Interviews

Home - Meet the... Stefan Kürti

Asteroid hunter and interviewer of inspirational astronomers

What is noise for one researcher is data for another researcher.

Jiří Grygdiv>

He wanted to make his living from astronobut he gave up his study prematurely and preferred his hobbies. For many years he followed the world of stars only passively. The emerging internet allowed him to make a great comeback. The desire for discoveries forgotten for decades had returned, patience and perseverance brought him success at the end. He searches for asteroids in the archives of professional observatories and loses the track of the time. In addition, he writes about talented astronomers from around the world and presents their exceptional performances. The discoverer of asteroids and the interviewer of inspirational astronomers, Stefan Kürti.

What do you do for a living? What is your profession?

I am a clerk at the Municipal Office in Nové Zámky. For more than 20 years, I have been providing advice on loans for housing and for the renovation of apartment buildings. I advise to applicants in completing their documents and, after granting the loan, I follow the usage of provided funds.

You are a passionate astronomer, what led you to this hobby?

There were several impulses. My initial interest in astronomy was caused by the human missions to the Moon. The real boost was the flight of Apollo 17. In December 1972, when the last human crew was approaching the Moon, I traveled with my father to Prague for an exhibition. That's where my journey into astronomy beganbr>
As a child, I loved to read – I looked for newsstands offers, always everywhere. This was also the case in Prague. So that was how I came across the Czech astronomy magazine Říše hvězd (Realm of Stars). After returning home, my father subscribed the magazine at my urging him. A few months later, I got to know the Slovak magazine KOZMOS in a similar way and I got another source for reading. In the evenings, I began to watch the waxing and waning Moon. And when it disappeared from the sky totally, a lot of twinkling stars remained there. Gradually, I discovered that the sky offers endless possibilities for observations, and the apparent monotony was diversified from time to time by unexpected guests – meteors, comets, or supernovae. My interest in the universe was also intensified by Comet Kohoutek 1973f. Although I did not observe it, I eagerly read everything written about it.

Human spaceflights and astronomical magazines were soon followed by another strong impetus. What was that?

Yes, another impulse followed in the fall of 1974. At my favourite newsstand, I found an announcement about the knowledge contest, „What we know about the stars?" The first prize was an astronomical telescope, and probably that´s why I was very attracted to it. But there was a problem. The age limit was 15 years and I was a year younger. When my father saw how I longed for it, he went to the organizers and arranged an exception to be made. There, they alsoised him to enroll in an astronomical club at the local grammar school. Coincidlly, two future participants in the competition were also preparing there. Visits to the club were useful; they broadened my „astronomical” horizon. However, as it turned out later, it was not enough to win.

The awaited day came, there were eight of us. My neighbor at the desk, Zsigmond Bödők won that day. He made it to the national final, where he came second. I finished in the middle ranking of the competition field, fifth. I playfully mastered questions from astronautics, but failed in questions from practical astronomy, my knowledge of constellations was weak. However, I was proud of myself, because older and more experienced opponents ended up behind me. The competition showed me that I don't know so much about stars yet and there is still a lot of to find out. And so I kept learning.

Magazine Říše hvězd, souvenir from Prague, which started interest for astronomy.
Magazine Realm of stars, souvenir from Prague

You were fascinated by astronomy, did you think of it as a future profession?

As a child, I wanted to be an archaeologist and I was also attracted to chemistry, but it only lasted until I started learning it at school. I didn't enjoy it at all. Then came the human flights to the Moon, so I wanted to become an astronaut, but talso didn't last long. I wore glasses and it was a disqualification then. If no astronaut, then I would be an astronomer. That kept me going on throughout high school. Finally, I started studying nuclear physics at Comenius University in Bratislava, and at the same time a post-secondary study of astronomy in Hurbanovo as an „insurance”, if it didn't work out at university.

Why did you choose the study of nuclear physics?

They hadn’t opened the astronomy subject that year, so I signed for nuclear physics and I planned to change my subject to astronomy after two years. Learning at high school went easy and without problems for me. Those days I devoted my time to „gather” information about space and astronautics, and moreover, I spent more and more time listening to pop music. Passion for popular music became another one among my hobbies. During my university years, however, it was necessary to significantly devote more time to learning, but I preferred my hobbies instead. When period of exams came, I was struggling with mastering the curriculum. For two years, I had been fighting with myself to find out what should come first. And then hobbies won. I left the university prematurely after two years.

So did end your dream of becoming an astronomer?

It looked like that for a long time. Compulsory military service arrived, which prevented me from completing post-secondary studies. After returning from military service, I got b in Bratislava and my employer allowed me to study economics and mathematical ods in economics. My interest in the universe narrowed only to reading astronomical magazines for many years, and I devoted more time to my other hobby.

Was it a popular music?

Yes. If I wasn't reading, or didn't have my eyes glued to the eyepiece of my telescope, I listened to music. The BBC's World Service had a weekly program focused on pop music news. In addition to listening brand new hits, you could request a song to play for you, but what attracted me the most was the competition. Each week, they released a riddle consisting of excerpts of three songs, and the task was to guess the performers. The winners won vinyl SP or LP records of their own choice. And getting the original records of world-famous bands or singers at that time was a big thing.

Picture of the month July 1991, Astronomy Now, Photo: Š. Kürti
Picture of the month July 1991, Astronomy Now.

I competed and won for years. Initially, I sent answers to the competition by mail, later I preferred to report it by telephone. Once, when I reported the answer, I mentioned my passion for astronomy and my then-recent visit to the Lomnický štít Observatory. The editor asked me to send him some photos from my trip. I sent him few photos and he re-sent them to Astronomy Now magazine. One of thecame a „Picture of the Month”. Three months later, during my language stayLondon, I visited the most famous astro-shop in the city. In addition to a number of different telescopes, there were older numbers of Astronomy Now too. And among them also the one with my photo in it. When I explained this to the salesman in broken English, he gave it to me with the words: „Happy Christmas!”

How did you get to a language course in London?

After returning from the military service, I took every opportunity to travel and get to know the surrounding countries. And when I had visited them, others could come. After the velvet revolution, since 1990, it has been easier to travel to western countries. It was no longer necessary to stand in line in front of the travel agency all night, hoping that the places would not be sold out until you got to your turn. So in 1990 I signed up for a coach tour of Western Europe. In less than two weeks we visited France, England, the Netherlands and Germany.

In London, we had a free time for about two hours. I decided to visit my favourite music editors at the BBC. We talked, besides pop music, also about learning English. They advised me to attend a language course in London. They convinced me that it would be significantly more effective than studying at home. After three years of studying at a language school in Bratislava, on in this trip I found out that my English was very weak. I had mastered the words, understood written text, but I could not communicate at all.

In addition to a nu of LPs, they also gave me a brochure with a list of language schools in London. When I got home, I asked the language schools for a quote. In the end, I chose the cheapest school and enrolled for a stay. The total cost for my four weeks course was in the amount of my half year’s wages. They were right at the BBC, in a month´ s time I improved my knowledge of language more than during a year's course at home. I had lost my shyness and started to communicate.

So was it a reasonable investment?

Definitely yes. English knowledge came in handy later, when I started to focus more intensively on astronomy again. Firstly, at reading English texts on the internet and also when I communicate via emails. In addition, thanks to my stay, I got into a new hobby, arranging language stays.

Upon my return, I described my experience with the language course in London to a weekly magazine, TREND. The article caught the eye and a few people wanted more advice. I realized that if I could arrange my own stay, I could do it for others too. Between the first clients I „sent” to London was my high school classmate, then his brother, and gradually others. Over time, new destinations were added: Malta, Sydney, San Francisco, Los Angeles, Vancouver and Honululu. I was pleased to help them not only to improve their English, but also to gain new experiences. The biggest reward for me was to listbout their adventures when they returned.

Did you considernging your hobby for a living?

Sometimes, but I didn't dare. When I had several clients at once, I was tempted. You know, it's a seasonal business; the commissions would feed me two or three months, and what would I do then? How would I pay my bills? But as a hobby, it did aid us in improving the family budget.

In 2005, after decades, you return to astronomy. If you had to determine the moment of your re-initiation into the field, what would it be?

The internet became more popular in the second half of the 90s. It gradually became known to the astronomical community, too, and at the same time it was more & more accessible to households. I started looking for information about the universe there. Sometime at the end of 2004, I came across the FMO (Fast Moving Objects) Spacewatch project on the internet. Astronomers searched for near-Earth asteroids from the Kitt Peak Observatory in Arizona, USA. Due to the large number of observations, they called for help in data evaluation. Volunteers from all over the world could participate in the search and check online for currently acquired images for unknown NEOs. If a fast-moving object was detected on images by a volunteer, the astronomer immediately learned about it and he provided a subsequent observation to confirm the discovery.

I was intrigued. Although they were not comets, there was a chance for discoveriend you even don´t need your own telescope! You only need fast internet and a l PC monitor. It took me a while to obtain it. On July 4, 2005, the day when the Deep Impact spacecraft was closest to Comet Tempel and its projectile hit the comet's surface, I began my search. I would call this moment as my comeback. restart. I started getting up an hour earlier than before and eagerly awaited for fresh data from Arizona. I viewed about fifty images when I came across my first near-Earth asteroid 2005 QP87 on the last day of August. Less than two months later, I made my second discovery of 2005 UF, and I identified the third asteroid 2005 YK just before Christmas. Who knows whether I could have added another one; unfortunately the project ended in January 2006!

So you were a discoverer of NEOs. What about comet discovery, did you have temptation to hunt for comets after this experience?

Of course, I was tempted. As I said, I was influenced by Comet Kohoutek as a child, and in the summer of 1975 I observed my first comet. It was comet C/1975 N1 (Kobayashi-Berger-Milon). I heard about its discovery on the radio, so I tried to find it with my 5-cm lens telescope, which I had made shortly in prior. My interest in comets intensified even more in March 1976, when comet C/1975 V1 (West) shone in the morning sky. It was amazing. I had a 17-cm Newtonian telescope made and began to search the sky. I soon understood that with this instrument, and only 25 km from the lights oatislava, comet discovery is practically impossible. I gave up hunting. With thO Spacewatch project, the long-forgotten desire for discoveries had returned. And the success with three NEOs had further increased my interest. Although they were not comets, the feeling of discovery was pleasant.

Success encouraged you, so you wanted more discoveries. Then you found out about SkyMorph image archive. How did you learn about it?

At the FMO discussion forum, someone mentioned about the SkyMorph archive. There you can search for asteroids that have escaped from attention of professionals. The hunger for discovery lasted, and the archive seemed a logical next step to me. However, it was a completely different system than FMO, and at first I couldn't do it. It took me almost half a year to master the techniques of the search.

I am not a great speaker, I always prefer to listen and say only the essentials. When I was young, I was ashamed to ask questions or talk to a larger group of people. When electronic mail came up, it cured my shyness. Today, almost everyone uses email communication. So I started to asking questions to more experienced people who had worked successfully with the archive. I got many valuable tips this way from Marco Langbroek, Krisztián Sárneczky, Rob Matson, Quanzhi Ye and Andrew Lowe.

So, from September 2006, I started to count my own discoveries. This new activity developed almost up to an obsession; I lost the track of the tim it. And for three years, I hardly stopped. The result was more than 150 new asids designations.

Didn´t the joy of discovery disappear after so many discoveries?

Despite the number of discoveries, I did not stop enjoying it. That feeling remained, I was happy with every new designation. However I was wondering how I could step to a higher level, to real-time observation and hunting. On the Internet, I came across an offer of rental telescopes from New Mexico, USA. It was the RAS observatory (now known as the iTelescope Observatory). Far from the disturbing lights, quality telescopes and excellent observation conditions were available. Their services would allow me to hunt for asteroids from the real-time night sky.

So was there a time for change after three years?

Yes, you can say so. But I hesitated for a long time. I had to carefully consider if I could afford it. Unfortunately, our salaries do not match up to those rental prices of the advanced setups they have. In the end, I couldn't resist the temptation. I started observing with a 25-cm telescope attached with a CCD camera. For my target, I chose an asteroid I found in the SkyMorph archive. It was approaching the most suitable position for observation in October 2009. And I successfully observed it.

After this experience I dared to undertake a more difficult task – to find a new one. Few days after the full Moon, I aimed the telescope at the selectedr field. Three months passed without result, however, in January 2010 success fly came. I found two asteroids: 2010 AB4 and 2010 AQ39. Another four I added in February. Later, I started observing from another location that RAS virtual observatory offered, from Siding Spring in Australia. I assumed that there would be less competition and a higher chance of finding something interesting. In October 2010, however, a „cold shower” from the MPC (Minor Planet Centre) came for asteroid hunters. They had changed the rules for acknowledging discoveries.

How did they change them?

According to that new rule, the credit for the discovery would be given to the one whose observations would be the first in the year when the minor planet was first captured on at least two nights. Let's say, you found a new asteroid and followed it for a month. If it turned out later that someone observed it earlier, even only for two days, he would get the credit. As a result, since then, the chances of discovery for amateurs have dropped significantly compared to the professional astronomers.

Discovery image of NEO: 2005 QP87. Photo: FMO Spacewatch
Discovery image of NEO: 2005 QP87.

Did this modification affect you?

No, it didn't affect me at all. At that time, I already had enough discoveries, and the passion drove me on. It di matter if I had 10 or 500 asteroids in my „account”. I took it that my obstions helped expand our knowledge of asteroids, and my data could help refine minor planets orbits and speed up their numbering process.

In the same year, you started to cooperate with astronomers from the Konkoly Observatory in Hungary. How did this happen?

After describing my experience of observation through the RAS (virtual observatory) from Australia on my website, I was contacted by the already-mentioned Krisztián Sárneczky, a successful asteroid hunter. We had already exchanged a few emails earlier, in which he had advised me about SkyMorph hunting. He asked me whether I could observe his minor planet 2007 YA4 from Siding Spring, which could be numbered soon, thanks to fresh observations. I observed the asteroid and it actually got its number the following month.

The Konkoly Observatory in the Mátra Mountains, at Piszkéstető, is the largest professional observatory in Hungary. Among other instruments, they have a 60-cm Schmidt telescope. It is also used to observe asteroids, which Sárneczky deals with. So one observation from Siding Spring was an admission to your collaboration?

In August 2010, a new, more powerful CCD camera was attached to the Schmidt telescope. The new setup began producing so many images that they were unable to process all data immediately. They knew I had experience with data processing, so they asked or cooperation. I did not hesitate; such an offer could not be rejected.

TRONG> How did the cooperation go in practice?

First few months, I traveled to the observatory, since later I have been working from home. I did the processing and measuring manually, later Krisztián started using the software for the initial inspection and I remained as a "follow-up" inspector for objects that the software did not find. The human eye recognizes about 1 magnitude dimmer objects than the computer and also picks up those that overlap with stars in the background.

The fact that the follow-up inspection is useful became clear in June 2012, when I found our first near-Earth asteroid 2012 LG11. The software overlooked it, even though it was a „bright” object of 18th magnitude. In 2018, I found the second NEO 2018 TY5. So far, I have obtained a total of 170 designations, 10 of which already have a catalog number. Hundreds more are waiting to be identified, although the chances of obtaining discovery credits are low for the changed rules in the MPC.

Let's stay in the year 2010 and also at the Piszkéstető Observatory. There you learned about another accessible image archive. It was the Sloan Digital Sky Survey (SDSS). How could be this archive be useful for asteroidal research?

The SDSS was originally a supernova research project and it ran from 2000 to 2008 with a 2.5-m telescope. With this, you can see stars up to the 22nd magnitude on images. Data obtained in this project can be used for asteroid astrometry. Krián showed me how to work with the archive. He used it to search there for precovery observations for his own discoveries, thus speeding up the process of obtaining a definitive number. And so I started doing it, too.

Does it make sense to focus on twenty-year-old data? Isn't it a waste of time?

Absolutely not. As my activity in the NEAT archive (Near Earth Asteroid Tracking) declined, the time spent working with the SDSS archive increased. After I checked the SDSS archive for precovery observations of my own asteroids, I considered what to do next. I chose systematic work to check all images taken during one specific night, November 11, 2001. It took me a long time to go through all 1524 fields. I was surprised how many known asteroids’ positions from these images were not reported in the MPC. I looked for second night observations of those objects. And those positions from two nights, I sent to the MPC. This usually meant a change in discovery credit and improvement of orbits. This way I "stole" credit from various observatories and added them to Apache Point Observatory.

The largest amounts of data from my “survey” were positions of unknown asteroids, there were more than 1,600 objects! Some of them are already in the isolated tracklets file (ITF) at MPC. These are such an observations that MPC could not link to any known asteroids. Even after I deducted these, l more than a thousand objects remained. I have no idea how I will use them. Thjects of the main belt predominate, but there are quite a few of them with a faster movement and several dozen possible candidates for NEOs. As the observed arc is only 4.8 minutes long, the reliability of the data is terribly low. And so, linking to other data is very questionable and uncertain. So far, I have archived this acquired data, and what happens to it will be seen in the future.

You started searching for near-Earth asteroids in FMO Spacewatch project and continued to hunt for new asteroids from SkyMorph archive. Then you switched to search via remote telescopes in attractive locations, and in the same year you started cooperation with Hungarian astronomers. Working with archival data from SDSS, isn’t it a step back?

I do not think so. Having your own telescope, let´s say located in Siding Spring within the iTelescope observatory, would be certainly better, but the SDSS archive offers so much valuable data that it would be a mistake not to process it. Originally asteroidal data on images were taken as noise, but from astrometry point-of-view they are very useful.

I assume that it is similar also in other archives, such Pan-STARRS, ZTF, DECam ... Those data could help in re-ordering of data in the MPC. If the observations obtained in this way could be linked to a large number of single-position bodies, possibly even with two nighter objects, we could move themo multi-opposition bodies, and thus make some order in the asteroidal orbital d However, this task is probably not possible for one person. I consider this a great challenge for experienced amateurs.

What type of observations do you prefer lately?

It is searching within the SDSS archive. But I'm also attracted to the Pan-STARRS archive, which has much fresher data, and I assume that the linking of observations would also be better than with SDSS.

Book from 1884: Die Kometen und Meteore. Photo: S. Kürti
Book from 1884: Die Kometen und Meteore.

In the introduction, you mentioned the magazines Říše hvězd and KOZMOS. Did they provide you with enough information in the beginning?

At that time, yes. Gradually, I began to build my astronomical library. In 1976, an advertisement appeared in the Říše hvězd about the sale of older issues of the magazine from 1943 - 1952. I did not hesitate for a moment and decided to spend all my savings from the summer job on this "astronomical" treasure. And with the rest of the price, my parents helped me. So I had with me what to read for a long time. I always tend to lose track of time with a book and between books. I like to visit bookstores on every possible occasion, and so this way my collection of astronomical literature has ually grown. I consider two books, published in 1878 and 1884, to be my most vale catches.

You have been interviewing astronomers from all over the world for ten years and you have published them on your website and in KOZMOS magazine. How did this start?

I came up with the idea during my first visit to the Konkoly Observatory at Piszkéstető. My host, Krisztián Sárneczky, was curious about how I got into astronomy, he was interested in what I was doing. I also wanted to know the details of his career, his journey from childhood to Piszkéstető. It occurred to me then, that I would present him in the form of an interview. He agreed with the idea. When I got home, I wrote down my questions and he answered them immediately. In a few days it was done and to my surprise it was also accepted by magazine KOZMOS. I came to the conclusion that the presentation of talented astronomers could be an interesting section of my website. Until then, I wrote there about Czechoslovak comets, their discoverers and about asteroids. Gradually, I approached others and so interviews began to arise. I tried to present them comprehensively, from the beginning, through the milestones of their career to their greatest successes.

Discoverer of first interplanetary comet, G. Borisov and S. Kürti in Vienna,2020
Discoverer of first intenetary comet, G. Borisov and S. Kürti in Vienna,2020. Photo: S. Kürti archivev>

How did you choose the people to interview?

Everyone has to captivate me with something. At first, I focused on those who devoted themselves to asteroids and comets. I was already in touch with several of them, thanks to the SkyMorph archive. Later, I dared to contact people from other fields of astronomy. Not everyone eventually agrees with the interview request, though.

Can you mention some astronomers who inspired you and were your idols?

I admire many who have done exceptional things. I especially admire Antonín Bečvář and Robert Burnham Jr. Both had a hard and moving life, yet with their perseverance and patience they created exceptional work and their results were used by amateur astronomers around the world for many years. I mean Bečvář's Skalnaté Pleso Atlas of the Heavens and Burnham's Celestial handbook 1 - 3.

What do you consider as your greatest achievement?

I am most proud of the interviews. Imagine, I was an unknown amateur astronomer and I dared to ask renown astronomers. I sought after Luboš Kohoutek, the discoverer of the famous comet, and was able to interview him. And other successful comet hunters. I was pleased when the recommendations for my interviews appeared on the internet. Some have even been published in astronomy journals abroad.

I also appreciate the opporty to name the asteroids. From a scientific point of view, the benefit of the dvery of the main belt asteroids is actually almost zero. But thanks to that, as a discoverer, I was able to name few minor planets and show respect to several people in this way for what they have accomplished, whether in astronomy or in other fields. Not everyone and not all professional astronomers at all have such a privilege.

You named more than twenty asteroids. Thanks to your proposals, today we have minor planets like Nové Zámky, Kolonica, Demitra, Popluhár, or Tatarka. In addition to them, between amongst asteroids’ names, there is your wife and daughter, there are well-known and lesser-known astronomers, or a couple of French singers. The reason for each choice can be different. Why did you finally choose these ones?

Each name has a different reason why I chose it. I will mention one for all. I named one of my discoveries after the Slovak physicist Rudolf Hajossy. I am his former student and I still remember his reassurance of the students on the corrective exams in physics:

"Not everyone has to be a successful physicist. There are other professions. Each requires different talents. For example, the one-legged does not have much hope for Olympic gold in the high jump, but that does not mean that he could not be excellent in another field. You just have to find it.”

I did not become a professional physicist or astrer, but his advice stuck in my memory and I finally found my field, even after  years of searching.

In addition, you were the initiator of several asteroidal namings, although they weren’t your discoveries ...

When I focused on Czechoslovak comets and their discoverers for my website, I also worked on Zdeňka Vávrová. She was a collaborator of Antonín Mrkos at Kleť Obserrvatory, and in the course of 20 years she discovered almost 80 asteroids, and she also has one comet in her ‘account‘. She had many unnamed discoveries, and when I met her, I suggested that I could help to communicate with her proposals. At the same time, I recommended a few people who would deserve to have an asteroid named after them. So I mentioned Miloslav Druckmüller, Petr Horálek, Martin Mašek, and also Miro Žbirka.

Your name is among the named minor planets, too. Asteroids, unlike comets, cannot be named after the discoverer. How did you get there?

When I started hunting for asteroids, I didn't know about acquiring the possibility of naming asteroids on others at all. However, when my first asteroids got a catalog number, which is actually a necessary condition for naming, it occurred to me that it would be nice to name them. So I contacted astronomers at the NEAT Observatory to ask if I could suggest names for these discoveries. They agreed, and so I soon proposed three names to them. I suggested naming the very firster my wife, the second after the Dutch amateur astronomer Marco Langbroek, and third after Nové Zámky, after the town where I live. Langbroek was the one who advised me the most on how to work with the SkyMorph archive. The name surprised him a lot. In turn, he surprised me by asking if I agreed that he whould name the asteroid after me. I was not against it, so soon my name was added, too.

The view of the sky sometimes brings unforgettable moments. Undoubtedly you also had several such experiences. Is there a celestial phenomenon missing from your list?

There were many memorable moments. Comet West in the spring of 1976, or the solar eclipse at Lake Balaton, Hungary, in 1999. However, there are still a few things I have never experienced before. I am fascinated by the beautiful images of aurora borealis. I am sure that being a personal participant or experiencer in this phenomenon is a much stronger and more emotional moment than a photo or video can convey. I would like to experience such a “heavenly performance”. It would also be nice to see another total solar eclipse, a meteor shower, or a starry sky from the southern hemisphere with Magellanic Clouds.

Aurora borealis from Tromso, Norway, Oct. 2019.
Aurora borealis from Tromso, Norway, Oct. 2019. Photo: T. Csörgei



I have perfect relaxation during the moonless nights in our garden, looking at the clear sky from a rocking chair, smoothing our cat in my lap, which is happy to purr! At that moment, if I could, I would join him, too.

Nové Zámky, Slovakia, 2020 December 13