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00:36Hello and welcome to the podcast of Sky and Space
00:38for a new show dedicated to the ephemeral.
00:41I am David Fossé and in this month of February 2025
00:43in the company of Cyril Viandbaum and Sébastien Fontaine,
00:45here are the celestial spectacles that I advise you to observe.
00:49Saturn, Venus and the Moon form a beautiful trio, the first.
00:53Jupiter moves not far from the Hyades, the third.
00:56The Moon flutters Mars, the ninth.
00:59Ganymede and Europe project their shadow on Jupiter, the twenty-fifth.
01:02And a very thin crescent of the Moon is visible to the west, the twenty-eighth.
01:06To comment on these events, Cyril Viandbaum and Sébastien Fontaine
01:09will accompany me as every month.
01:10You can also discover their chronicles
01:12as well as their heartbeats at the end of the show.
01:18Hello gentlemen.
01:19Hello.
01:19Hello.
01:20So Sébastien, we start without waiting
01:22with your monthly chronicle.
01:24Remember that every month you reward us with a little story
01:26linked to the great history of astronomy.
01:29And this month, it is a question of...
01:31Lots of little stories.
01:32We resume our celestial walks that we initiated a few numbers ago.
01:36Remember, we walk in the outskirts of Paris.
01:39I don't talk too much about solar calendars
01:41because there are really a lot.
01:42We will, I think, later have a show dedicated to calendars.
01:44And here we resume our walk in the second outskirts.
01:48We go to the side of Saint-Sauveur Street, at number 12 of the street.
01:51And we are interested in the facade of the Hotel Particulier Famini,
01:54an old meeting house.
01:56So a gallant rendezvous, of course, you can imagine.
01:59And we can admire between the two windows
02:01of the second floor of this meeting house
02:04the remains of a meridian.
02:06At the time, there were a lot of meridians in cities and villages.
02:09Meridians of use, public meridians often,
02:12which functioned to allow people to adjust their watches.
02:16We found a lot of these meridians between the 17th century and the 19th century.
02:20And so we imagine very well these gentlemen, for example,
02:22who, while waiting for the ladies,
02:23adjusted their watches at this address of 12 Saint-Sauveur Street.
02:28We leave the second outskirts,
02:30where I did not find much to put us under the tooth
02:32from an astronomical point of view, in any case.
02:34So we go to the third outskirts,
02:35on the side of Bordas Street, we are on the side of the business areas.
02:39And so we are interested in Charles Bordas,
02:41born in 1733, born and died in 1791.
02:45He is an explorer, a member of the Bureau des Longitudes,
02:48who invented the circle of reflection.
02:50It is the evolution of sextant, finally,
02:52which used an entire circle,
02:54instead of using only a sector of 60 degrees.
02:56We gain in precision to make astronomical surveys.
02:59A lunar crater also bears its name,
03:01a crater of about 45 km in diameter,
03:04which is slightly to the south of the Sea of Fertility.
03:08Then we continue the walk,
03:09we go to the side, so in the swamp,
03:11square Georges Quint.
03:13And on the back of the private hotel,
03:15the Saint-Fargeau Hotel,
03:16we can admire two triangular frontons,
03:19richly decorated, engraved,
03:21with a fronton dedicated to the Middle Ages,
03:23with allegorical figures of the passing time and sabliers.
03:27And then a second fronton,
03:28where we have rather a tribute to the real solar time,
03:32with allegorical figures of truth and the sun.
03:36So that's it, it's something dedicated to time.
03:37But it's interesting to see his works
03:39with figures of Uranus, for example,
03:41which we regularly see
03:42on the frontons of the Parisian Imols,
03:45and in Lyon, by the way.
03:47We continue the walk,
03:49we go to the side of the rue Saint-Martin,
03:52and there we arrive at the Conservatoire National des Arts et Métiers.
03:55So a conservatory, but also a museum,
03:59with temporary and permanent exhibitions, of course.
04:03So we are in the former royal priory of Saint-Martin-des-Champs,
04:07created in 1794 by Abbot Grégoire.
04:10This place therefore becomes a conservation center.
04:14It was Grégoire, Abbot Grégoire,
04:15who had claimed the abolition of privileges,
04:17the abolition of slavery,
04:19and who claimed universal male suffrage exclusively.
04:24In any case, from 1794,
04:26the CNAM is therefore a place of storage and conservation
04:29of machines, tools, books.
04:32Also, we must not neglect
04:33that there is a very, very large collection of works
04:35and manuscripts, plans, diagrams,
04:37very old, sometimes, in the cellars of the arts and trades.
04:40And so all these objects were explained by demonstrators.
04:44It's a bit like the City of Science,
04:45where you can discover things ahead of time, in the end.
04:47And so the public came,
04:49often very well dressed, very chic,
04:52to discover things, arts and techniques,
04:55since that's the term we still use today
04:58to define this place.
05:00And of course, if you have the opportunity
05:02either to follow a teaching or to visit the museum,
05:06you go through the old chapel,
05:07where the magnificent pendulum of Foucault is enshrined,
05:11which is really fabulous to see, to see it swing.
05:17So that's it for this third round.
05:19So here is a fabulous museum,
05:21where you can also take the time to visit its courtyard
05:25while having lunch or drinking a tea.
05:28And you will also have the opportunity to see
05:29some sunsets in the courtyard of the Arts and Trades.
05:33Very good. So if you are on vacation this month of February in Paris,
05:36take advantage of these advice from Sébastien Fontané.
05:38If you are Parisian, of course.
05:40I'm sure you've never noticed,
05:42in our streets, all these pretty sunscreens,
05:46frontons linked to astronomy.
05:49And thank you. So we look forward to the next
05:51Parisian Astronomical Walk.
05:54We move on to the first appointment to report
05:57in this month of February.
05:58The pretty trio formed by Saturn, the Moon and Venus
06:01on February 1st.
06:02It's twilight, so three very bright stars.
06:07Cyril, what will be the phase of the Moon that day?
06:0912%.
06:12So you have to observe on the west horizon.
06:15The Moon is setting, around 7 p.m.
06:19it will be 23 degrees above the horizon.
06:21If you look on the wrong side, on the east side,
06:24you have a red dot, it's Mars.
06:26So we can normally differentiate it.
06:29So you have Venus,
06:33you have the Moon and Saturn, so a pretty trio.
06:37Above the Moon, you have Venus,
06:404 degrees above, so 8 diameters of the Moon.
06:42And then below, at 7 degrees, you have the planet Saturn.
06:47So it's worth looking at it naked,
06:49it's always nice.
06:51And then if you have a small pair of glasses,
06:55a pair of binoculars, or a better instrument,
06:57of course, it's worth going from one to the other.
06:59It's always nice to look at the twilight,
07:04to see how the rings are.
07:06As you remember, they are flattening a little bit.
07:09And then you will always see a first quarter
07:12of the planet Venus.
07:15So maybe we can quickly recall their distance,
07:18because there we have a nice perspective effect.
07:20Yes, yes, yes.
07:22There is an order, of course.
07:25So to recall the Earth-Sun distance,
07:28it's 150 million kilometers.
07:30Venus is half, in the end, it's 77 million kilometers.
07:35The Moon is 380,000 kilometers.
07:40So we are no longer in millions,
07:42we are in kilometers.
07:43And then Saturn, it becomes complete madness,
07:45since it's a little over 1.4 billion kilometers.
07:50So if I bring it back in Earth-Sun distance,
07:54it's pretty funny,
07:55since if the Earth-Sun distance is 1,
07:58it means that in fact it is half this distance
08:02to go to Venus.
08:04400 times smaller to go to the Moon.
08:08And Saturn, there it's madness.
08:10It's 9,000 times the Earth-Sun distance.
08:12Very good.
08:13So three objects at very different distances from us
08:15and which are all grouped together
08:17in the same corner of the sky.
08:18It's February 1st.
08:20We move on to the 3.
08:21The Jupiter 3 ends its retrograde loop
08:24and moves in the Amadeus.
08:27So Sébastien, this is a question for you.
08:29What is a retrograde loop
08:31for the people who will listen to us for the first time?
08:34Explain all this to us.
08:36It's an apparent movement.
08:37Already, we know that when we look at a planet,
08:39whatever it is in the sky,
08:40it moves slowly through the zodiac
08:42following quite closely the ecliptic,
08:44the plan of the Earth's orbit projected into the sky.
08:48To be more precise,
08:50the ecliptic is the apparent trajectory of the Sun.
08:53And so for several months,
08:55we have a planet that moves slowly
08:57through the zodiac,
08:59the Moon during the month.
09:00And then, regularly,
09:01the planets tend to turn around
09:03for a few weeks, a few days.
09:05It will depend on the planets.
09:07And in the case of our Jupiter,
09:09it takes 121 days to retrograde.
09:11So it moves backwards in the sky.
09:13It moves back before going back in the normal direction.
09:16And so that was a big puzzle
09:18in the history of science.
09:20How to explain this retrograde phenomenon?
09:22Very well known with the planet Mars
09:24which, every two years,
09:26shows this retrograde loop.
09:29Today, we can easily explain it.
09:31It's because all the planets revolve
09:33around the Sun, but at different speeds.
09:35And when the Earth, which revolves
09:37around the Sun in a year,
09:39comes to double a slower planet,
09:41seen from the Earth, we have the feeling
09:43that this planet is going backwards.
09:45A bit like when we are in a car,
09:47we double on the highway a car
09:49that goes a little slower than us,
09:51we can be convinced that the car,
09:53we are not doubling it,
09:55but it is the one that moves backwards
09:57So that's what happens for Jupiter.
09:59It arrives at the end of its retrograde loop.
10:01It will go back in the right direction
10:03from now on.
10:05Very well, hence this immobilization
10:07in the Madagascar.
10:09But to observe this immobilization,
10:11we must have already observed that the planet
10:13was moving in the sky.
10:15Yes, the thing is to look at it a little bit before.
10:17You are aware now that it exists.
10:19Each planet presents this type of
10:21almost anomaly, in the end.
10:23But it's very interesting with Mars
10:25because from a historical point of view,
10:27this is where we learned a lot.
10:29For a long time, we had to match
10:31these retrograde loops with the will
10:33that made the Earth the center of the cosmos.
10:35It was geocentrism, dear to our hearts.
10:37And so,
10:39we had invented a different
10:41epicycle system,
10:43orbit systems embedded in each other,
10:45systems to save appearances
10:47that kept the Earth at the center
10:49of the system, of the world,
10:51but which allowed to explain
10:53these loops in the sky.
10:55We realized that it was very complicated.
10:57We added orbits in orbits
10:59to try to realize observations.
11:01We couldn't do it.
11:03And finally, with the arrival of Copernicus,
11:05we realized that there was a very simple solution
11:07to explain this. It was to rotate the planets
11:09not around the Earth, but around the Sun.
11:11And from a schematic point of view,
11:13we explained very skillfully,
11:15in a very beautiful way,
11:17the retrograde loops of the planets.
11:19So it's true that the geocentric
11:21and the geocentric
11:23were helped by
11:25the observation of the retrograde loops
11:27of Mars, Jupiter and the others.
11:29Geocentric and geocentric, I think.
11:31Cyril?
11:33Mars is currently in the Gemini.
11:35Gemini is Castor and Bolux,
11:37two very bright stars.
11:39So you can have fun for several weeks
11:41either to take a photo,
11:43the same photo every two evenings,
11:45or simply to point
11:47by the position of this planet,
11:50this red dot,
11:52compared to Castor and Bolux.
11:54And you will see this movement.
11:56And what is interesting is that there is also an acceleration.
11:58The times are different.
12:00You will see that all of a sudden, it accelerates well.
12:02For the same duration of a landmark,
12:04the distance on the celestial route
12:06is much more important.
12:08So an opportunity to realize that, yes,
12:10the planets move in the sky
12:12and sometimes even make a U-turn.
12:14Let's move on to 9.
12:16We were talking about Mars,
12:18or we could rather say that the Moon is frothing Mars,
12:20because the Moon moves faster in the sky
12:22than Mars.
12:24And in Scandinavia, I think our satellite
12:26is hiding the red planet. Cyril, we won't see that.
12:28Yes, we won't see that.
12:30We will have to wait
12:32until 8.15 p.m.
12:34on February 9th
12:36for the Moon to froth Mars.
12:38I'm in the right direction.
12:40But at about 1°C.
12:42Basically, it's two diameters of the Moon.
12:44If you go to Scandinavia, if you aim for Stockholm,
12:46you are almost at the limit.
12:48You are not far, because you are
12:50almost at 60° latitude.
12:52And at that moment, if you go north of Stockholm,
12:54you have to go up a little bit,
12:56you could almost make the very beautiful photo
12:58that Thierry Legault had taken
13:00a few years ago,
13:02where we have Mars
13:04that comes to froth
13:06the edge of the Moon.
13:08And this image is completely
13:10dazzling,
13:12I don't know how to say it,
13:14because you really have
13:16a kind of Martian tangent
13:18that comes to froth the Moon.
13:20So you will have to go
13:22north of Stockholm,
13:24take a ticket and go up a little bit,
13:26because in Stockholm
13:28it will be just a little bit
13:30below, there will be a few
13:32diameters of Mars.
13:34These images are made,
13:36at the time, Thierry Legault
13:38had made them in video,
13:40so it's the best technique to film the phenomenon
13:42and to get the right images.
13:44Unfortunately, in France, we won't be able to have
13:46this occultation, but in any case,
13:48Mars, very close to the Moon, it's quite pretty,
13:50even if it's only at night, I guess.
13:52Yes, at night,
13:54you will actually see
13:56a Moon with
13:58a little red dot on it,
14:00but with a telescope, it's funny to go from one to the other,
14:02and since they are only at 1°,
14:04you don't get to see
14:06the two celestial objects at the same time,
14:08it's always nice.
14:10On the 25th, an observation
14:12to be made with the Ganymede telescope
14:14and Europe simultaneously project
14:16their shadow on Jupiter.
14:18We rarely talk about these phenomena
14:20on Jupiter.
14:22Sébastien, what diameter do you need
14:24to be able to observe these shadows?
14:26We can start to unseal the shadows
14:28with a 60mm initiating lens,
14:30but honestly, it's much more comfortable
14:32with a 200mm telescope,
14:34you have to enlarge it a little bit,
14:36at least 150 times, to be able to see these shadows.
14:38So, here we have a double
14:40shadow projection on Jupiter,
14:42but be careful, because the double projection
14:44won't last very long,
14:46since Ganymede projects
14:48its shadow on Jupiter from 8pm
14:50to 10pm,
14:52and Europe
14:54from 10pm to 10.30pm,
14:56so we have 10 minutes
14:58where the two shadows are simultaneously projected
15:00on Jupiter, but the two shadows
15:02are projected close to Jupiter's limb,
15:04so with a fairly large
15:06diameter,
15:08and a rather low contrast.
15:10So it's important to have a fairly open,
15:12bright instrument,
15:14with a fairly large diameter,
15:16and a very transparent sky
15:18to hope to see both shadows.
15:20But in any case, try the observation,
15:22because it's worth a look.
15:24At worst, you'll see one shadow at a time,
15:26and another at a time, that's for sure,
15:28even with a really
15:30initiating instrument.
15:32Now it's up to you to see if both are visible at the same time.
15:34So, with a dobson,
15:36I hope to see both, but in any case,
15:38I'm sure I'll see one and the other.
15:40I liked your
15:42if it's sunny,
15:44we can feel the instrument that has suffered a lot in recent months.
15:46How many years has it been?
15:48I remember I did two years of Cherbourg before,
15:50sorry for the Cherbourgeois, I kiss you.
15:52We saw in 2024,
15:54the weather remained only one week
15:56in August, in the end.
15:58So if it's sunny,
16:00but if it's sunny anyway,
16:02you don't take too many pictures.
16:04What kind of equipment do you need to take this Jupiter picture?
16:06With both eyes, it seems difficult,
16:08but maybe it's better with a picture.
16:10You need waterproof equipment,
16:12to start with.
16:14There is
16:16the simple way,
16:18completely random,
16:20you take your smartphone behind an eyepiece,
16:22and you try to do it.
16:24You have a souvenir photo, which is not necessarily
16:26high definition, but it works,
16:28and you can show your neighbor
16:30you have to be able to do the focus,
16:32it's better to have a system that hooks
16:34the smartphone directly
16:36to the back of the eyepiece,
16:38it's a kind of tweezers.
16:40Otherwise, more seriously,
16:42the first important thing
16:44is to have
16:46the right focal length,
16:48the right focal ratio
16:50on the instrument's diameter.
16:52What you need to know is that
16:54the more the antenna,
16:56the more the instrument's diameter is important,
16:58the more resolution you have,
17:00you have a kind of separating power
17:02that will separate
17:04two points of relief,
17:06I don't know how to say it,
17:08two details
17:10easier to observe.
17:12The more the diameter is important,
17:14the more you can have a focal length
17:16that is important,
17:18and have very precise details.
17:20There is a formula
17:22when you do planetary photography,
17:24which depends
17:26on the F on D ratio
17:28to be reached,
17:30and especially on the size
17:32of the composite photos
17:34of the sensor.
17:36You can imagine
17:38that a sensor
17:40of a camera,
17:42of a CCD,
17:44is full of small pixels,
17:46let's say,
17:48encoded by each other.
17:50So if you have big pixels
17:52and you send two details
17:54to the same pixel, you don't separate them.
17:56You need to have several pixels separated
17:58in order to have two separate details.
18:00So the formula is
18:02that there is a kind of minimum
18:04to be reached,
18:06that is, this F on D ratio
18:08must be equal to three times
18:10the size of the composite photos,
18:12or for Jupiter,
18:14in general,
18:16we are more of the F on D ratio
18:18which is equal to five times
18:20the size of the composite photos,
18:22and the maximum is that
18:24beyond this value,
18:26it is not even worth doing it
18:28because it will not work,
18:30which is the F on D
18:32which would be equal to eight times
18:34the size of the composite photos.
18:36What is also important
18:38is that the cameras have
18:40different size pixels.
18:42Globally, the small cameras
18:44that we use, or even on cameras,
18:46if we take 3 micron, it works.
18:48It means that you will be
18:50between a ratio of 10
18:52and a ratio of 24.
18:54F on D is 10
18:56or F on D is 24.
18:58So if you are on this,
19:00that is, you take
19:02your instrument diameter
19:04plus the focal length,
19:06you have to be
19:08about 15 on Jupiter
19:10to get something
19:12correct.
19:14What we use now,
19:16it was a trick that
19:18Gérard Therain gave me a long time ago,
19:20which is to use a double focal length,
19:22the double focal length of a camera
19:24that allows you, easily,
19:26without having to have
19:28very clean lenses,
19:30it is quite practical,
19:32these double focal lengths.
19:34Once you have that,
19:36you have determined the instrument,
19:38the focal length you need,
19:40this ratio, roughly,
19:42F on D is 15.
19:44From there,
19:46we could believe that it is the same principle
19:48as usual,
19:50now we rather do a series of photos
19:52or a video sequence,
19:54it is even simpler.
19:56Once we have the video sequence,
19:58we put it in a software
20:00that will allow to sort
20:02those that are beautiful,
20:04that have not taken the turbulence of others,
20:06the software will frame at the same time,
20:08you have a sandwich
20:10full of correct images,
20:12and then you put it directly
20:14in another software
20:16that will allow you to do the image processing
20:18to improve and get the details out.
20:20This is the principle.
20:22In fact, on Jupiter, it is not at all like that.
20:24It's a joke.
20:26In fact, Jupiter is
20:28downright annoying.
20:30In fact, Jupiter rotates very quickly,
20:32we said it last month,
20:34it rotates in 12 hours on itself.
20:36If you make a fairly long video,
20:38what you are taking is not the same
20:40at the beginning as at the end.
20:42It's a gas planet,
20:44so it complicates the game even more.
20:46The principle is the same,
20:48but it's not quite the same software.
20:50Basically, there are free softwares,
20:52among others, WinJup,
20:54that allows you
20:56to select,
20:58to make several video sequences
21:00that last maybe a minute,
21:02so you have so many images
21:04per second to recover,
21:06it recovers the right images,
21:08so it will somehow
21:10arrive, the software,
21:12in addition, it works on the meridian of the planet,
21:14basically, it manages to recalculate
21:16the map of the planet to recognize
21:18the place that is sharp, that is good,
21:20the place that is blurry.
21:22Basically, in an hour,
21:24you will take a first part that wants to make a piece,
21:26another part, etc.
21:28After, you will use
21:30other softwares, like Surface,
21:32which will allow you to do the image processing,
21:34and then often,
21:36you end up on Photoshop to get to
21:38do the thing again.
21:40So it's worth doing it, but it's a nice gas factory,
21:42there are plenty of tutorials,
21:44Jean-Luc Devergne did tutorials,
21:46there are even tutorials
21:48of the different softwares,
21:50so you have to go, it's fun to do,
21:52and then you don't have to
21:54have 10 minutes of images,
21:56you can also do it on 10 images
21:58or 20 images, and it works very well.
22:00A good computer.
22:02Yes, but the softwares are effective,
22:04I can testify that I am not at all an astrophotographer,
22:06I am not an astrophotographer
22:08to take pictures of Jupiter,
22:10which starts to look like Jupiter
22:12with the blue skies,
22:14and indeed with the advice of Jean-Luc Devergne
22:16who published all this in video
22:18on the occasion of one of our out-of-series
22:20dedicated precisely to astrophotography.
22:22We move on to February 28th,
22:24the twilight of February 28th,
22:26the moon, in very thin crescent,
22:28can be searched to the west.
22:30Cyril, it will still be sporty,
22:32the thin crescents of the moon to the west?
22:34Yes, not as simple as that,
22:36because the sun sets at 6.30 pm,
22:38sunset means that it is still day,
22:40it is still a little yellow,
22:42and the moon
22:44sets at 7.15 pm,
22:46so between the two there is 45 minutes,
22:48so it's going to be very, very sporty.
22:50At the time the sun sets,
22:52the moon is 6 degrees above the horizon
22:54and especially its
22:56illumination phase is
22:580.6%, so it's really
23:00very, very, very thin crescent.
23:02So that means that
23:04if it's a little humid,
23:06it's not worth it.
23:08If you don't have a completely clear horizon
23:10in the middle of the west,
23:12it's not worth it either.
23:14Basically, if it has to be, we are still in winter,
23:16it has to be cold and dry,
23:18and there you have a good chance
23:20if your horizon is clear or if you are
23:22a little in Auvergne, a little in height,
23:24with a diving view on the west horizon,
23:26there you can go completely.
23:28So an association for sportsmen
23:30who actually listen to us.
23:32If you succeed in this photo,
23:34because it could be very pretty anyway,
23:36because we have a very, very thin lunar crescent,
23:38send it to us at open at night
23:40at cielespace.fr
23:42It is Jean-Luc Dauvergne who receives the photos
23:44and if he selects it, it will go
23:46in the newspaper.
23:50The time of the photo chronicle
23:52has arrived. Cyril, you keep your word
23:54since you advise us every month
23:56on the best way to immortalize
23:58a celestial phenomenon or a beautiful object in the sky.
24:00And this month, I think you're going to advise us
24:02to fight the cold, because it's also
24:04one of the ways to succeed in the photo.
24:06Yes, it's true that it's terrible.
24:08At night, when we take pictures,
24:10either we have two instruments,
24:12that is, there is one who takes care of everything
24:14by himself, who takes the photo,
24:16and you move around each other to observe.
24:18This is the best solution.
24:20But it does not prevent that in the middle of winter,
24:22we start to feel a little cold.
24:24I don't know if Sébastien knows,
24:26when you have a cold on your feet,
24:28what is it? It's to jump.
24:30It can be to jump, but the basis is
24:32especially to put on a hat.
24:34When you put on a hat, in general,
24:36you have a little less cold at the ends.
24:38In fact, it's friends who showed me this,
24:40who bought this for Christmas.
24:42And it's true that it's pretty funny.
24:44So I tested, quickly.
24:46I tested, but not at night,
24:48not outside. I tested at home,
24:50directly in their shoes.
24:52But basically, it's hot soles.
24:54And so I looked after, but it's completely
24:56crazy, since these heating soles,
24:58there are several kinds.
25:00So there was the chemical one we knew,
25:02that we had in the car, when in general
25:04our kids are small, sometimes there is a problem.
25:06But then, in fact,
25:08you have soles now that are
25:10rechargeable in USB.
25:12That is, you have these soles
25:14that you put at the bottom of your shoes,
25:16which have built-in batteries,
25:18you have charged them during
25:20the day, and all night,
25:22and in fact, it delivers you a temperature
25:24that makes your soles colder.
25:26So there is this one, there is this one,
25:28others that are completely wired.
25:30So it must be less practical.
25:32That is, you have wired them with two batteries
25:34hanging on the soles.
25:36So I don't think it's necessarily the best solution.
25:38And then, in fact,
25:40theirs is even stronger, it is
25:42remote-controlled.
25:44That is, in fact, there are remote controls.
25:46It's not very clever, it's that a remote control
25:48controls the four shoes.
25:50If your feet are cold, a new gadget,
25:52quite fun,
25:54so I think it's worth it.
25:56But a fun gadget, if you are sensitive to your feet,
25:58it's these rechargeable
26:00heating soles.
26:02Incredible, I would never have imagined
26:04that one day we would talk about socks.
26:06It's great.
26:08Maybe it's a gift for the subscribers.
26:10If we reach half the left foot.
26:12If we are flooded with emails
26:14asking for it, we might change it.
26:16Thank you Cyril, frankly, what an idea.
26:18The end of this show
26:20is approaching.
26:22Sébastien, Cyril, it's time to reveal your
26:24favorite of this month.
26:26A star, a book, a space mission, an exhibition, an astronaut,
26:28an instrument, an observation site,
26:30I would have to find others.
26:32You have the choice, in any case, what is your
26:34Sébastien for this month?
26:36So, the heating sole.
26:38I discovered that not long ago.
26:40I find it extraordinary.
26:42There are several versions.
26:44The heating gloves, the heating pants.
26:46It's a real heart attack.
26:48I didn't test it, but we'll talk about it
26:50in a next edition.
26:52My favorite of the month is a book
26:54under the patronage of
26:56Pierre Léna
26:58and Christian Gratalou.
27:00Pierre Léna,
27:02member of the Academy of Sciences,
27:04astronomer.
27:06The book he publishes is the Atlas of the Sky.
27:08Published by Les Arènes.
27:1027 euros, 256 pages.
27:12It's a history book
27:14with a lot of anecdotes,
27:16a fabulous iconography.
27:18It's richly decorated.
27:20We learn 12,000 things.
27:22I think it's going to be a mine
27:24for my future chronicles.
27:26It's really extraordinary.
27:28It's clear, it's very interesting.
27:30We just want to open the next pages
27:32to learn more.
27:34I thought I knew a lot of things.
27:36I discovered a lot.
27:38It's very well told.
27:40There are a lot of anecdotes.
27:42This Atlas of the Sky
27:44was part of a series
27:46of Atlas published by Les Arènes.
27:48I also
27:50worked on
27:52the Atlas of the Earth
27:54and of France.
27:56The version of France is the history of France
27:58but mostly through maps.
28:00We have 375 maps
28:02that tell you the history of the country
28:04and the movements of the people.
28:06There were already books like this.
28:08I think of the book by Georges Duby
28:10It's extraordinary.
28:12It's richly illustrated.
28:14I invite you to start
28:16with the Atlas of the Sky.
28:18Pierre Lennart,
28:20we see him a lot in the series
28:22Tour du Monde, Tour du Ciel
28:24with this extraordinary music
28:26by Georges Delerue.
28:28We still hear the sound of
28:30Michel Serres' voice.
28:32Pierre Lennart became famous
28:34in the 70s
28:36during a flight to Concord
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