≡ Menu

Amateur Astronomers Join Hunt for Exoplanets

An Australian amateur astronomer named Thiam-Guan Tan has made a name for himself in the realm of exoplanets. Tan participated in the discovery of an exoplanet that may orbit within its star’s habitable zone. LHS 1140 b is a super-Earth some 41 light years from Earth that orbits a red dwarf star. Back in September of 2016, with a number of professional observatories looking at the host star, Tan provided key data to help verify the existence of LHS 1140b.

“It was fortunate that I was able to catch a transit,” said Tan, a retired engineer with a 12-inch telescope who has also discovered several supernovae. He is quoted in a newspaper called The West Australian as saying “That night, the Centre for Astrophysics had lined up five other telescopes across Australia and Hawaii to observe but they were all clouded out.” Tan’s work with exoplanet transits continues, an illustration of the role that talented amateurs with affordable equipment (Tan’s telescope cost $15,000) can play.

Image: Thiam-Guan Tan with his telescope. Tan notes that “A couple of sources of encouragement were The Discovery of Extrasolar Planets by Backyard Astronomers (Castellano & Laughlin, 2002) and Bruce Gary’s book Exoplanet Observing for Amateurs. Credit: Thiam-Guan Tan.

In the same vein, I’ve been looking at a project called the Habitable Exoplanet Hunting Project, emerging under the guidance of coordinator Alberto Caballero, himself a dedicated amateur astronomer in Spain who is visible on YouTube through his efforts on The Exoplanets Channel. The idea of the new project is to help amateurs discover more exoplanets in the habitable zone, restricting the search to G-, K-, and M-class stars that show low flare activity. The stars examined by the project are all known to have transiting exoplanets outside the habitable zone, and all are within 100 light years of the Sun.

How to find out whether there are as yet undetected planets around such stars? Caballero looked at the amateur astronomers involved in TRESCA (Transiting ExoplanetS and CAndidates), a group organized by the Variable Star and Exoplanet Section of the Czech Astronomical Society comprising 191 observatories. He also consulted the American Association of Variable Star Observers (AAVSO) in his quest to find amateurs willing to participate in a global venture, one that could monitor specific stars at a predetermined time each week. Needless to say, the more volunteer astronomers, the better.

Image: The Parco Astronomico Lilio Savelli, Italy, an amateur observatory participating in the Habitable Exoplanet Hunting Project. Credit: Alberto Caballero.

By gathering data 24 hours a day, seven days a week, the team hopes to monitor individual targets when a transit of a habitable zone planet could occur. 32 participating amateur observatories are already onboard as the project comes online, and Caballero notes that southern sky coverage would be particularly welcome as the effort builds. You can see photos of the participating sites, some of which are quite impressive, here.

There is no shortage of targets. Among M-dwarfs, the most numerous nearby stars, there are almost 2,000 within 100 light years, and Caballero says that amateur equipment is capable of detecting habitable zone planets like the super-Earth around LHS 1140b, with a transit depth of 0.6%, as well as smaller worlds.

Caballero likewise counts 508 G-class stars within the same 100 light year radius, and well over 900 non-flare K-class stars as well. He believes that as many as 25 habitable zone planets may be discovered using these methods, if a large enough telescope network can be implemented. The chart below, showing 10 non-flare G-, K-, and M-class stars within 100 light years with known transiting exoplanets (as of March, 2019) is drawn from the project’s website.

The Habitable Exoplanet Hunting Project assumes that each amateur astronomer would need to gather data from the target star about one hour per week, provided an early goal in the range of 200 observatories can be reached. From the project’s website:

To make the process easy, the observations would be conducted at the same local time of the astronomers. For those cases when there is no observatory in a specific time zone, the observations would be assigned to the closest observatory. Adjustments would also have to be made on real time to exchange observation days when skies are cloudy. In addition, considering that most of the observatories are located in the Northern hemisphere, the Southern hemisphere observatories would have to undertake more hours of observation; for that, it would be ideal the use of robotic telescopes. Getting help from Southern AAVSO observatories could also solve the problem.

M-dwarfs would seem to be prime target stars for an effort like this because habitable zone planets are going to be close enough to the host to have short orbital periods, with high transit depth, but Caballero told Jamie Carter in this article in Forbes that his team favors K-class stars, which emit lower UV and X-ray radiation than the average G star (like the Sun), and also have a longer lifetime. It’s a telling reminder that an Earth ‘twin’ may actually orbit a slightly different kind of star, where conditions for habitability could be better than here.

Caballero’s short video explains what the project hopes to accomplish, and he tells me the network will begin a campaign on GJ 3470 some time in January. Here we have a known mini-Neptune of about 14 Earth masses with a radius 4.3 times that of Earth, orbiting a star in the constellation Cancer. So far it’s the only planet known around this M-dwarf, in a tight orbit whose proximity to the host, in addition to its size, precludes habitability (in fact, its atmosphere seems to be evaporating). GJ 3470 thus offers an ideal chance for the Habitable Exoplanet Hunting Project to show what it can do even as it enjoins amateurs to bulk up its network.


Comments on this entry are closed.

  • Andrew LePage December 10, 2019, 10:30

    When I was researching the backstory of the detection of LHS 1140b a couple of years back, I was thrilled to see the key role Australian amateur astronomer Thiam-Guan Tan played (I’ve always been an advocate for amateur astronomers doing real science). Details on the discovery of LHS 1140b (as well as its potential as a habitable planet) can be found here:


    • Harry R Ray December 20, 2019, 11:39

      Andrew Le Page: Speaking of potentially habitable exoplanets. Jeff Caughlin tweeted this 14 hours ago “This was a huge effort to manually vet thousands of #KeplerMission KOI’s by the False Positives Working Group over several years. Some planets were rescued, some destroyed…” Can you find out the fate of these three KOI’s mentioned on your website in the past: KOI 7923.o1, KOI 8012.01, and KOI 8174.01 and post the results HERE as a reply to this comment? It would be very much appreciated. This appears to be the final. Final, FINAL attempt to vet KOI’s by Kepler scientists. This may not be the last attempt overall(i.e. outside groups may try as well) for KOI’s, and this, or other groups may try to manually vet KIC’s that never made it to KOI status.

  • Alberto December 10, 2019, 11:03

    Excellent article, thanks a lot!

  • Alex Tolley December 10, 2019, 14:16

    Is there a website that explains the details of how the amateurs take their measurements (and with what kit) and how the many small data sets are combined?

  • Another David December 11, 2019, 0:31

    Oops, sorry I see that Bruce Gary’s book was already mentioned. Also the link to the Habitable Exoplanet Hunting Project leads to a website which my browser says has malware. Is there a typo in the link ?

    • Paul Gilster December 11, 2019, 7:46

      The link should be correct, but let me check with Alberto about the malware issue. I haven’t run into that warning.

  • Michael C Fidler December 11, 2019, 11:05

    I had a great idea, what if exoplanets civilizations wanted to send out signals during transits! The transit creates a natural power source and receives its power from the same idea as the Earth’s Terrascope.

    Well, after coming up with this great idea I noticed that the “LcTools: A Windows-Based Software System for Finding and Recording Signals in Lightcurves from NASA Space Missions.”
    that David M. Kipping of Terrascope fame was involved with in its development. Of course I checked to see what papers he had written about scopes and Lo and Behold I found this:
    A Cloaking Device for Transiting Planets.
    David M. Kipping, Alex Teachey
    (Submitted on 29 Mar 2016)
    “The transit method is presently the most successful planet discovery and characterization tool at our disposal. Other advanced civilizations would surely be aware of this technique and appreciate that their home planet’s existence and habitability is essentially broadcast to all stars lying along their ecliptic plane. We suggest that advanced civilizations could cloak their presence, or deliberately broadcast it, through controlled laser emission. Such emission could distort the apparent shape of their transit light curves with relatively little energy, due to the collimated beam and relatively infrequent nature of transits. We estimate that humanity could cloak the Earth from Kepler-like broadband surveys using an optical monochromatic laser array emitting a peak power of about 30 MW for roughly 10 hours per year. A chromatic cloak, effective at all wavelengths, is more challenging requiring a large array of tunable lasers with a total power of approximately 250 MW. Alternatively, a civilization could cloak only the atmospheric signatures associated with biological activity on their world, such as oxygen, which is achievable with a peak laser power of just around 160 kW per transit. Finally, we suggest that the time of transit for optical SETI is analogous to the water-hole in radio SETI, providing a clear window in which observers may expect to communicate. Accordingly, we propose that a civilization may deliberately broadcast their technological capabilities by distorting their transit to an artificial shape, which serves as both a SETI beacon and a medium for data transmission. Such signatures could be readily searched in the archival data of transit surveys.”

    So in exoplanets surveys should we be looking for possible signal that may temporarily make the exoplanet disappear, or even change frequencies? The scope at the focal point of the ET civilization atmospheric lens could produce a variety of signals and spectral signatures without the use of lasers. It would be using the combined power of the sun in their system and the lensing from the planets atmosphere to send out the signal. The question is how this may be recorded if the peak is of very short duration?


    Planetary Lensing: Enter the ‘Terrascope’

    Actually, I was hesitant to write about this because it sounded like a crazy idea, but Kipping had already seen the potential and it may be something that amatuer astronomers can pick up in their exoplanet photometry!

    • Mike Serfas December 12, 2019, 7:25

      I would be hesitant to suggest hiding the position and habitability of the Earth by replacing its natural signature with a laser at a specific location. What if the aliens were to launch a small cable far from their telescope, and observed that as it spins it blocks an entire planet’s worth of light emitted from a very small location? Maybe that’s their SETI method.

      Also, if the aliens are determined to broadcast their location widely to savages, couldn’t they just launch a mirror to a point readily separated from their star, and bounce their messages from that? (They could still time it to match their transits if they wanted to) A flat, well controlled, rotating mirror might serve as one part laser-launched light sail probe, one part communications system scanning and targeting all the stars angularly near to its destination.

    • Michael C Fidler December 13, 2019, 20:04

      Short-lived light sources discovered in the sky!
      Vanishing & Appearing Sources during a Century of Observations” (VASCO)
      “A project lead by an international team of researchers use publicly available data with images of the sky dating as far back as the 1950s to try to detect and analyse objects that have disappeared over time. In the project “Vanishing & Appearing Sources during a Century of Observations” (VASCO), they have particularly looked for objects that may have existed in old military sky catalogues from the 1950s, not to be found again in modern sky surveys. Among the physical indicators that they are looking for are stars that have vanished in the Milky Way.”

      “When a star dies it either undergoes very slow changes and becomes a white dwarf or it dies with a sudden bright explosion i.e. supernova. A vanishing star can be an example of an “impossible phenomenon” that could be attributed either to new astrophysical phenomena or to extra-terrestrial activity. Indeed, the only non-ETI (extra-terrestrial intelligence) explanation for a vanishing star would be exceedingly rare events called “failed supernovae.” A failed supernovae is theoretically predicted to occur when a very massive star collapses into a black hole without any visible explosion. Other physical indicators of ETI activity that the authors are looking for are signs of red interstellar communication lasers and Dyson spheres. A Dyson sphere is a hypothetical giant structure surrounding a star to harness its energy.”


      The Vanishing & Appearing Sources during a Century of Observations project: I. USNO objects missing in modern sky surveys and follow-up observations of a “missing star”



      “Any sufficiently advanced technology is indistinguishable from magic.” – Arthur C. Clarke’s Third Law.

      “The Vanishing & Appearing Sources during a Century of Observations (VASCO) project aims at finding astro-physically interesting mismatches between historical sky surveys: ‘Which object flickered out from our celestial radar?’, ‘Which locations hint at astronomical spectacles to discover?’.

      Answers to these questions could lead to interesting scientific findings, like new astrophysical phenomena or to — who knows — interesting targets for follow-up SETI observations. The sheer scale of current existing sky surveys prompts us to develop new computational tools, with a glamorous role given to machine learning and artificial intelligence. The project gives a forum for interaction between professional scientists with various background, serious amateurs and curious citizen scientists.”


      Now this is cool, these objects can be monitored by amateurs astronomers thru photometry or even long exposure imaging for any current activity. Who knows you might just find the Holy Grail!

      I noticed some of you have been complaining about cost to get involved in doing such things but $15,000.00 is like buying a Ferrari. There is a very large market for high quality second hand telescopes and their optics, so as in any interest you need to do research. Anyone good at building simple projects can buy a good mirror second hand and make the tube assembly themselves. There are many good mounts available second hand and I would recommend a Losmandy G-11 Equatorial Mount. Check out the Cloudy Nights classifieds:

      As for cameras, they recommend a monochrome, and I found a good buy on AliExpress:
      “6.3MP 51FPS USB3.0 Fan-Cooled mono Astronomy Guiding Camera G3CMOS06300KMA with Sony IMX178 CMOS telescope camera”


      You need a filter wheel and a set of LRGB filters to do color planetary and astrophotography, but are not necessary for photometry.

  • James M Essig December 11, 2019, 14:36

    I’d like to start doing this. I have a modest telescope but have been wanting to get back into using it.

  • Charley December 11, 2019, 15:34

    Afraid I don’t have $15,000 to put into an amateur search of anything (i.e. I don’t have the money to waste), but good luck to all those who are pursuing this-it’s a shot of history that’s for sure

    • ljk December 12, 2019, 13:07

      That is why a club effort, where a group of amateur astronomers could pool their money and resources to share such a facility, might work best.

  • Laintal December 12, 2019, 2:49


    I know a few people here in NZ doing this work, but not in this network, when I have the spare time and funds this is going to be my research project!

  • Robin Datta December 12, 2019, 7:27

    With the methods described here, amateurs can not only collect new data, but also work with existing databases. The prospects include resetting the Fermi paradox and a trip to Stockholm.

    • ljk December 12, 2019, 13:09

      Could an amateur without a Ph.D win a Nobel prize in science? I get the impression that one needs to be a long-standing professor or professional researcher to win this award. And do not tell me Nobels are any less of a popularity contest than any other of these prizes. As usual, it is who you know first.

      • Laintal December 12, 2019, 16:44

        Hi Ljk

        From some the the feedback on social media I don’t think I’ll be in line for a Nobel anytime soon, but have some great contacts like yourself and others :)

      • Robin Datta December 13, 2019, 19:56

        Gertrude B. Elion, Sir Chandrashekhara Venkata Raman, Tu Youyou, Guglielmo Marconi, were sans PhDs.

        And we have the Rumpelstiltskins turning suspected pigeon droppings into something else.

  • Harry R Ray December 14, 2019, 11:04

    I know that this is OT, but I just HAD to post this SOMEWHERE! Centauri Dreams readers, drop that you are currently doing and google https://www.discovermagazine.com/the-sciences/astronomers-just-mapped-a-pulsar's-surface-for-the-first-time IMMEDIATELY and feast your eyes on the most incredible image in the HISTORY of images! Pulsar J0030+0451 has a mass of 1.35+/-0.05 Msun and a radius of 8 miles(13 kilometers. The article focuses on either two or three “hot spots” that move around the south polar region, but what absolutely ASTOUNDS ME are the Titan polar sea-like albedo(ONLY: Elevation is obviously IMPOSSIBLE on neutron stars due to the crushing gravity)features on the pulsar’s north polar region and an “arch”-like feature running from the pulsar’s south pole up to the far eastern side of the equator. The two images show the hot spots in different positions, but the “albedo”(maybe slight differences in x-ray “color”) features lign up EXACTLY THE SAME in BOTH IMAGES!!!!! The two imaged were taken at different times by the Neutron star Interior Composition ExploreR( or NICER for short) on board the International Space Station.

    • Harry R Ray December 14, 2019, 15:45

      Discover Magazine just got one-uped BIG TIME! Google https://astronomy.com/news/2019/12/astronomers-map-a-neutron-star's-surface-for-the-first-time and watch the pulsar make one full rotation, exposing the ENTIRE SURFACE! Eerily similar to the one full rotation of Ceres where the bright spot in Occator Crater just pops out WITHOUT WARNING at the mid-point of the rotational sequence invoking visions of landing lights being turned on at that precise instant. Remember that one? Get ready for a heavy dose of DEJA VUE!

  • Harry R Ray December 14, 2019, 15:07

    OOPS: I tried clicking the blue part of my ABOVE comment and came up with an image of a hairy mamouth(obviously NOT a pulsar)and the following message: 404 ERROR PAGE NOT FOUND.” However, I JUST CLICKED “THE SCIENCES” at the left hand side of the topic options under the “Discover” logo and got the images. Currently there at the top row/second column position, but obviously this will change as new topics are added.

    • Robin Datta December 15, 2019, 3:55

      Hubbout this one…
      Astronomers Just Mapped a Pulsar’s Surface for the First Time?
      Let me know when we receive an decipherable, intelligent signal.

      • Harry R Ray December 16, 2019, 10:36

        WOAH!!!!! Even I(who sees possible ETI messages in EVERY bizarre signal observed by ground or space telescopes – case in point – `Oumuamua’s weird light curves)didn’t think of THAT possibility. Can’t see any OBVIOUS messages in the rotating light curves, so I guess they are just Cheela bases.

  • ljk December 16, 2019, 10:33

    Here are the links. They were working when I posted them:



    I do not see a single Cheela on any of them, however. Very disappointing.

    • Harry R Ray December 17, 2019, 10:51

      ljk: An individual Cheela is about the size of a sesame seed, so we need to move NICER out to ~500 au and do the observations again, and then when we get back, EPSI should be fully operational and we could then spend the rest of our lives looking for them in the enhanced ESPI images (lol).

  • Michael C Fidler December 17, 2019, 10:06

    This is good news for planets around Red dwarfs, a deep water cycle that could last for billions of years is possible on Earth. With long term comet impacts and possibly water worlds around earth size to super earths in close in orbits around red dwarfs any stripping would be replenished even after billions of years of flaring. The Trappist 1 planets may be a good example of this and all of those planets may still have water on their surface. Hopefully the Cheops telescope will be launched in the next few days (it was delayed today) and that should give us a better idea of the density of these planets.

    Would A Deep-Earth Water Cycle Change How We Understand Planetary Evolution?

    The researchers used lab-based mimicry to study the mineral stishovite, which is a high-pressure form of quartz, when it’s with water under high pressure and temperature conditions. We already know substantial amounts of water can be stored in silicate minerals in the Earth’s upper mantle, which exists between 100 and 670 kilometers (or 62 to 416 miles) deep. But the team examined stishovite and water under simulated conditions like those found deep in the lower mantle, which exists between 670 and 2,900 kilometers (or 416 to 1,802 miles) down, where it was thought that much less water could be stably stored in minerals.

    • Michael C Fidler December 17, 2019, 23:14

      I forgot to mention in the last comment that this means that large quantities of water may be found deep in the lower mantle almost halfway to the center of the earth (actual 45%).

      Some new and interesting information on why there are so many Sub-Neptunes. What they are finding is that Hydrogen in the form of highly-pressurized H2 is high enough for the atmosphere to readily dissolve into magma core.

      Why are there so many sub-Neptune exoplanets?

      Superabundance of Exoplanet Sub-Neptunes Explained by Fugacity Crisis.

      • Harry R Ray December 18, 2019, 10:27

        Correct me if I am wrong, but I thought that the smallest planets that CHEOPS will be studying are mini-Neptunes with thick hydrogen atmospheres(case in point – K2 18 b)and that we are going to have to wait for JWST and Ariel to characterise the atmospheres of the TRAPPIST-1 planets.

  • Michael C Fidler December 18, 2019, 18:29

    Yes, you are right and I did some searches and came up with several different answers. The ESA site is saying 10,000 kilometers on up, which is 6,200 miles so it might be possiable but the problem is the brightness of Trappist 1. It’s magnatude is 11 in the infrared which is visible to Cheops but it may be to long an exposure for the primary 3.5 year mission. I have been looking for a list of the stars that they will be studying but have not found one. The press is saying many things but the ESA site is saying several hundred stars and 20% of the time is allotted for guest research. This includes looking for moons and rings around the planet’s. The great news is a successful launch and the possibility of reaching earth size planets!

  • Harry R Ray January 7, 2020, 10:33

    Add TOI 700 to that list! There is an outside chance for an ADDITIONAL habitable zone planet in the outer portion of TOI 700’s Goldilocks region.

    • Harry R Ray January 8, 2020, 11:04

      Here are the specs for the M2V TOI 700 system: b – 1.01 +0.094/-0.087 Earth radii, 9.97701 +0.00021/-0.00028 days orbital period. c – 2.63 +0.24/-0.23 Earth radii, 16.051098 +0.000089/-0.000092 days orbital period. d – 1.22 +0.073/-0.063 Earth radii, 37.462 +0.0007/-0.001 days orbital period. b and c are not in the habitable zone(conservative OR optimistic)and are very close to being in a 3/2 resonance with each other. If either a non-transiting or a very small(Moon to Mercury sized, so that TESS could NOT detect it)transiting planet were to orbit with a period in the 24-25 day range, this ~3/2 near resonance could then continue THROUGH d and out into the OUTER habitable zone at around 53-55 days and even beyond THAT into the cold region outside the habitable zone. It is IMPERATIVE that ESPRESSO be dedicated sufficient time to find out whether this is true.