Astronomy

Catalog of Galaxies in the Visible Universe

Catalog of Galaxies in the Visible Universe


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I have seen the Gaia project from here which is about mapping the stars in the Milky Way galaxy. But I'm wondering if there is any open data on the positions (or something like "positions" since it probably not calculable now), or "coordinates", of the galaxies in the visible universe, as opposed to the stars. I wonder how animations such as this (a time=1m30s point it shows the galaxies zooming out from the Milky Way) get their data on the positions of the galaxies.


There are lots of galaxy catalogs.

If you're only interested in nearby galaxies, there are things like the Updated Nearby Galaxy Catalog; downloadable versions can be found here.

A classic all-sky galaxy catalog is the Third Reference Catalogue of Bright Galaxies (RC3, published in the early 1990s), which you can query here; if you follow the "FTP" links, you can find links to download the actual catalog.

(The HyperLEDA catalog that Dr. Chuck mentioned started as the RC3, but has various bits of data and re-classifications added more or less continuously since.)

A more recent catalog, based on the near-infrared observations of the 2 Micron All-Sky Survey (2MASS) is the 2MASS Galaxy Redshift Catalog, with about one million galaxies.

Even larger catalogs (though not covering the whole sky) can be found among the data products of the Sloan Digital Sky Survey, e.g. here

Many more catalogs exist, though some do not have accurate redshift information (meaning their distance from us is unknown or uncertain), and many are only for parts of the sky, sometimes very small regions (e.g., catalogs from Hubble Space Telescope observations).

(As for that video, I suspect very little is based on real data once you get beyond the Andromeda Galaxy… )


There is the Uppsala General Catalog of Galaxies

It has galaxies down to 19 magnitude. It doesn't have distances, but it does have radial velocity.


There is the HyperLeda catalog http://leda.univ-lyon1.fr/, which has about 5 million galaxies, with redshift for about 3 million (if I understand the summary).


Largest ever map of the universe's dark matter is released

The light of 100 million galaxies was analysed to come up with the plot, which covers a quarter of the southern hemisphere's sky.

Friday 28 May 2021 06:02, UK

The largest ever map of the universe's dark matter has been released.

Dark matter, which is unobservable from the Earth, is thought to make up around 80% of matter in the universe.

A team of scientists from the international Dark Energy Survey (DES) created the new map - which covers a quarter of the southern hemisphere's sky.

They did it by looking at how light from far away galaxies has been distorted on its way to Earth.

The presence of dark matter would bend the rays coming towards us.

Artificial intelligence analysed the data to create the map.

About 100 million galaxies were observed for the project. According to NASA, there are 100 billion stars in the Milky Way alone.

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The DES team was led by researchers from University College London.

Dr Niall Jeffrey, from UCL's physics and astronomy department, was one of the lead authors on the project.

He said: "Most of the matter in the universe is dark matter. It is a real wonder to get a glimpse of these vast, hidden structures across a large portion of the night sky.

"These structures are revealed using the distorted shapes of hundreds of millions of distant galaxies with photographs from the Dark Energy Camera in Chile.

"In our map, which mainly shows dark matter, we see a similar pattern as we do with visible matter only, a web-like structure with dense clumps of matter separated by large empty voids.

"Observing these cosmic-scale structures can help us to answer fundamental questions about the universe."

Dark matter's existence can be inferred from the way galaxies move - they stay together and those in clusters move faster than expected.

Another of the paper's author's, Professor Ofer Lahav, chairman of the DES UK consortium and also a member of the UCL Physics and Astronomy team said: "Visible galaxies form in the densest regions of dark matter.

"When we look at the night sky, we see the galaxy's light but not the surrounding dark matter, like looking at the lights of a city at night.

"By calculating how gravity distorts light, a technique known as gravitational lensing, we get the whole picture, both visible and invisible matter.

"This brings us closer to understanding what the universe is made of and how it has evolved.

"It also shows the power of artificial intelligence methods to analyse one of the largest data sets in astronomy."

Research from DES has supported the standard cosmological model of how the universe works.


Dark matter map shows hidden ‘bridges’ connect galaxies

You are free to share this article under the Attribution 4.0 International license.

A new map of dark matter in the local universe reveals several previously undiscovered filamentary structures connecting galaxies.

The map, developed using machine learning, could enable studies about the nature of dark matter as well as about the history and future of our local universe.

“Having a local map of the cosmic web opens up a new chapter of cosmological study.”

Dark matter is an elusive substance that makes up 80% of the universe. It also provides the skeleton for what cosmologists call the cosmic web, the large-scale structure of the universe that, due to its gravitational influence, dictates the motion of galaxies, and other cosmic material. However, the distribution of local dark matter is currently unknown because it cannot be measured directly. Researchers must instead infer its distribution based on its gravitational influence on other objects in the universe, like galaxies.

“Ironically, it’s easier to study the distribution of dark matter much further away because it reflects the very distant past, which is much less complex,” says Donghui Jeong, associate professor of astronomy and astrophysics at Penn State and a corresponding author of the study. “Over time, as the large-scale structure of the universe has grown, the complexity of the universe has increased, so it is inherently harder to make measurements about dark matter locally.”

The map of the dark matter within the local universe, which researchers created using a model to infer its location due to its gravitational influence on galaxies (black dots). These density maps—each a cross section in different dimensions—reproduce known, prominent features of the universe (red) and also reveal smaller filamentary features (yellow) that act as hidden bridges between galaxies. The X denotes the Milky Way galaxy and arrows denote the motion of the local universe due to gravity. (Credit: Hong et. al., Astrophysical Journal)

Previous attempts to map the cosmic web started with a model of the early universe and then simulated the evolution of the model over billions of years. However, this method is computationally intensive and so far has not been able to produce results detailed enough to see the local universe.

In the new study, the researchers took a completely different approach, using machine learning to build a model that uses information about the distribution and motion of galaxies to predict the distribution of dark matter.

The researchers built and trained their model using a large set of galaxy simulations, called Illustris-TNG, which includes galaxies, gasses, other visible matter, as well as dark matter. The team specifically selected simulated galaxies comparable to those in the Milky Way and ultimately identified which properties of galaxies are needed to predict the dark matter distribution.

“When given certain information, the model can essentially fill in the gaps based on what it has looked at before,” says Jeong. “The map from our models doesn’t perfectly fit the simulation data, but we can still reconstruct very detailed structures. We found that including the motion of galaxies—their radial peculiar velocities—in addition to their distribution drastically enhanced the quality of the map and allowed us to see these details.”

The research team then applied their model to real data from the local universe from the Cosmicflow-3 galaxy catalog. The catalog contains comprehensive data about the distribution and movement of more than 17 thousand galaxies in the vicinity of the Milky Way—within 200 megaparsecs.

The resulting map of the local cosmic web will appear in a paper in the Astrophysical Journal.

The map successively reproduced known prominent structures in the local universe, including the “local sheet”—a region of space containing the Milky Way, nearby galaxies in the “local group,” and galaxies in the Virgo cluster—and the “local void”—a relatively empty region of space next to the local group. Additionally, it identified several new structures that require further investigation, including smaller filamentary structures that connect galaxies.

“Having a local map of the cosmic web opens up a new chapter of cosmological study,” says Jeong. “We can study how the distribution of dark matter relates to other emission data, which will help us understand the nature of dark matter. And we can study these filamentary structures directly, these hidden bridges between galaxies.”

For example, it has been suggested that the Milky Way and Andromeda galaxies may be slowly moving toward each other, but whether they may collide in many billions of years remains unclear. Studying the dark matter filaments connecting the two galaxies could provide important insights into their future.

“Because dark matter dominates the dynamics of the universe, it basically determines our fate,” says Jeong. “So we can ask a computer to evolve the map for billions of years to see what will happen in the local universe. And we can evolve the model back in time to understand the history of our cosmic neighborhood.”

The researchers believe they can improve the accuracy of their map by adding more galaxies. Planned astronomical surveys, for example using the James Web Space Telescope, could allow them to add faint or small galaxies that have yet to be observed and galaxies that are further away.

Additional researchers are from the University of Seoul/Korea Astronomy and Space Science Institute, the Seoul National University, and the Korea Institute for Advanced Study. This research was supported in part by the National Research Foundation of Korea funded by the Korean Ministry of Education, the Korean Ministry of Science, the US National Science Foundation, the NASA Astrophysics Theory program, and the Center for Advanced Computation at the Korea Institute for Advanced Study.


To find out how galaxies grow, we're zooming in on the night sky and capturing cosmic explosions

Credit: Sara Webb, Author provided

Across Australia, astronomers are using cutting-edge technologies to capture the night sky, hoping to eventually tackle some of our biggest questions about the universe.

As we and our colleagues delve deeper into the cosmos, looking for cosmic explosions, our observations are helping shed light on longstanding mysteries—and making way for entirely new paths of inquiry.

Cosmic eruptions fill the sky

Swinburne's Deeper, Wider, Faster (DWF) program—which one of us (Sara Webb) worked on throughout her Ph.D.—was developed to hunt for the fastest and most mysterious explosions in the universe.

But to understand what causes cosmic explosions, we must "look" at these events with multiple eyes, through different telescopes around the world. Today we'll take you on a journey using data from one of these telescopes, the Blanco 4m, at Chile's Cerro Tololo Inter-American Observatory.

First, all 60+ individual images taken of the field of view from this telescope are combined into a mosaic. Within them we see the thousands of bright sources.

These images are transferred across the Pacific to be processed on Swinburne's OzStar supercomputer—which is more powerful than 10,000 personal laptops and can handle thousands of different jobs at once.

This is an example of dark energy camera data taken by the DWF program. This image is of an enormous section of the sky. Credit: Sara Webb

Once uploaded, the images are broken down into smaller chunks. This is when we start to see details.

But the galaxies above, spectacular as they are, still aren't what we're looking for. We want to capture new "sources" resulting from dying stars and cosmic explosions, which we can identify by having our computers search for light in places it wasn't previously detected.

A source could be many different things including a flaring star, a dying star or an asteroid. To find out we have to collect continuous information about its brightness and the different wavelengths of light it emits, such as radio, X-ray, gamma-ray and so forth.

Once we spot a source, we monitor changes in its brightness over the coming hours and days. If we think it may represent a rare cosmic explosions, we trigger other telescopes to collect additional data.

Pictured are some of the galaxies visible within smaller cutouts of data sent to the DWF program from the Blanco 4 m. Credit: Sara Webb

Peering into the distant past

Galaxies are vast collections of stars, gas, dust and dark matter. They vary in shape, size and color, but the two main types we see in the universe today are blue spirals and red ellipticals. But how do they form? And why are there different types?

Astronomers know the shapes and colors of a galaxy are linked to its evolution, but they're still trying figure out exactly which shapes and colors are linked to specific growth pathways.

We think galaxies grow in size and mass through two main channels. They produce stars when their vast hydrogen clouds collapse under gravity. As more gas is transformed into stars, they grow in size.

Thanks to space-based technology such as the Hubble Space Telescope and powerful on-ground telescopes, astronomers can now peer back in time to study galaxy growth over the history of the universe.

To the left is an old image of a patch of sky and to the right is a updated image with a new source having just occurred. This one is likely a flare star or an asteroid. Credit: Sara Webb

This is possible since the further away a galaxy is, the longer its light traveled to reach us. Because the speed of light is constant, we can determine when the light was emitted—as long as we know the galaxy's distance from Earth (called its "redshift").

I measured this growth as part of my Ph.D., by taking images of galaxies that exist at different redshifts from as far back as when the universe was only one billion years old, and comparing their sizes.

Looking around the universe today, we mostly see galaxies clustered together. Astronomers believe the nature of a galaxy's surroundings or its environment can affect its growth pathways, similar to how people in large cities can access more resources than those in rural areas.

When many galaxies are grouped together they may interact. And this interaction can stimulate bursts of star formation within a particular galaxy.

A selection of distant galaxies spotted in my study of galaxy growth over time. These appear very different to nearby galaxies. Credit: Rebecca Allen

That said, this growth spurt may be short-lived, as gas and stars can be stripped away through the gravitational interaction between multiple galaxies, thereby limiting future star formation and growth in a single galaxy.

But even if a galaxy can't form stars, it can still grow by merging with or consuming smaller galaxies. For example, the Milky Way will one day consume the smaller Magellanic clouds, which are dwarf galaxies. It will also merge with the slightly larger Andromeda galaxy one day, to form one giant galaxy.

Yet, while many studies have been conducted unpack galaxy evolution, we still can't say all our questions have been answered.

It took billions of years for the galaxy clusters we observe today to form. But if astronomers can leverage the latest technologies and peer further into the distance than ever before, we will hopefully gain clues about how a galaxy's environment can impact its growth.

This image was captured using the Hubble Space Telescope. It shows a group of spiral galaxies, which astronomers can clearly determine due to the high resolution of the image. Credit: Rebecca Allen

The bending of spacetime reveals secrets

With decades of observations and millions of galaxies captured in surveys, experts have many theories regarding how galaxies form, and how the universe evolves. This field is called cosmology.

Thanks to Albert Einstein, we know the gravitational force of massive objects in space causes space to bend. This has been observed through a phenomena known as "lensing," where vast amounts of matter are concentrated in one area within objects such as black holes, galaxies or galaxy clusters.

Their gravity distorts spacetime, acting as a giant lens to reveal warped images of more distant objects behind them. Using lensing, astronomers have developed ways to find and study distant galaxies that would otherwise be hidden from view.

These observations continue to drive our understanding of galaxy evolution. They're challenging our theories of when and how galaxies form and grow.

  • Pictured are two groups of distant galaxies that existed when the universe was one-quarter of its current age. These galaxy groups will eventually come together and form a structure similar to the Virgo cluster. I have studied them both to learn more about how the galaxies within them are growing. Credit: Rebecca Allen
  • A set of galaxy-galaxy lenses. The massive foreground galaxy’s gravity distorts spacetime, acting as a lens that reveals a warped image of a distant background galaxy. Credit: Rebecca Allen
  • One of the massive quiescent galaxies which our team will investigate. While extremely large, its older stars and distance make it appear as a tiny red nugget among the much brighter and closer galaxies. Credit: Rebecca Allen, Author provided

One 2018 discovery made by a group of researchers, including myself, revealed a set of massive and already evolved galaxies from when the universe was only about one-sixth of its current age. They would have had to form and grow at an extremely rapidly to fit our current models of galaxy growth.

In an upcoming investigation, Swinburne Professor Karl Glazebrook will lead me and my team to become some of the first astronomers granted access to Nasa's James Webb Space Telescope to study these early galaxies.

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


Section III - Universe Pictures of Star Outbursts

V838 Monocerotis

Image Credit: NASA, ESA and H.E. Bond (STScI).

In January 2002, V838 Monocerotis, which had hitherto been a dull star, suddenly became 600,000 times more luminous than our Sun and its outer surface seemed to expand greatly making it the brightest star in the entire Milky Way Galaxy for several weeks. As the light from the flash traveled through the Universe, it progressively illuminated the previously invisible shells of dust surrounding the mysterious star. This created an illusion that the star itself was expanding. This phenomenon is called a "light echo." The star is a red variable star located about 20,000 light-years away from the Earth in the direction of the Monoceros (or Unicorn) constellation. It has now faded back to obscurity. The reason for its outburst still continues to puzzle astronomers. The above picture of the star is one of the most amazing Universe pictures taken by the Hubble Space Telescope.


"Invisible" Galaxies Found in the Young Universe

By: Monica Young August 12, 2019 9

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Astronomers have discovered galaxies that have escaped detection until now, uncovering a missing link in galaxy evolution. The find suggests that we don’t understand galaxy formation as well as we thought we did.

In deep observations that dig into the earliest eras of the universe, astronomers have excavated the ancestors of modern-day massive galaxies. These dusty galaxies are bursting with stars — but they’re invisible at the wavelengths astronomers typically probe.

ALMA identified 39 faint galaxies that are not seen with the Hubble Space Telescope’s deepest view of the Universe 10 billion light-years away. This example image shows a comparison between Hubble and ALMA observations. The squares numbered from 1 to 4 are the locations of faint galaxies unseen in the Hubble image.
University of Tokyo / CEA / NAOJ

Astronomers have spent years observing a small window of sky with the Hubble and Spitzer Space Telescopes, among other facilities. The survey, dubbed Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), samples hundreds of thousands of galaxies at cosmic dawn — when galaxies first appeared — through cosmic noon, when most of the stars we see today formed. Now, a new study published in the August 7th Nature reveals a couple dozen galaxies emitting submillimeter-wavelength radiation. They represent a missing link in galaxy evolution.

Tao Wang (University of Tokyo, French Alternative Energies and Atomic Energy Commission, and the National Astronomical Observatory of Japan) and colleagues focused on 63 infrared-bright galaxies detected in the CANDELS field. Although the Spitzer Space Telescope had detected infrared radiation from these sources, they disappear when viewed through near-visible wavebands. (Specifically, the galaxies go dark beginning with the H-band filter, which is centered at 1,650 nanometers.) Wang and his team observed each galaxy using the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile. They made bank on 39 of them, detecting those galaxies at submillimeter wavelengths.

The ALMA observations show that these optically invisible galaxies are bursting with new stars, forming at roughly 200 times the rate in the Milky Way. But these newborn stars are so heavily shrouded in dust they’re invisible except at very long wavelengths.

That leaves a question, muses Allison Kirkpatrick (University of Kansas), an expert in galaxy evolution who was not involved in the study: Where did all this dust come from?

The Dust’s the Thing

The Herschel Space Observatory and the Hubble Space Telescope imaged Supernova 1987A at longer (left) and shorter (right) wavelengths, respectively. The Herschel image reveals infrared and submillimeter light, showing the dust that formed among the supernova's remains.
ESA / NASA-JPL / UCL / STScI

The newly discovered galaxies reside in the universe between 1 billion and 3 billion years after the Big Bang, a time between “dawn” and “noon” (a cosmic elevenses, if you will). During this time, star formation was ramping up across the cosmos, and starbirth also means stardeath. Dust forms in the aftermath of supernova explosions but, Kirkpatrick notes, astronomers didn’t think there would have been enough supernovae to produce so much dust so soon.

Since astronomers weren’t expecting dust, they weren’t expecting “invisible” galaxies. Newborn stars are brightest at ultraviolet wavelengths, but the expanding universe will stretch the wavelengths of photons from more distant galaxies. A galaxy might appear bright at optical or even near-infrared wavelengths if it’s far enough away. Regardless, if there’s no dust, then we should be able to see galaxies near and far using just ultraviolet, optical, and near-infrared wavelengths.

Observations at submillimeter wavelengths had turned up galaxies before now, but these had been the extreme stellar factories churning out thousands of stars per year. Those galaxies, while fascinating, are rare. The dim, shrouded galaxies that Wang’s team saw, though, are common enough that they could represent the ancestors of massive, elliptical galaxies that we see in today’s universe.

Results such as this one, though, suggest that the young universe is more dusty than we thought. “This means we do not understand star formation in the early universe,” says Kirkpatrick. “Theory is, as of this paper, based on outdated observations.”

Our understanding of galaxy formation, it seems, is up for major revision.


Modern Astronomy

What is so special about modern astronomy and cosmology is how key features of the galaxy assembly can be made apparent. The equipment is able to capture and reveal galaxies in the visible light, as well as the ultraviolet to the near-infrared part of the spectrum. The wavelength spans the entire range. For example, cosmic dust and gas are normally not always visible unless they illuminated by nearby stars.

Catalog lead researcher Katherine Whitaker of the University of Connecticut, in Storrs, said:

“Such exquisite high-resolution measurements of the numerous galaxies in this catalog enable a wide swath of extragalactic study. Often, these kinds of surveys have yielded unanticipated discoveries which have had the greatest impact on our understanding of galaxy evolution.”

This wider view contains about 30 times as many galaxies as the previous deep fields. The Legacy Field has also revealed several unusual objects. Many are the remnants of collisions and mergers that took place during the early Universe – what are referred to as galactic “train wrecks”. It is the most detailed and expansive image of galaxies ever taken.


3-D Map Of Universe Shows Positions Of Known Galaxies In Unprecedented Detail (VIDEO)

Still trying to find your place in the world? How about the universe?

An international team of astronomers and astrophysicists have created a video spotlighting their new 3-D map of the known universe. The map was created from a collection of galaxy redshifts -- observations of light emitted from galaxies as they move away from the earth.

"In terms of moving -- pardon the pun -- pictures, this is by far the best I have seen among numerous motion pictures showing where we are at, literally and figuratively, in the biggest picture of all," Ian Steer, co-leader of the NASA/IPAC Extragalactic Database of galaxy Distances, commented on the video on Vimeo.

As seen in the video, the map shows the location of all the visible galaxies in our universe as far away as 340 million light-years.

Impressive, for sure. But as it turns out , that's only a fraction of the universe.

“We actually don’t know how big the whole universe is,” Dr. R. Brent Tully, astronomer at the Institute for Astronomy in Honolulu, Hawaii, told the Los Angeles Times. “What we talk about is the universe within our horizon, the travel time of light, and that’s been traveling to us since 14 billion years."

So how far is this map's reach into the universe? "Tiny. About 1 part in 100 million of the universe within our horizon," Dr. Tully told The Huffington Post in an email.

But this map is just the beginning. According to Dr. Tully, "This first video is really just a test of possibilities. We already have data in hand to extend the maps to 600 million light years at all three levels."

Watch the video here:

The video was presented at the "Cosmic Flows -- Observations and Simulations" conference. A paper about the video has been submitted to the Astronomical Journal and can be read here.

CORRECTION: A previous version of this post misstated Ian Steer's job title. We regret the error.


Counting Galaxies in the Universe By Their Dark Matter Halos

There is no hard-set limit on the smallest number of stars that can make up a galaxy (dwarf galaxies might host as few as a thousand stars, whereas star clusters orbiting galaxies can contain more than a million). The distinction lies in dark matter halos: galaxies and dwarf galaxies have them, while star clusters do not.

So to estimate how many galaxies we could theoretically observe, we would want to know the number of dark matter halos in the observable universe, and the probability that any halo with a certain mass would form stars, explains Henry Ferguson (Space Telescope Science Institute). Currently, there is no consensus on these values, but estimating the galactic population with this method could result in a number much higher than 225 billion.

Did you know that a supermassive black hole lurks in almost every large galaxy? Learn more about the billions of behemoths that exist in our observable universe in Sky & Telescope's free Black Holes ebook. E nter your email to join the Sky & Telescope newsletter and download the ebook for FREE.


Astronomical Work for an Amateur's Catalog

By: Diana Hannikainen December 21, 2018 0

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Amateur astronomer Rick Johnson undertook the monumental task of building his own observatory and compiling a catalog of objects he has observed.

Astronomical catalogs have been in existence ever since the Sumerians first began recording celestial phenomena on cuneiform tablets around 3500 BC. Most subsequent civilizations kept records of their observations, which focused largely on planetary risings and settings, lunar cycles, solar eclipses, primarily for calendar-keeping purposes — it helped to know when to plant seed or when to harvest. Cataloging this information was the most efficient way of keeping track of events not only from year to year, but mainly from generation to generation.

With the advent of the telescope opening up access to much more of the visible universe, catalogs were essential for documenting the growing number of objects and categorizing them by their nature. One of our more famous catalogs blossomed out of Charles Messier’s frustration at fuzzy objects distracting him from his main focus, that of hunting for comets.

Astronomers have come to rely heavily on catalogs and today we have catalogs dedicated to single stars, double stars, galaxies, globular clusters, catalogs for X-ray sources and radio sources, you name it. Accuracy is paramount in the compiling of catalog data, and the task is daunting, the fruit of the labors of large teams of researchers. Take, for example, the latest release of the Gaia catalog that counts some 1,692,919,135 entries.

But you don’t need to be a professional astronomer to get involved in catalog-making. Just ask Rick Johnson.

A New Kind of Catalog

According to Jack Dunn, Rick Johnson is a "virtual Renaissance Man and closely resembles Santa Claus in the winter."
Jack Dunn

Rick, a founding member of the Prairie Astronomy Club of Lincoln, Nebraska, had his passion in astronomy sparked when, as a small child, he witnessed a total lunar eclipse in September 1950. He started out, like so many, with binoculars. But then he read an article in 1953 discussing Mars’s upcoming opposition in the summer of 1954 and decided to upgrade his instrumentation. His father borrowed a book on astronomy from the library, the last three pages of which had instructions on how to build your own telescope and from where to order the kit. So Rick set about — at eight years old! — building his own telescope and grinding the lenses using only those three pages (eventually his father had to buy the book since the library wouldn’t allow them to borrow it any further). Rick persisted, and the telescope was ready for Mars’s opposition, but disappointingly he didn’t see any canals (nor did anyone else).

Shortly thereafter, Rick stuck a 35-mm camera up to the eyepiece of his telescope, and the astrophotography bug bit him. Jack Dunn (also of the Prairie Astronomy Club) remembers that Rick designed his own chemical developer for processing his images. “It was cheap to make and far more effective than commercial ones. But Rick quickly adapted to computerization of astronomy,” Jack writes in an email.

Rick built his observatory by a lake at the southern end of Paul Bunyan State Forest in Minnesota after he retired.
Rick Johnson

When Rick retired, he and his wife moved to Minnesota where they built a dream retirement home on a lake at the southern end of the Paul Bunyan State Forest, miles away from villages and other sources of light pollution. From the very start, he had plans to build an observatory on the grounds of his new home where he could pursue astrophotography.

Which he did. Rick’s observatory houses a 14-inch LX200R and plenty of equipment for photography. From the very beginning, Rick photographed objects and methodically cataloged them. He’s especially interested in objects that are less familiar. Jack Dunn continues, “One of the hallmarks of Rick’s photography is that it doesn’t just cover the standard astrophotography objects you are used to seeing. Sure they are there [in the catalog]. But there are a huge number of deep-sky objects that have really interesting stories.”

Ron Veys presented Rick with a lifetime achievement award in 2006.
The Prairie Astronomy Club

Rick has always made his work freely available to those on his mailing list which includes schools, fellow amateurs, and even professionals. And now Rick’s catalog of more than 1,600 deep-sky images is available online. He has been continuously updating his catalog throughout the years, and Mark Dahmke (another Prairie Astronomy Club member) has been instrumental in assembling the database and making it accessible online.

Deep-Sky Stories

The “stories” Jack refers to are the reams of information on each source that Rick has included in his catalog. Not only are all the images of the sources in the database, but every image is accompanied by copious notes. These notes include physical data on the source, the history of early observations, and, most pleasingly, Rick’s own experiences in observing them. Many images also have useful annotations, as Mark Dahmke notes, “There are whole fields of galaxies — all labeled for identification in what must have been a painstaking process.”

Among the images you will find in the database are 24th-magnitude gravitational arcs, the remains of the collision of two asteroids, and a previously unknown planetary nebula for which Rick has been credited with the discovery image. Rick also took the image that helped prove that the jet in Arp 192 didn’t actually exist!

Why don’t you see for yourself all the hard work that Rick has done, and do as I have . . . click on random image names and lose yourself in the wonderful world of galaxies and nebulae and comets and asteroids. I’m sure Rick’s work will undoubtedly prove invaluable to generations to come.


Our Work

As our tools for observation grow more sophisticated, scientists at Center for Astrophysics | Harvard & Smithsonian will continue to be at the forefront of dark matter and dark energy research.

NASA’s Chandra X-ray Observatory and optical telescopes help map the distribution of dark matter in colliding galaxy clusters, like the Bullet Cluster. X-ray observations show a heated shock front where the gas from the clusters collided and slowed down, but gravitational lensing measurements show that dark matter was unaffected by the collision and separate from the normal matter.

It is theorized that when some dark matter particles collide, they annihilate and disappear in a flash of high-energy radiation. The Very Energetic Radiation Imaging Telescope Array System (VERITAS) in Arizona, which can detect gamma-ray radiation, is looking for the signature of dark matter annihilation.

The South Pole Telescope in Antarctica and Chandra are placing limits on dark energy by looking for its effects on galaxy cluster evolution throughout the history of the Universe. By comparing observations of galaxy clusters with experimental models, researchers are studying how dark energy competed with gravity throughout the history of the Universe.

Scientists at CfA have led the Baryon Oscillation Spectroscopic Survey (BOSS), analyzing millions of galaxies and charting their distribution in the Universe. The distribution has been shown to trace sound waves from the early Universe, like ripples in a pond, where some regions have higher numbers of galaxies, and others have less. Looking at these distributions, we can more accurately measure the distance to galaxies and map the effects of dark energy.

On the horizon, the Dark Energy Spectroscopic Instrument (DESI) will create a 3D map of the Universe, containing millions of galaxies out to 10 billion light years. This map will measure dark energy’s effect on the expansion of the Universe. And the Large Synoptic Survey Telescope (LSST) will observe billions of galaxies and discover unprecedented numbers of supernovae, constraining the properties of dark matter and dark energy.


Watch the video: Ταξίδι στην άκρη του σύμπαντος National Geographic-greek subs full movie (May 2022).