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Slooh's Online Telescope |

What is Slooh?


Patented technology to explore space.  Robotic, mountaintop, online telescopes, live 18+ hours per day.

Curated journey of discovery. Space is a vast wilderness and Slooh is like a national park, with trails and guides. 

Communal exploration of the Universe. Learn from fellow members using the telescopes.


Slooh has a 20-year legacy spanning the most dynamic astronomical events in history. With top education awards, comet recoveries, and extensive media coverage, Slooh continues to pioneer the most innovative and advanced technology for equitable STEM education.

Why Explore Space?



  • Research and discovery

  • Learn scientific reasoning in a context that helps people achieve a greater understanding of themselves

  • Motivate students to ask questions and seek answers that are personally relevant

Light Pollution

  • Get outside the bubble of our cities to rebuild a connection with an important aspect of the environment.

  • Bring the natural world into focus. Search for the sublime in nature.

  • Tune into the ebb and flow of energy in space.


  • Connect people in our common context as Earthlings.

  • A soothing, spiritual opportunity to ponder our place in the cosmos.

  • Build awareness of Earth as an interconnected ecosystem

Origin Stories

  • What else is out there?

  • Mythology fires the imagination.

  • I want to believe. A means of escape.


  • Look away from the mirror to what lies outside the human creation.

  • Right-size our collective ego relative to other species, on Earth and perhaps in the galaxy.

  • Know thyself within the great beyond.

Guest Educators





Bill Nye

The Science Guy

Celebrating the Solstice with Bill Nye

Nathan Myhryvold

Burnie Burns

Writer, Comedian and Director, Co-Founder of Rooster Teeth

Former CTO, Microsoft, Investor, Author

Asteroid Day

Southern Ring of Fire Annular Eclipse

The Citizen Observatory



Since Slooh launched in 2003, with four telescopes at the world-class astronomical site at the Institute of Astrophysics of the Canary Islands, Slooh members have followed a number of astronomical pursuits:

  1. Tracking Near-Earth Asteroids, making astrometric measurements of their positions to submit to the Minor Planet Center (to determine accurate orbits).

  2. Monitoring the morphology of comets including participation in the largest collaborations projects between professional and amateur astronomers.

  3. Supernovae, novae, comet and asteroid discovery programs.

  4. Art astronomy where members collect the raw astronomical FITS data and process their own color images.

Slooh expanded its telescope network in 2009 when it launched its southern hemisphere observatory at the Pontificia Universidad Católica de Chile facility near Santiago. This not only opened up southern hemisphere skies, with its myriad of deep sky objects, but more importantly, allowed those members tracking asteroids and comets, and those pursuing discovery programs, to access regions of the southern skies poorly served with telescopes.

Further expansion of Slooh's observatory network is underway to extend the hours of operations and sky coverage.

Slooh's Near-Earth Asteroid Tracking Program:

With widespread global media coverage, Slooh's decade-long campaign to raise the awareness of the threat from Near-Earth Asteroids is well known.  But why was the campaign started?

On the night of October October 6th, 2008, Slooh Member Tavi Greiner heard about an asteroid that had only been discovered earlier that day.  Astronomers had calculated that it would impact Earth!

Greiner immediately scheduled Slooh's telescopes at the Institute of Astrophysics of the Canary Islands to capture the fast-moving asteroid “2008 TC3” as it approached Earth.  Slooh members watched the live stream in amazement as they identified the primordial space rock whizzing across the skies - and they were among only a handful of people to do so that night.

Two hours later, the 80-tonne, 13ft diameter asteroid entered Earth's atmosphere 23-miles above the Nubian Desert in Sudan where it exploded in a massive fireball.

It felt like science fiction - and it was obvious from discussions in the Slooh community that members were extremely surprised – and shocked - that an asteroid could impact Earth with so little warning.  In the weeks and months that followed, we started to understand that this wasn't a lone instance.  We also established that many known asteroids, discovered at high cost by a few professional observatories, became "lost" because no one was tracking or monitoring them after their initial discovery.

The entire event inspired Slooh members to begin tracking these Potentially Hazardous Asteroids whenever they swung past the planet.  With Slooh’s assistance, a small group of members taught themselves how-to use Slooh’s robotic telescopes to make astrometric measurements (measuring the precise position of the fast-moving asteroids against the fixed background stars). As Slooh began their campaign to raise the awareness of the risk from these rogue space rocks, more and more members were interested in tracking asteroids and comets.  The group developed a fully structured training program to teach other members how-to track and monitor these potentially cataclysmic space rocks.

Since the Slooh NEA Tracking Program was launched, members have submitted nearly 10,000 measurements to the Minor Planet Center, allowing the asteroids’ orbits to be determined with accuracy – making it far less likely that they will be lost. Their observations have also been published in research with the Max Planck Institute.

Alongside the members’ tracking program, Slooh launched a campaign of live broadcasts to raise the awareness of the threat to Earth from NEAs. Live streaming of the NEAs and Potentially Hazardous Asteroids as they made their close approaches to Earth allowed Slooh to reach millions of viewers. Slooh astronomers were joined by guest experts, including astronauts and NASA officials, to explain why the program was so important.  Slooh’s coverage of a series of large asteroids making close approaches to Earth only days after they were discovered brought the attention of the media who syndicated many of Slooh’s live broadcasts.

In June 2014, Slooh was invited to participate in NASA's Grand Asteroid Challenge, and later signed a Space Act Agreement with NASA to extend the reach of Slooh's asteroid-tracking program.

Over ten years later and Slooh members are still dedicated to this valuable pursuit, with a continuous stream of members graduating through the training program.

Slooh Comet Monitoring:

Of all the objects visible through Slooh’s robotic telescopes comets have always been among the most popular. Since 2003 when the telescopes reached “first light”, members have been capturing and monitoring comets as they travel through the inner regions of the solar system.

Spurred on by the success of the NEA tracking group, a number of members interested in monitoring comets formed in 2012 – the “Comet Attributes, Track and Search” (C.A.T.S.) group. With telescope coverage of both the northern and southern hemisphere, Slooh members were able to monitor comets when they fell out-of-reach from northern hemisphere amateur and professional observatories. The ability to monitor comet morphology over such long periods of time proved invaluable – and came to the attention of the professional community.

Later in 2012, a new sungrazing comet, C/2012 S1 (ISON), was discovered. It would potentially be the most spectacular comet for a decade. Professional astronomers knew they didn’t have the wherewithal to monitor Comet ISON as it approached the Sun – so a NASA-backed program called the Comet ISON Observing Campaign (CIOC) was launched that encouraged and facilitated a massive, global and celestial observing campaign. With large telescopes at the world-class observatory site in the Canary Islands, Slooh members would turn out to be among the most prolific observers with vast amounts of high-quality data collected and made available to the professional community. This valuable data was referenced in several scientific papers with members credited by name for their contributions.

Further “Pro-Am” projects were spawned from the CIOC – Slooh members participated in all of them. Many of the project managers of these campaigns are also Slooh members themselves – acknowledging how capable the Slooh telescopes are. The most recent campaign, the “4*P Coma Morphology Campaign”, saw members working with other amateur astronomers and the professional community to track three periodic comets, 41P/Tuttle-Giacobini-Kresak, 45P/Honda-Mrkos-Pajdusakova, and 46P/Wirtanen, as they approached the Sun. Because of the location of Slooh’s observatories, members were able to track each comet over longer periods of time than any other group.

Slooh members also worked with the European Space Agency (ESA) and generated the largest set of ground-based data of comet 67P/Churyumov–Gerasimenko – the comet visited by ESA's Rosetta Mission. This long period of continuous monitoring helped calibrate Earth-bound observations of comets with those from the close-up views seen by the Rosetta spacecraft orbiting 67P.  Members also worked with the Jet Propulsion Laboratory (JPL) to track comets.

Comets continue to be among the most popular objects among the Slooh membership, and 2019 will see a new “Comet Trackers” club form to continue the valuable work of the C.A.T.S. group.

Discoveries Made By Slooh Members:

As well as tracking and monitoring asteroids and comets, several members actively search for them. Discovering either type of object is becoming more-and-more difficult for amateurs as the number of large-scale global sky surveys increases.  However, these professional surveys have their limits – most notably, few of them can survey low to the horizon. These areas make superb hunting grounds for Slooh members – especially as they can also observe southern hemisphere skies where fewer professional surveys are located. 

While we wait for “Comet Slooh” to be discovered, Slooh members have been responsible for capturing a number of “recovery” observations – being the first to capture a returning periodic comet.  Long-time comet monitoring member Bernd Lütkenhöner was the first to capture the return of the periodic comet 104P/Kowal on January 3rd 2016. His achievement being marked with the publication of Minor Planet Electronic Circular "MPEC 2016-B13: Comet 104P/Kowal". Bernd commented: "Besides this recovery, I have about 160 confirmations of comets and NEOs, but I stopped keeping a list with these confirmations, but do archive copies of the MPECs."

Comets and asteroids are not the only objects tenacious Slooh members hunt. A number search for novae and supernovae – huge stellar explosions. Members have also contributed to professional studies of the cataclysmic events – at a crucial stage. It is extremely important to capture supernova in their early stages, and because Slooh members have immediate access to telescopes, they are also able to make the first “confirmation” observations. They then continue to monitor the progression of the supernova’s brightness that helps determine and understand the physical processes at play.

Slooh was cited in a paper about the supernova discovery SN 2007rt alongside JPL and the Max Planck Institute.

Slooh Observers and Astro Artists:

Members don’t just pursue scientific projects with Slooh’s robotic telescopes. Many take advantage of Slooh’s patented real-time color processing to build image collections of every type of celestial object in the night sky (as well as the Sun using Slooh’s specialist H-Alpha solar telescopes).

These members are like so many amateur astronomers who derive pleasure from exploring the wonders of the night-sky – but without the high cost of purchasing equipment, the steep learning curve required to use the equipment well, and without the poor weather and light pollution that affects so many locations.

Some members concentrate on specific object types, others on monitoring changing planetary features across an apparition, and the most tenacious enter long-term projects to capture all the objects in certain astronomical catalogs, such as the Messier and NGC catalogs – the latter containing 7,840 objects!

Members share their best images using the Observations feature where they can add their perspective on the image and what makes the moment special or add inciteful comments or information. The best of these observations appear throughout the site as “Featured Observations”.

Many members process their own astro art images. These members are among the most active in the Slooh community, sharing techniques and results from their efforts. They collect the raw FITS data generated by the sophisticated and highly sensitive CCD cameras attached to each of Slooh’s telescopes. They combine several sets of FITS data to increase the signal-to-noise ratio, increasing image quality and the detail visible. They also apply their own personal aesthetic preference to the processing that makes each and every resulting image unique to and personal to them.

Member Peter Ilas used the Canary Two Wide-Field telescope to win 2nd place in an astrophotography contest run by the largest European astronomy magazine Kozmos in 2015 for his enormous mosaic image, showcasing the Lagoon and Trifid nebulae in Sagitarrius. The following year saw Peter's glorious image of Mechain's Galaxy (M106) placed 9th out of 4500 entries in the "Robotic Scope" category of the most prestigious annual astrophotography content, the Insight Astronomy Photographer of the Year.

The Saturn Above It


The Saturn Above It gathers together twenty-one short stories about space: a diverse collection of authoritative literary voices on encounters with our universe. This anthology offers a glimpse into our attempts to understand space and our place in it through the varied styles and perspectives of literary visionaries including Don DeLillo, Primo Levi, Steven Millhauser, Kurt Vonnegut, Virginia Woolf, J.G. Ballard, and Ray Bradbury. These stories explore the uniquely human ways we react to the strangeness and enormity of the universe. Together, they offer a portrait of the human psyche and who we are - or could be - when we contemplate all that lies beyond Earth's atmosphere. Edited by Karen Stevens. Buy it on Amazon.



Sophomore year of college I lived at the end of a third-floor dormitory hallway two doors down from my friend Blake Wallens. We had both grown up in Los Angeles but met the first week at Cornell, gravitating to the same fraternity with many of our dorm friends. Delta Chi was situated on Fall Creek Gorge near Carl Sagan’s house. We walked by his house from time to time and wondered about him, a celebrity scientist out of reach to a couple of undeclared undergraduates not yet firing on all our intellectual cylinders. Eventually, I got around to reading several of his books and adopted his unique brand of spirituality – one firmly rooted in our empirical knowledge of man’s place in the cosmos. Sagan made the universe relatable to me; he was a master of articulating the implications of space science and touching people in the process.

After graduation, I moved to New York City and lived on 85th and Broadway in a four-story walk-up with Blake and his best friend from home, John Waller. From our apartment, John and I created one of the first internet advertising networks, 247 Real Media, Inc, which went public in 1998. That summer I married my Cornell sweetheart and in 1999 we had our first child, herself now a student at Cornell. Then we woke up one morning to jets being flown into the World Trade Center and watched helplessly as Blake died along with his good friend Greg Richards and everyone else who showed up for work that day at Cantor Fitzgerald.

I struggled to make meaning of the tragedy all around us and looked for a way to honor Blake and the rest of the fallen. I wanted to confront the corrupt worldview that led to his death, but without bombs and bullets. My thoughts kept returning to Sagan: what if everyone had a sounder understanding of our place in the cosmos? Maybe people could be inspired to rethink their spirituality as I had. Perhaps by looking outward into space, people would find reasons to unite as a species. The internet was the perfect medium to get people around the world communicating about our common condition under a shared sky.

15 years later we have installed ten telescopes in the Canary Islands and Chile and formed a global community of people looking into space together using our patented technology and sharing ideas about what they see. Coming full circle from the tragedy that launched Slooh, we are set to break ground on five new telescopes in the Middle East, giving us almost 24-hour coverage of the night sky. With our partners in the United Arab Emirates, we will translate Slooh into Arabic, the first foreign language version of our website. With a mission of peace and enlightenment, we are continuing a conversation begun back in Ithaca when we wondered about the man who lived on the side of the cliff.

After the idea was conceived in the aftermath of 9/11, it then took two years to secure a location and install our first observatory at the Institute of Astrophysics of the Canary Islands after an aborted installation in Hawaii. We learned the hard way that not every high altitude location is suitable for astronomy and so the dome and telescopes had to be shipped via freighter through the Panama Canal from one remote island in the Pacific to another remote island in the Atlantic. We launched on Christmas Day 2003 to symbolically align ourselves with the winter solstice. If Christians could co-opt an ancient celebration marking the start of winter and graft their mythology on to it, so too would we mark the holiday by reminding people of the original meaning of the occasion; the day the Sun shines the least on the Northern Hemisphere is a time people gathered to ward off that darkness and embrace the daily arrival of more sunlight until the start of summer. We have since expanded this perspective of the solstice to embrace other rituals inspired by an empirical understanding of the Universe and our proper place in it.

It was immediately clear that Slooh couldn’t be built in the New York City technology ecosystem within which I had been operating for nearly a decade. I knew it would be difficult to attract investment interest from venture capitalists, particularly after Lou Dobb’s had just burned through $100 million and gone supernova during the 2001 internet stock crash. There was also the question of how to attract talent given New York’s high cost of living. It was impossible to compete for engineers with well-funded startups and huge corporations such as Google and Facebook. These behemoths have ended up controlling much of what gets put before the public - the result of these funding ecosystems is a devolution into groupthink, as noted by others about Silicon Valley, stifling creativity in the very hotbeds that are supposed to promote innovation and originality. As a result, there seemed little room in New York for the type of non-commercial tech venture I was envisioning. My family and I departed Gotham to build Slooh outside the tech centers. In doing so, we followed the lead of America’s first counterculture, the Transcendentalists, and headed for the hills and woods of New England.

“Why should not we also enjoy an original relation to the universe?” Ralph Waldo Emerson asked in Nature. “Why should we grope among the dry bones of the past…. The sun shines to-day also.” Emerson’s evergreen call to each generation to question the wisdom of its elders resonated with me and led us to an old farm on a dirt road in rural Connecticut. Our farm lies 90 miles north of New York on a patch of land straddling two small towns in Litchfield County, one of the few places still without cell service. The house was built in 1790 along the original trail down from Mt Tom. By 1836 when Emerson published Nature across the state border in Massachusetts, dairy farmers were using this roadway to haul their milk supply to the train station across the Bantam River to be transported to population centers to the south.

Emerson’s challenge to rethink acquired wisdom and his fellow Transcendentalists’ pursuit of collective social action was the philosophical launch pad for Slooh. What if Slooh, in the tradition of the Transcendentalists, could harness this new technology to build a global gathering place that would reject thoughtless conformity, emphasize the essential interconnectedness of humans with our planet and universe, and promote scientific literacy, all while eliminating unnecessary gatekeepers? We would leave behind the Transcendentalist emphasis on inspiration over explanation and its’ somewhat ecstatic embrace of all-pervading divinity, rejecting a relativist position to the truth. We would embrace empiricism and the extraordinary scientific legacy it has enabled while welcoming wonder and lively personal expressions of understanding. Channeling the best in American culture - democracy and a warm embrace of all cultures into one glorious melting pot – while leaving behind an obsession with money, celebrity, and magical thinking. Slooh would be based on the most wondrous of human accomplishments: the continually expanding comprehension of how our universe works and the many creative ways to understand it. We would challenge ourselves to stay open to new ways of understanding the universe, but be rigorous about defending scientific fact. “Keeping an open mind is a virtue,” Carl Sagan wrote in 1996 in The Demon-Haunted World. “But... not so open that your brains fall out. Of course, we must be willing to change our minds when warranted by new evidence. But the evidence must be strong. Not all claims to knowledge have equal merit.”

This still-new tool – the internet – could be the one to return the night sky and the wider universe to all of humanity. It has been almost 100 years since astronomer Edwin Hubble changed our understanding of the universe, showing that many of those twinkling lights in the night sky weren't just a scattering of individual stars but actually galaxies like our own Milky Way, swarming with stars and stretching billions of light years across an expanding universe. Yet, even as Earth teems with nearly eight billion humans and we have organized ourselves into enormous cities, we have crowded out direct human contact with the natural world for much of the population. We've successfully sped up commerce and communication so that many of us are healthier and wealthier than ever before, but we've also altered our perspective in ways I don’t believe we fully appreciate. Consider how the light from our glorious cities radiates more wattage than distant starlight, making it impossible to see the stars.  Walt Whitman’s exhortation to look “up in perfect silence at the stars” is simply no longer possible for many. With another connection to the environment lost, so too fades a basic understanding of man’s place in the order of things. Instead, we exist within a self-reflecting bubble that is as insulated from genuine spirituality as it is from the elements (lending sad truth to The Onion’s 2014 headline “Astronomers Discover Planet Identical to Earth with Orbital Space Mirror”). In fact, people on Earth today have less connection to the ebb and flow of the night sky than the average Mayan thousands of years ago, truly astounding when you consider how much more is known about it. Or as Maimonides put it in the 12th c. C.E. “It is of great advantage that man should know his station, and not imagine that the whole universe exists only for him.”

The narcissism that has separated us from the rest of our universe has also had implications for the environment. Within the narrow scope of our immediate surroundings, we can convince ourselves that we are lords of the dominion, and have helped ourselves to the entitlements that come with it. Paradoxically, this intensely self-focused perspective has weakened our species, not strengthened it, and it has become increasingly difficult to maintain this posture given what man-made climate change is bringing us. “In an age when man has forgotten his origins and is blind even to his most essential needs for survival, water along with other resources has become the victim of his indifference,” Rachel Carson wrote over 50 years ago in Silent Spring. “Here again we are reminded that in nature, nothing exists alone.” Consideration of “lesser species” and the healthy ecosystems they need to thrive are seen only in the context of their relationship to us, rather than the nuanced and intertwined relationship we share with all life on the planet. As we have learned more about the complicated web that sustains life, it has become undeniable that each man-made change to our planet has unpredictable and often far-reaching consequences. Human achievement would be better measured by mastery over our own natures, not the planet. Positioning the servicing of our prosperity as primal acts of survival is a fiction that no longer convinces. And even as we arrive at the point of jeopardizing our own well-being, we lack the sustained discipline and clear-sighted wisdom to address it. The zero-sum game of our political system courses on and sets the agenda of priorities.

Given the discovery of the first exoplanet in 1992 and the realization since that 30 percent of stars in the Milky Way have planets in orbit around them, wouldn’t it better serve us to cultivate a sense that we are ordained by our astounding evolution from monkey to man to be not masters, but stewards of a planet -- just one among many in the galaxy? If there are people who don’t believe there is life elsewhere in the universe, I have yet to meet one in the Slooh community. Perhaps if this became a part of our collective consciousness, we’d question whether we have a right to flourish at the expense of other living beings on Earth, or if it is even possible given what we know about the complicated interdependencies of life. This understanding could help us arrive at a greater purpose for our lives than mere dominance and consumption.

We now have the situational awareness, tools of communication, and understanding of one another to strive collectively toward unification at a planetary scale. Wouldn’t this be a worthy aspiration for us, the first time in human history all people organized together around a singular purpose? Maybe that grand vision starts with a simple unifying view of space from telescopes on Earth. It’s not such a utopian idea; the modern environmental movement – waking us up to the existential need to change our ways - is often dated to a photograph taken from space. "Earthrise", a deeply moving 1968 photo of earth taken by Apollo 8 astronaut Bill Anders from lunar orbit, provided us with a fresh perspective of ourselves, revealing Earth to be a fragile beauty. “Earthrise” inspired poet Archibald MacLeish to write:

The medieval notion of the earth put man at the center of everything. The nuclear notion of the earth put him nowhere -- beyond the range of reason even -- lost in absurdity and war. This latest notion may have other consequences. Formed as it was in the minds of heroic voyagers who were also men, it may remake our image of mankind. No longer that preposterous figure at the center, no longer that degraded and degrading victim off at the margins of reality and blind with blood, man may at last become himself. To see the earth as it truly is, small and blue and beautiful in that eternal silence where it floats, is to see ourselves as riders on the earth together, brothers on that bright loveliness in the eternal cold -- brothers who know now they are truly brothers.

The world needs a refresher course in astronomy and the philosophical perspectives that come with it. We have discovered much about the universe and it is time that we address the spiritual implications. A view through a telescope reminds each of us to imagine worlds beyond ourselves and within our power to explore. Across nations and generations, we have developed an extraordinary foundation of knowledge that can propel us out into space. May it also ignite our unified mission as a species.



Slooh is dedicated this day December 25th, 2003, to Blake Wallens and all those who were killed in the attack of September 11th, 2001