its hot, dense core. The Sun is a star.

Star Cluster
A collection of stars orbiting a common center of mass. Open clusters typically contain a few hundred stars and may be only 100 million years old or even less. Globular clusters may contain up to a million stars, and most are at least 10 billion years old (almost as old as the universe itself).

Star Diagonal
A mirror or prism in an elbow-shaped housing that attaches to the focuser of a refractor or compound telescope. It lets you look horizontally into the eyepiece when the telescope is pointed directly overhead.

Star Party
A group of people who get together to view the night sky. Astronomy clubs often hold star parties to introduce stargazing to the public.

A temporary dark blemish on the surface of the Sun that is a planet-size region of gas cooler than its surroundings. Sunspots can be viewed safely using a solar filter.

A star ending its life in a huge explosion. In comparison, a nova is a star that explosively sheds its outer layers without destroying itself.

The line on the Moon or a planet that divides the bright, sunlit part from the part in shadow. It’s usually the most exciting and detailed region of the Moon to view through a telescope.

When Mercury or Venus crosses the disk of the Sun, making the planet visible as a black dot in silhouette, or when a moon passes across the face of its parent planet. Transit also refers to the instant when a celestial object crosses the meridian and thus is highest in the sky.

A measure of the atmosphere’s clarity — how dark the sky is at night and how blue it is during the day. When transparency is high, you see the most stars. Yet crystal-clear nights with superb transparency often have poor seeing.

The time after sunset or before sunrise when the sky is not fully dark. Astronomical twilight ends after sunset (and begins before sunrise) when the Sun is 18° below the horizon.

Unit-Power Finder
A device for aiming your telescope that shows the sky as it appears to your unaided eye, without magnification. The simplest type is a pair of notches or circles that you line up with your target. Other versions use an LED to project a red dot or circle onto a viewing window.

Universal Time (UT)
Greenwich Mean Time, expressed in the 24-hour system. For example, 23:00 UT is 7:00 p.m. Eastern Daylight Time (or 6:00 p.m. Eastern Standard Time). Astronomers use Universal Time to describe when celestial events happen in a way that is independent of an observer’s time zone.

Variable Star
A star whose brightness changes over the course of days, weeks, months, or years.

The changing illumination of the Moon (or other body) over time. The Moon waxes, growing more illuminated, between its new and full phases, and wanes, becoming less illuminated, between its full and new phases.

The changing illumination of the Moon (or other body) over time. The Moon waxes, growing more illuminated, between its new and full phases, and wanes, becoming less illuminated, between its full and new phases.

The point in the sky that’s directly overhead.

Greek for “circle of animals.” It’s the set of constellations situated along the ecliptic in the sky, through which the Sun, Moon, and planets move.

Bolides Astronomy Astronomical Terms

The word bolide is believed to have it’s origins in the Greek word Bolis and has different meanings to different types of scientists. It can refer to a physical object and in that context means “missile”.
It can also mean to flash or go by suddenly. So what actually is a bolide?

The International Astronomy Union can come to no agreement on what it exactly is. Is it a giant meteorite that explodes in a flash of light as it enters the Earth’s atmosphere? Is it maybe a comet, with the gases and such all igniting as crashes into the planet?
It could be either or even both!

To geologists, it refers to a giant crater formed by the impact of a body of extraterrestrial origin, maybe it is alien space craft! At the United States Geological Services website, they used the term bolide “to imply that we do not know the precise nature of the impacting body…whether it is a rocky or metallic asteroid, or an icy comet” ( This definition separates them for geologists from craters of volcanic origin or from known meteorite impacts such as the Sunset Crater in Arizona.

Why are bolides important? Should people be concerned about them? How frequently do they hit the Earth?

Bolides are definitely considered to have originated in outer space and have drastically affected the history of the planet. Some people believe bolides were responsible for the current shape of the continents and for several of the mass extinctions that have occurred in the past. Dinosaurs are believed to have been victims of a bolide.

The National Aeronautics and Space Administration has for the last several years been cataloguing space objects that could impact the Earth and cause problems in the future. They will identify them and hopefully find ways to alter their paths, preventing the death and destruction bolides have caused in the path.

Of course, this can create a problem as once they identify and approaching object, prevent it from hitting the planet, it is no longer technically a bolide. Bolides are unidentified objects that flash and form craters, remember! They are like a UFO, if you can identify it it is no longer unidentified and no longer a UFO. Identifying a bolide, which is also unknown, witll no longer make it unknown.

Maybe that is what bolides actually are! They are crashing alien spaceships from other planets that dematerialize upon impact.
Why haven’t the scientists thought of that!

2021 Astronomical Calendar: Full Moons, Meteor Showers, and Eclipses to Watch for This Year

This 2021 astronomical calendar has every full moon, meteor shower, and eclipse to look forward to this year.

From the great conjunction to impressive comets, 2020 was filled with exciting astronomical events, but there’s even more on the horizon (and in the night sky) for 2021. This year, stargazers can look forward to meteor showers, lunar eclipses, supermoons, and even a total solar eclipse. To help you keep track of them all, we’ve created this astronomical calendar with some of 2021’s celestial highlights, thanks to information gathered from NASA, the American Meteor Society, and The Old Farmer’s Almanac. 

Before planning your year of stargazing, there are a few basic things to know about each of these events. You’ve probably seen numerous full moons during your lifetime, but do you know what a supermoon is? Supermoons happen when the full moon occurs at perigee — the point at which the moon appears closest to the Earth in its orbit. Full moons and supermoons are easy to spot wherever you are, but you might want to head somewhere with less light pollution for the best chance of seeing shooting stars during a meteor shower.

Lunar eclipses and solar eclipses are only visible in certain parts of the world — and this year’s total solar eclipse can only be seen in Antarctica.

Want to take your stargazing to the next level? Invest in a telescope or good binoculars, so you can see even more in the night sky. 

Below, find the dates of every full moon (including two supermoons), two solar eclipses, two lunar eclipses, and five major meteor showers in 2021. (Note that the below dates are according to UT, and that we’ve listed the predicted maximum of the meteor showers. For some of these showers, you might be able to spot a few shooting stars before and after that date.)

Astronomy and related astronomical terms

Astronomy is concerned with the positions, motions, distances, and physical conditions and with the origins and evolution of the celestial bodies which were mentioned previously.

It is divided into such areas as astrophysics, celestial mechanics, and cosmology and it is one of the oldest recorded sciences with observational records from ancient Babylonia, China, Egypt, and Mexico.

Remarkable recent extensions of the powers of astronomy to explore the universe is in the use of rockets, satellites, space stations, and space probes while the launching of the Hubble Space Telescope into permanent orbit in 1990 enabled the detection of celestial phenomena seven times more distant than by any earth-based telescope.

The development of astronomy can be divided into four primary periods

  1. Ancient astronomy, dating from the first significant contributions of the earliest civilizations to the Almagest of Ptolemy.
  2. Medieval astronomy, from the decline of Alexandrian culture to the Renaissance.
  3. Modern astronomy, from the Copernican revolution to the present time.
  4. The new astronomy of astrophysics, primarily a product of the 20th century.

Astronomy is the science of the celestial bodies such as, the sun, the moon, and the planets the stars and galaxies and all of the other objects in the universe.

Astronomy is concerned with their positions, motions, distances, and physical conditions as well as, with their origins and evolutions.

Astronomy deals with the origin, evolution, composition, distance, and motion of all bodies and scattered matter in the universe.

Astronomy is considered to be the oldest recorded science because there are records which can be examined from ancient Babylonia, China, Egypt, and Mexico.

As far as we can determine, the Greeks were the first "true astronomers" because they deduced that the earth was a sphere and they attempted to measure its size. A summary of Greek astronomy can be found in Ptolemy of Alexandria's Almagest which contains nearly all that is known of the astronomical observations and theories of the ancients.

The Almagest is also described as being a text on astronomy written by Ptolemy in the second century A.D. setting out his view of the universe with the earth at its center surrounded by spheres.

Ptolemy’s model of an earth-centered universe influenced astronomical thought for over 1,300 years.

In 1543, the Polish astronomer Copernicus demonstrated that the sun, not the earth is the center of our planetary system and the Italian scientist, Galileo, was the first to use a telescope for astronomical study, in 1609-1610.

The 17th century saw several momentous developments such as, Johannes Kepler's discovery of the principles of planetary motion, Galileo's application of the telescope to astronomical observation, and Isaac Newton's formulation of the laws of motion and gravitation.

The most remarkable recent extension of the powers of astronomy to explore the universe is in the use of rockets, satellites, space stations, and space probes while the launching of the Hubble Space Telescope into permanent orbit in 1990 has enabled the detection of celestial phenomena seven times farther than by any earth-based telescope.

—Compiled from information located in "Astronomy", Encyclopædia Britannica
Retrieved, May 09, 2010, from Encyclopædia Britannica Online .

"Astronomy", Scientific American Science Desk Reference John Wiley and Sons, Inc.: New York 1999 page 165

"History of Astronomy", Encyclopaedia Britannica William Benton, Publisher Chicago 1968 pages 643-655.

The first successful photograph of a celestial object was the daguerreotype plate of the moon taken by John W. Draper (1811-1882) of the United States in March, 1840.

The first photograph of a star, Vega, was taken by U.S. astronomer William C. Bond (1789-1859) in 1850. Modern-day astrophotography now uses techniques such as, charge-coupled devices (CCDs) forming images electronically.

Its brightest star is the first-magnitude Capella, about 45 light-years from Earth. Epsilon Aurigae is an eclipsing binary star with a period of 27 years, the longest of its kind.

Although aurorae are usually restricted to the polar skies, fluctuations in the solar wind occasionally cause them to be visible at lower latitudes.

Aurorae are caused at heights of over 100 kilometers or 60 miles by a fast stream of charged particles from solar flares and low-density "holes" in the sun's corona.

Caused by the interaction between the solar wind, the earth's magnetic field and the upper atmosphere.

A similar effect happens in the southern hemisphere where it is known as the aurora australis.

2. "Northern lights" or colored lights in the night sky near the earth's magnetic pole in the northern hemisphere of the earth.

The effect occurs when bits of photosphere shine through valleys at the moon's edge.

Named after Francis Baily (1774-1844), a British astronomer.

Johann Bayer was a German lawyer and uranographer (celestial cartographer or someone who maps stars, galaxies, and other celestial bodies). He is most famous for his star atlas Uranometria , published in 1603, which was the first atlas to cover the entire celestial sphere.

It introduced a new system of star designation which has become known as the "Bayer designation". It introduced twelve new constellations to fill in the far south of the sky, which was unknown to ancient Greece and Rome.

According to the theory, at the time of the Big Bang, the entire universe was squeezed into a hot, superdense state and the explosion threw the compact material outward, producing the expanding universe.

Wise men looking to the skies

Molnar believes that the wise men were, in fact, very wise and mathematically adept astrologers. They also knew about the Old Testament prophecy that a new king would be born of the family of David. Most likely, they had been watching the heavens for years, waiting for alignments that would foretell the birth of this king. When they identified a powerful set of astrological portents, they decided the time was right to set out to find the prophesied leader.

If Matthew’s wise men actually undertook a journey to search for a newborn king, the bright star didn’t guide them it only told them when to set out. And they wouldn’t have found an infant swaddled in a manger. After all, the baby was already eight months old by the time they decoded the astrological message they believed predicted the birth of a future king. The portent began on April 17 of 6 BC (with the heliacal rising of Jupiter that morning, followed, at noon, by its lunar occultation in the constellation Aries) and lasted until December 19 of 6 BC (when Jupiter stopped moving to the west, stood still briefly, and began moving to the east, as compared with the fixed background stars). By the earliest time the men could have arrived in Bethlehem, the baby Jesus would likely have been at least a toddler.

Matthew wrote to convince his readers that Jesus was the prophesied Messiah. Given the astrological clues embedded in his gospel, he must have believed the story of the Star of Bethlehem would be convincing evidence for many in his audience.

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Elementary Lectures

The following courses provide a descriptive knowledge of astronomical objects and astrophysics. PHYSICS 15 , PHYSICS 16 , and PHYSICS 17 are for students not majoring in the sciences and are taught in different quarters by different instructors, and may be taken individually or in any order.

Course List
PHYSICS 15Stars and Planets in a Habitable Universe3
PHYSICS 16The Origin and Development of the Cosmos3
PHYSICS 17Black Holes and Extreme Astrophysics3


The following courses allow students to use the on-campus Stanford Student Observatory, and are intended to familiarize students with observational methods and analysis of astronomical data. PHYSICS 50 is for general students, while PHYSICS 100 involves more advanced observations and is intended for students with a college level background in physics.

Course List
PHYSICS 50Astronomy Laboratory and Observational Astronomy3
PHYSICS 100Introduction to Observational Astrophysics4

Advanced Undergraduate

The following courses are for students with a more advanced knowledge of basic physics and mathematics, and form the core courses for a concentration in astrophysics for Physics majors.

Course List
PHYSICS 160Introduction to Stellar and Galactic Astrophysics3
PHYSICS 161Introduction to Cosmology and Extragalactic Astrophysics3


Course List
PHYSICS 260Introduction to Stellar and Galactic Astrophysics3
PHYSICS 261Introduction to Cosmology and Extragalactic Astrophysics3
PHYSICS 262General Relativity3
PHYSICS 269Neutrinos in Astrophysics and Cosmology3
PHYSICS 301Astrophysics Laboratory (Not offered 2020-21)3
PHYSICS 312 (Not offered 2020-21)3
PHYSICS 361Cosmology and Extragalactic Astrophysics (Not offered 2020-21)3
PHYSICS 362The Early Universe (Not offered 2020-21)3
PHYSICS 366Statistical Methods in Astrophysics2
PHYSICS 368 (Not Offered 2020-21)2

Emeriti: (Professors) Peter A. Sturrock, G. Leonard Tyler, Robert V. Wagoner

Professors: Tom Abel (Physics, SLAC), Steve Allen (Physics, SLAC), Roger Blandford (Physics, SLAC), Pat Burchat (Physics), Blas Cabrera (Physics), Sarah Church (Physics), Kent Irwin (Physics, SLAC), Steven Kahn (Physics, SLAC), Chao-Lin Kuo (Physics, SLAC), Bruce Macintosh (Physics), Peter Michelson (Physics), Vahé Petrosian (Physics, Applied Physics), Roger W. Romani (Physics), Risa Wechsler (Physics, SLAC)

Astronomical Term *Mezzocielo* - Astronomy

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Mezzocielo: an attempt to redesign the concept of wide field telescopes

R. Ragazzoni, 1,2,3 M. Dima, 1,3 C. Arcidiacono, 1,3 D. Magrin, 1,3 S. Di Rosa, 2 S. Zaggia 1

1 INAF - Osservatorio Astronomico di Padova (Italy)
2 Univ. of Padova (Italy)
3 ADaptive Optics National Lab. (Italy)


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Mezzocielo (or "half of the sky") is a concept for a new class of telescopes where a full spherical optical surface is made by filling with a liquid a structure built up with spherical lenses and almost covering an entire sphere. Lenses of the same class of existing ones can be arranged, for example like the faces of a dodecahedron, in order to build up a sphere in the 1 to 4m class in diameter. Liquid with low refractive index and high transparency are available in the electronic and cooling industry and made up devices with strong high order spherical aberrations but consistently identical over basically any direction in the sky simultaneously. An ensemble of moving correctors or a hemispherical array of the same kind of devices can feed a number of detectors lying in the range of the ten of thousands, making modern CMOS the only, today, viable solution to such a kind of futuristic facility.

© (2020) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Astronomy is our hobby! Dedicated to the fun of astronomy at all levels from beginner to expert, casual viewing to scientific research. We welcome everyone interested in astronomy. Find out more about us.

MAS General Meetings
All MAS meetings at the Observatory are CANCELED.
We still have meetings, but the are for Our members and done via Zoom video.

Public Open House
Due to the COVID-19 situation, our Public Nights at the observatory for 2021 have been delayed until September. Tentatively, our first open house is on September 10th.

MAS Observatory occupies 3 acres at 18850 W Observatory Rd in New Berlin, WI 53146

We are pleased to announce we have established a tentative Open House schedule for this year. Please check back in the coming months for possible changes.

September 10, 7:00-10:00PM

October 1, 6:30-9:30PM

October 29, 6:00-9:00PM

For sky updates:

Other Terms — Otros términos

albedo — el albedo
astronaut — el/la astronauta
astronomy — la astronomía
Big Bang — el Big Bang, la gran explosión
crater — el cráter
dark matter — la materia oscura
eclipse — el eclipse
full moon — el plenilunio, la luna llena
gravitational field — el campo gravitatorio
gravity — la gravedad
light year— al año luz (los años luz in plural)
magnetic field — el campo magnético
new moon — la luna nueva
nuclear fusion — la fusión nuclear
orbit — la órbita
red shift — el corrimiento al rojo, el desplazamiento hacia el rojo
revolution — la revolución
solar flare — la erupción solar
spacecraft — la nave espacial
space probe — la sonda espacial
space shuttle — el transbordador espacial, la lanzadera espacial
space station — la estación espacial
telescope — el telescopio
theory of relativity — la teoría de la relatividad
twinkling (of stars) — el centellear
vacuum of space — el vacío del espacio
wormhole — el agujero de gusano (This is an example of a calque.)
zodiac — el zodiaco, el zodíaco