Little known constellations: Antlia & Telescope

Antlia, the Pneumatic Machine

the constellation Antlia

Those few who have raised their hand will agree that the Pneumatic Machine is a forgotten or at least unknown constellation since you don't even know where it is in the sky: a glance at the Stellarium map lets you know that it is located just below the Hydra constellation, but since the latter extends longitudinally in a vast area of sky, to find Antlia you have to start from Leo and go south. We'll talk about that later.

Meanwhile it is a modern constellation, not of ancient times, created in the 18th century by the French astronomer Lacaille, who placed in the sky a device that serves to create the void inside a glass bell, as we can see in this image taken from the planisphere of Lacaille.

Antlia, the vacuum machine

Here instead is the pictorial representation of Stellarium

the Antlia according to Stellarium

The name, the story, the myth

Antlia is a constellation of the austral sky, introduced in 1754, by the first astronomer to map systematically

the southern sky Nicolas de Lacaille in the 17th century along with Pyxis.

Its name is a tribute to the machine used to recreate vacuum in the laboratory, the pneumatic machine, the pump instrument invented by the physicist Denis Papin (about 1647-1712).

The word antlia is not a neologism, it is a term of Greek origin associated with a machine, a wheel, which allowed to bring water from one level to another proceeding upwards. The original French full name in de Lacaille's catalogue was Machine Pneumatique, and has always been associated with the main Antlia, perhaps to distinguish this from the ancient Greek machine, and to underline even more the modernity of its origin.

Nearby stars and large stars

In this constellation there are two stars very close to us, well below 20 light years: they are DENIS 1048-3956, a brown dwarf of class M8, placed at a distance of 13.2 al and 2MASS0939-2448 (more simply known as 2MASS J093548-2448279 A), another cold brown dwarf of class T8, probably a binary with another brown dwarf, at a distance of 17 al our sun.

They are two very small stars and to compare their size with something known (the Moon), I took pictures of the two brown dwarfs from a distance of about 400000 km, discovering once again that the Moon (big and bright) actually appears to us as a disk of just half a degree of diameter: the "DENIS" instead covers an area of 7° and more than double the "2MASSeccetera" with its 19° diameter. Given the proximity of the two stars, I went to my Denusiani friends from whose cloudless planet our Sun appears of third magnitude in an area of sky with stars from Andromeda as well as α Centauri. Instead, from the home planet of my friends Duemassoni, the Sun appears in a zone of sky even poorer in stars, with the usual α Centauri near the well-known Altair.

the comparison diagram of the stars of Antlia

In the comparison diagram between the stars of Antlia and other monsters of the sky (for size and notoriety) I have once again inserted two stars of class K, like the well known Aldebaran, but that once again dominate it for size: they are ε Ant, almost twice the size of the Taurus star (64 times our Sun) and α Ant, with 44 times our yellow dwarf. My Epsilanti friends are so happy about this fact that their battle cry is "eAntiamo!", probably of Romanesque origins... who knows.

Deep sky objects

In this small constellation there are some remarkable objects: the first one is a dwarf elliptical or spheroidal galaxy, called Antlia Dwarf Galaxy

the Antlia Dwarf Galaxy

the second object is a beautiful spiral galaxy, the NGC 2997, taken in all its magnificence by the HST

the beautiful galaxy NGC 2997

the last object we see is the elliptical galaxy NGC 3258

the elliptical galaxy NGC 3258

Names and visibility

As it is easy to imagine, the constellation of the Pneumatic Machine does not include stars baptized with a name.

As for its visibility in the sky, at the convenient time used in all the episodes of this series, 9 p.m., it has to be said that from our latitudes it appears low on the horizon (South East) at the end of February, while it culminates in the South around the end of April, at a height above the horizon of about 15°. Finally, it is near the western horizon around the beginning of June, so why not observe it?

The telescope

the Telescope constellation

What is a $telescope$, we should all know, but where it is in the sky very few people know: thanks to the map of Stellarium we can see its location, just below the beautiful tail of Scorpio, which unfortunately at our latitudes always appears quite low on the horizon. But if we take a location in the extreme south of Sicily, Pachino, well known for its cherry tomatoes and that is even present in the city database of Stellarium, well, from there the constellation can even be seen, although low on the horizon. But we'll talk about it at the end, as usual.

The name, the story, the myth

The constellation of the Telescope is a relatively new constellation, having been inserted by Nicholas de La Caille with the name of Télescope, specifying that it was the 'Tubus Astronomicus', the astronomical telescope suspended from a pole.

It is not surprising to find the astronomers' fundamental instrument represented in the sky; observation tubes had been used since ancient times, but the first proof of the existence of a telescope appears in a letter of 1608 from a Committee of Conciliators in Zeeland, Holland. By 1610 Galileo had already achieved magnifications in the order of 20-30 times.

In reality, the size of this constellation was larger than it was later, and today.

For a modern constellation, the only representation I show is the modern one of Stellarium, in which you can see a very modest telescope-toy mounted on a treppiedino

the Telescope according to Stellarium

A nearby star and a large

Said immediately that its stars are weaker than 3.5, like the star α Tel, inside this constellation there is one of the stars near the Sun, Gliese 754, class M4 placed at a distance of 19.3 al from us: my friends Telegliesi sent me the photo of the $campo$ star with in the center a star almost of 4a , surrounded by illustrious celestial objects, such as Capella and other stars of the Auriga, the twins Castor and Pollux with Alpha Centauri and Raccoon.

Telescope star comparison

In the usual diagram of comparison between the few stars of the Telescopium and others already met several times, we find a red supergiant, ξ Tel, of spectral class M1 and with a diameter of 148 times that of the Sun and twice that of the brilliant and well known Rigel: unlike the star of Orion (of 0.15), which is more than 800 al from us, the red giant is more than 1000 al from us and is intrinsically less bright, appearing barely 5a .

ξ Tel viewed from a distance of 10 UA

To show you what this supergiant looks like from the distance of 10 UA, I went very gladly to my Csitelle friends: just think, a planet of women only, which not surprisingly is called Venus! What a disappointment: they are all very unpleasant, sour and grumpy and think nothing but an enviable tan, easily reachable thanks to the proximity of this stellar monster.

But let's leave the facetiousness, passing to some deep sky objects.

Deep sky objects

Let's start the analysis of deep sky objects starting from the spiral galaxy NGC 6850

the galaxy NGC 6850

then we see a really fantastic object, the globular cluster NGC 6584

the globular cluster NGC 6584

and finally two elliptical galaxies: the first is NGC 6861

the galaxy NGC 6861

while the second is NGC 6868

the galaxy NGC 6868


I end my analysis of this small constellation by saying that none of its stars have been baptized with names that do not suggest mobile phone operators (see for example the brightest, α Tel ).

On the visibility I take into consideration this time the charming Sicilian town of Pachino, from which the constellation can be seen culminating in the South, very low on the horizon, less than 10°, at 9 pm of the last days of August, just below Sagittarius, beyond the nice Southern Crown.

Audio Video Little known constellations: Antlia & Telescope
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