Sunday, 30 March 2025

A little ramble through Antlia the Air Pump

 The first of our modern constellations Antlia the Air Pump, and I am afraid it is a very poor example of a constellation as many of the modern ones are. When astronomers refer to modern constellations, they are referring to ones that were created in the 1500s, 1600, or 1700s, compared to what is referred to as classical constellations which have existed for several thousand years.

In theory Antlia can be seen from Britain very low in the sky during spring evenings but as there are no bright stars it is difficult to find.

We owe the formation of this constellation to the French astronomer Abbe Nicolaus de la Caille (1713-1762) who is frequently encountered in connection with certain constellations in the southern sky. He travelled to the Cape of Good Hope in 1750 to chart the southern heavens and in 1763 produced a catalogue of over 10,000 stars which was published posthumously. The catalogue itself was very important it’s just a shame that most of his constellations were not.

He would introduce 14 new constellations to the sky, all in the southern sky and sadly they are all faint and obscure groups and many of them represent what were at the time modern instruments. I can understand why he was trying to promote these new scientific inventions; it is such a shame that the constellations he produced were not bright and spectacular and do not reflect the true scientific importance of the scientific instruments. Antlia was originally called Machine Pneumatique.

With this being a modern constellation there are no myths or legends associated with it.

There were originally 48 constellations the number has now increased to 88 many of these modern constellations are made up of faint stars just to fill in the gaps between the main constellations. Many do have modern sounding names. Abbe Nicolaus de la Caille is guilty of this.

The air pump was created to honour Robert Boyle’s invention of the air pump around 1660.


Antlia can be seen very low in the sky during spring evenings from Britain however there are no bright stars in the constellation, you would need a very clear southern horizon and a very clear sky to be in with a chance of seeing any stars in Antlia. To locate Antila you would need to look below the constellation of the Hydra which is itself a faint constellation. I remember when I lived in the south of England, I did look for the stars of Antlia a few times, but I never saw any.

The brightest star, alpha has magnitude or brightness of only 4.2 the star has no name and is hardly visible to the naked eye even under the best of conditions. It is a K class giant star meaning that it is cooler than the Sun. It is 320 light years away. The other stars in Antlia are even fainter.

Even from the southern hemisphere where it is naturally much higher in the sky there is little to remark about Antlia. If you observed from the southern hemisphere where in theory it is easier to see, the sky will have to be clear any mist or moonlight or light pollution would make Antlia impossible to see.

Antlia is an example of one of these faint and quite irrelevant constellations which if it was removed from the star maps and its stars were transferred to nearby classical constellations no one would notice. However, it has survived all the changes to the lists of constellations over the centuries and was included in the list of constellations defined in 1930 by the International Astronomical Union. This means that you can still find Antlia on all-star charts.

 


                                                   www.theramblingastronomer.co.uk

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