NTT, 1991 - the original NTT, 1998 - post Big-Bang NTT, 2002 - migrated to the RITZ NTT, 2011 - at the NOB

Olivier Hainaut


Nice Results

  • The first interstellar asteroid, 1I/2017U1 `Oumuamua passed in front our telescopes: it is a weird, elongated reddish object. More at ESO, IfA, Gemini, CFHT, NASA, and our results are published in Nature. Karen Meech gave a TED Talk on our discovery, and I contributed an ESO Blog post. We also studied its complex rotation. Finally, studying its motion, we noticed a weird deviation from its orbit: it is being pushed by something, most likely cometary activity. After all, `Oumuamua is a comet! More at ESO, NASA/HST, IfA, CFHT (with a cool animation), ESA. This new result was also published in Nature, and I give more behind-the-scene details in a Nature Blog post.

  • Trying to save the planet... With Andy Williams, I explain how in this ESO Blog on threatening Near Earth Asteroids.

  • Weird tail-less comets, the Manxes, are coming from the Oort Cloud in the outer solar system. This project is lead by Karen Meech, and the observations were done with Gemini. We observed one of these Manxes in more details, and it turned out it is a rocky remnant from the formation of the terrestrial planets - the result was published in Sci.Adv; more at ESO, IfA, and CFHT - a nice summary in Gizmodo thanks to Maddie Stone.

  • Halley's Comet is still observed! in March 2003, at the distance of Neptune. This was also the "Astronomy Picture of the Day" on Oct.3. I had also observed that comet in 1994, as it passed the halfway mark (January 1994): observation of the faintest solar system object ever observed. [at that time]. In 1991, I detected a majour outburst on the comet - which should have been quiet at that time. This outburst created some waves in the public. For instance, a lady contacted me to ensure me that this was a direct cause (or was it a consequence?) of the Gulf war. Also, a journalist concluded that the comet had completely exploded (which in turned caused some additional comments-in french in this example).

  • Comet Hale-Bopp was still very active in 2001, esp. considering the distance at which it was. We observed it at the 2.2m at ESO in Mar.2001; here is a nice color image (and is also available in Italian, in Hebrew elsewhere...). It was also an "Astronomy Picture of the Day".

  • The object 2000 OF8 was discovered as an asteroid. We found out that it is really a comet

    The Trans-Neptunian Object 1996 TO66 has been extensively observed; we obtained many interesting resulst on that object, including its rotation period. This is described in an ESO Press Release, and in more details in one of my papers.

  • A strange supernova, sn 1998 bw, which seems to be related to a Gamma Ray Burst (May 98). An ESO Press Release has been published on that object. This object turned out to be the key that unlocked the mystery of GRBs

  • Volcanoes on Io, using the UH adaptive optics instrument on the CFHT.

  • Observations of Comet Hale-Bopp. The IfA Hale-Bopp page contains plenty of info and links about that comet; for nice pictures, check out the Images and Spectra page.

  • Rapid Changes in the Inner Coma of Comet Hyakutake (March 1996): acrobatic observations of this nice comet with a great telescope and a great seeing!

  • The discovery of a Transneptunian Object: 1994 TG2 (October 1994): one more TNO (only about 60 were known at that time), but I discovered this one :-)

  • High Resolution HST Images of Pluto and Charon (May 1994): the first detailed, direct look at Pluto and Charon's surface, long before New Horizons.

Past and On-going Projects

  • With the launch of Starlink's satellites, astronomers across the world started to wonder if, in a few years, there would be more bright satellites in the sky than stars. I contribute to study and model the visibility and effect of these satellites. Preliminary results were published. See my satellite page for a primer, simulations, plots... and for custom-plots of satellite impacts for your place.

  • Trans-Neptunian Objects: The MBOSS color database, a compilation and analysis of published MBOSS photometry

  • 67P+Rosetta: ground-based observations of comet 67P/Churyumov-Gerasimenko during the Rosetta mission.
  • Castalia: a space mission to Main-Belt Comet 133P/Elst-Pizarro.
  • Recovery and follow-up of potentially threatening Near-Earth Asteroids
  • ESO's Cosmic Gems is a neat project to make good-looking astronomical images.


Google Scholar - ADS custom query.

Software tools

  • Satellite constellation simulators: two webtool to evaluate the impact of satellite constellations (Starlink, OneWeb...) on astronomical observations.
  • Astrolabe Generator, a web-tool to produce "astrolabes" for your site (updated version at - The one at IfA is outdated - new version 2020!) An on-line preview of the cardboard version is available for Paranal.
  • MeteoMonitor, a web-tool to monitor the conditions at ESO/La Silla. It also exists for ESO/Garching, at MeteoMonitor - Garching.
  • POS1/Astromet: an ESO/MIDAS package for astrometric calibration of scientific image (plates and CCD); it can get its GAIA standard stars automatically through the net.
  • TMAG: an ESO/MIDAS package for photometric calibration of CCD images, with quasi-automatic identification of Landolt's stars, and interactive edition of bad points.
  • All-sky camera: I was involved with getting an all-sky camera on La Silla - the original one is still up and running after ...almost 20yr? LASC was state of the art at that time... Then on Paranal, a custom-developed camera was installed: ApiCam-3. Here is a link to the archives - go to the ESO webcam page for real-time access (and kudos to Apical for their great hardware and service).


Personal stuff

You can also
  • Enjoy my (small but growing) UFO picture collection.
  • Have a look at my curriculum vitae
  • get my addresses
  • On this page, you will find the whole, email exchange constituting the Car 42 Saga. This is part of the ESO folklore, probably of no interest for outsiders...

Marie-Claire, my wife, has her page at MCHR - Marie-Claire Art Research project. This other page at the Canada-France-Hawaii Telescope is a pretty good summary of her previous work, with plenty of palmtrees and aloha. Note that she left CFHT for Gemini, where she worked until 2009. There was a nice article about her in the July 98 "Ciel & Espace" (sorry, no English version).

Note that this is a private page. "Any view or statement made is not part of an official standpoint of ESO."

Olivier R. Hainaut (ohainaut at