At the end of this article, you will find the different presentations made by the course leaders!

Sep 29, 2023 | News, Projects, Technics

My experience of the 2023 spectro course

August 8th arrival at OHP

Great day to plant setups at the Haute Provence Observatory. Amidst rosemary, myriads of little white snails and other small creatures, I arrived in the community of amateur spectroscopists on August 8, 2023.

Christian BUIL, Valérie DESNOUX, François COCHARD, Olivier GARDE, of course I know them from the Zoom workshops and the CALA forum, but here they are present in flesh and blood, and I feel like the person I was when I started out. Some of my usual confidence and expertise has just been shattered. So I arrive a bit on tiptoe with the prestigious world of amateur spectroscopy before me.

Pierre AIM

I have been a member of the Lyon Ampère astronomy club (Le CALA) since 2018, but I have regularly followed the club through the conferences and public events it has organized since the early 2000s. Having ended a long life of professional travel in 2013 to take up a position in an engineering office in Lyon in 2013, and after widowhood and a total overhaul of my family life with my current partner (who said life is a long quiet river again?), I was finally able to consider re-entering the world of amateur astronomy in 2018. Attracted since my teens to science-fiction literature (the works of Arthur C. Clarke, for example) and to the understanding of astrophysical phenomena and cosmology since the 80s thanks to Hubert Reeves, then Jean-Pierre Luminet and Stephen Hawking in particular (and everything I’ve seen on TV or in the scientific magazines to which I subscribe “Ciel & Espace” and “La Recherche” about Newton, Einstein, Copernicus, Keppler, etc.), my choice of activity at CALA was immediately and without any hesitation directed towards astronomical spectroscopy. ), my choice of activity at CALA was immediately and unhesitatingly oriented towards astronomical spectroscopy. Unfortunately, the COVID years came to delay my spectro journey, which I didn’t really know where to start. So I decided to approach spectroscopy patiently, “taking my time” (but not too patiently either, as I see my future with spectroscopy far beyond my professional life and into infinity…) and to take part as much as possible in the various events organized around this activity (in particular the zoom events organized during the covid period by François and Olivier). It introduced me to the spectro community and led me to the spectro party at OHP this summer.

My arrival at OHP

Christian and Olivier seem very busy with their installation, I am not going to disturb them. Ha, a small friendly group is chatting with Valérie. Come on, I’ll take this opportunity to make a first contact, and ask Valérie if there’s place for a first-timer like me. Damn, I don’t have any experience in astrophotography and that’s a prerequisite, Valérie tells me. Come on, we’re not discouraged, anyway I tell myself that I can’t leave without having learned anything. The following days will show me that the spectro community has a philosophy of sharing and kindness.

Ha, I see Vincent. Hello Vincent, very happy to be at the OHP. A little later, Kevin arrives. I feel a little less alone (from CALA) at the same time.

Well, at work, I have to install my equipment. Here a member of a native species comes to welcome me too:

There you go, part of the installation is done under a Sun in great shape, well supplied with carbon-free hydrogen. The tarpaulin was not an extra purchase (mine is supposed to filter UV, but for infrared, not sure). My folding cart was also a good idea, I think, but my camping table is a green dwarf in the middle of the proud blue or white giants that have settled on the ground!!!

Meanwhile, Kévin plants his setup a few meters from mine.

First afternoon

Everyone in class for the internship presentation. Everyone listens to François.

This year, the internship is essentially focused on the practice of spectroscopy. Workshops, advice, mutual aid and practical application are the common threads for this new edition of the spectro party. This is perfectly in line with my expectations.

Then the presentation of the observation program with Christian….

Yes, thank you, good training also to all participants!!!
We all received a pretty little vial with a USB cap containing information and software that could be useful for us to follow the course and enrich our computer library, Demetra, INTI, Spec INTI, ISIS, Visual Spec, which will be explained throughout the afternoons. Internet access is also allocated to us individually.
Attention to detail, I realize to what extent spectro amateurs operate with scientific and professional rigor.

Well, the first evening arrives with the first workshop on the table and first surprise shared with François who comes to my rescue, my camera does color and not black and white… It will have to be replaced by a black and white later. So I don’t have an acquisition camera, but nothing is lost because a charitable soul in the community, Rémy, will lend me one.

When I spoke of kindness and mutual aid in the spectro community above, it was not to look good in the text.

This is how I will experience a series of technical difficulties that all spectroscopists have encountered during their journey in the quest for the Grail, I am talking about obtaining a calibrated spectrum free of instrumental effects ready to be interpreted.

Here are some rules that I remembered from that first day:

• As in many technical fields, we are in a process of continuous improvement, this is the principle of the Japanese quality method called “Kaizen” which consists of evaluating, validating the relevance and conformity of each step of progression in order to be able to continue on the next step.

• There is a methodology to “catch”, then we forget the instrument and concentrate on the stars.

• We adjust the spectro on the table with the help of the Sun.

• All settings are made during the day

• Keep a logbook (dome notebook, observation program, etc.)

• Organize data (to be kept for centuries!!!)

• A directory per observation session, explanations, data archiving

• The spectroscopist’s mission during the night: put as many photons as possible into the spectroscope slit!!!!

The other days

The days will come one after another for me, each time with new technical problems to solve. Some that I will be able to solve alone and others that will require help. For this, I must again thank François, Yves, Vincent, Kévin, Rémy, Stéphane, Olivier, Daniel. And the whole group for all the friendly and cordial exchanges, truly a great community of enthusiasts.

The week also took place with beautiful and interesting presentations, Shelyak innovations, low resolution spectro, high resolution, Planck curve, Uvex, silicon valley, software, spectroscopes, astrometry, Visual spec, Inti spec, Bess base, base Staros, 2SPOT in Chile…

And naturally the talented and high-level presenters, Christian, Valérie, François, the Nice People team, Olivier, Vincent, Matthieu. What a week !!! I would happily say that there is no amateurism among astronomical spectroscopy enthusiasts


For my part, I learned a lot from this spectro party week. It is a necessary step to meet accomplished spectroscopists and understand the rigor required to practice astronomical spectroscopy. However, it became obvious to me that I lacked preparation in advance, especially with my setup which I only partially mastered (and I am being indulgent in writing this). Still, I can now better discern my road map to achieve a spectrum. Like all learning, you have to devote time, patience and be able to evaluate your progress. Note that the final debriefing was an excellent idea which I am sure will allow me to finalize my roadmap for this year in the hope of returning next year to the OHP. Needless to say, I have plenty to keep me busy…
I also really enjoyed the recreation at the OHP’s 1.93 m telescope, its ELODIE and SOPHIE spectrographs (nice first names, aren’t they?) and the meeting with the history of the detection of first exoplanet at the OHP by Michel MAYOR and Didier QUELOZ. Really impressive to me…

By way of conclusion, thank you again to the beautiful spectro community that I discovered at the OHP, see you next year I hope, and I would end with this thought from Jean Perrin which resonates in the heads of all lovers of sky and the Universe:

Presentations made during the course by the instructors