A little ramble through Canis Minor the Lesser Dog

 In modern mythology Canis Minor is the Lesser Dog constellation that together with Canis Major follows Orion the Hunter across the sky.

It appears not to have been known to the classical Greek astronomers it was simply referred to as rising before his companion star. It is about the time of Ptolemy c100-170 CE that it appears as a separate constellation and is therefore included in the 48 classical constellations.

There does appear to be suggestions that the stars that we refer to as Procyon and Gomeisa in Canis Minor were known to the ancient Mesopotamians as the ‘Twins’ this term dates to around 1100BCE. The Arab astronomers of a thousand years ago called the constellation Al Kalb al Makbudah or the Lesser Dog.

As the constellation is close to Orion it is seen in the winter skies, however as it follows Orion and is higher in the sky than Canis Major it can be seen later in the year into early spring. It’s a small constellation and although it contains Procyon a bright star the rest of the constellation has few bright stars and no clusters or galaxies worth mentioning.

The brightest star is alpha or Procyon or the Small Dog Star. The last of the great Arab astronomers Ulug Beg called the star Al Shamiyyah which together with other sources suggest the name of the Northern Sirius. The Euphratean astronomers called it Palura of the Cylinders, or the Star of the crossing of the Water. This name is given with reference to the River of Heaven or the Milky Way which is very close to Canis Minor. The Chinese call it Nan Ho or the Southern River.

Procyon with a magnitude of 0.3 forms part of what is called the winter triangle with the stars Sirius in Canis Major and Betelgeuse in Orion. Inside this triangle the milky way flows. Procyon is a binary system with the main star being an F class star hotter than the Sun with a small white dwarf companion which was discovered in 1896. This white dwarf is like the white dwarf companion of Sirius, its small and the material that makes it is very dense in nature. Another feature it has with Sirius is that it is relatively close to us, it is only 11.5 light years.

The only other bright star is beta or Gomeisa , there does not appear to be any ancient names attached to the star. The Arab astronomers called it either Al Gamus or Al Murzim which is the same name as Beta Canis Major in both cases the name refers to the whole constellation. Its magnitude in 2.9 and is 160 light years away, and is a B class star hotter than our Sun.

Although the milky way flows through Canis Minor there are no bright star clusters or galaxies, the ones that are here are all very faint and require reasonable size telescopes to see them and are therefore beyond the scope of our little ramble through Canis Minor.

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The Astronomy Show on Drystone Radio

 Join me, Martin Lunn MBE every Monday evening from 7.00 pm-9.00 pm on the award-winning Astronomy Show on Drystone Radio, probably the only regular astronomy show on any radio station in the country. 

I will take my weekly look at the night sky and look at all the latest news in astronomy. There will be the astronomical anniversaries this week plus the latest news from the astronomical societies in the north of England.

The Astronomy Show every Monday evening only on Drystone Radio live online at www.drystoneradio.com DAB radio in Bradford and East Lancashire, or 102 and 103.5 FM and can also be heard later on the Drystone Radio Podcast.

 

Sunspots seen from Reading in 1896 with a Thomas Cooke telescope

 In 1896 the Rev J H Jenkinson of St Mary’s vicarage  Reading, Berks described a series of sunspot drawings he had made between February and August of that year. He used a 4.5 inch Thomas Cooke of York telescope.

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A little ramble through 19th century astronomy - Prizes for the discovery of comets - a report from 1870

 The following circular has been issued by the Imperial Academy of Sciences at Vienna: -

For several years past there have been remarkably few discoveries of comets. The cause of this fact, which seems inconsistent with that of the wider distribution of telescopes suitable for such discoveries, may be due to the special attention that has been given t the small planets. It is, however, much to be regretted that there has been such a slight increase in our knowledge of the comets, in view of the recently established connection between shooting stars and comets. It is exceedingly desirable that we should know more than two or three hundred out of the many thousands of comets which undoubtedly belong to our system, especially as most of those which we know move in parabolic orbits. Were our knowledge of comets more complete we should surely know more meteor streams and comets belonging one to the other. Mindful of Herr Schumacher’s words “It is natural that astronomers intrusted with the administration of a well-furnished observatory should have no time left for sweeping the sky so minutely and so perseveringly  as is necessary for discovering faint bodies, whilst on the contrary , it seems certain that to the many amateur astronomers who have less extensive means of observation hardly any more useful kind of activity could be recommended”, The Imperial Academy of Sciences at Vienna is induced tom propose for the discovery of comets during the three years from May 31^st 1869 to May 31^st 1872 eight prizes annually . consisting as the receiver may choose of a gold medal or of twenty Austrian ducats representing its value in money.

The award of these prizes will be subject to the following regulations: -

1.      The prize will be given only for the first eight comets discovered in each of the three years named, and only for such comets as are telescopic at the time of discovery, that is invisible to the naked eye. The comet must not have been seen before by another astronomer and must be one whose appearance could ot be predicted with certainty.

2.      The discovery must be communicated immediately and without waiting for further observations, to the Imperial Academy of Sciences, by telegraph if practicable, and otherwise by the earliest post. The Academy undertakes to transmit the news immediately to other observatories.

3.      The time and place of discover with the plan and course of the comet must be given as exactly as possible with the first notice. This first notice is to be supplemented by such later observations as may be made.

4.      If the discovery should be confirmed by other observers, the prize will not be awarded unless the observations of the discoverer suffice for the determination of the orbit.

5.      The prizes will be awarded in the general meeting of the Academy held at the end of May each year. In case the first notice of a discovery arrives between 1^st January and the end of May, the final award of the prize will be deferred till the general meeting in May in the following year.

6.      Application for the prize must be made to the Academy within five months from the time of the arrival of the first notice. Later applications will be considered.

7.      The Imperial Academy will procure the decision of the permanent astronomers of the Observatory at Vienna as to the fulfilment of the conditions in Nos 1,3, and 4

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The Full Strawberry Moon

 The Full Moon on June 11th is called the Strawberry Moon, because this is the time of year when the strawberries, considered the most celebrated and important of the berries, were traditionally harvested. Nowadays we can buy strawberries at any time of year. 

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Walter Gale in Australia observes Jupiter in 1896 with a Cooke telescope

 I am glad to be able to report that observing conditions generally have been very good with us since the beginning of last month, and that at least one other member besides myself has taken advantage of the good seeing to make drawings of Jupiter. I am unfortunately divorced from my observatory for some months, but have with me in the country an excellent 5-in. Cooke altazimuth as well as accurate time.

 

I have never hitherto prosecuted a careful and continuous study of the giant planet's surface, and confess to great surprise at the vast and rapid changes that become apparent. This especially struck me first in the case of the N. equatorial belt, the northern and equatorial components of which exhibited alternately dark masses and condensations, divided by white spots after intervals of only five Jovian rotations. On March 13 and 14 there were typical instances of this.

 

On March 26, 20h 40m, G.M.T., a faint wisp across the equator, was conspicuous, and next night, March 28, 2h 20m G.M.T., was invisible, while the equatorial region near the c.m. showed considerable change. Definition excellent, 4 to 5 on both occasions, power 200. The N. temperate area, however, has puzzled me most, for the three belts often seen have varied much both in visibility and latitude, while with exquisite definition on April 1, at 0h 20m G.M.T., the following portion seemed overlaid with vapour of a sage green tint, and the belts (2) were only faintly visible in their preceding parts,

 

The Red Spot has been well seen on several occasions of almond shape, the f. end slightly more pointed than the p. Its tint seemed uniform, and a very delicate brick red, like a faint stain. It is overlaid on the S. side by the S. temperate belt, which is closely double through nearly its whole extent, and f. from the centre of the Red Spot is much darkened and sinuous. The great spot's preceding end was estimated on c.m. at 1h 15m G.M.T., April 1, and the following end on c.m. at 21h 52m 36s G.M.T. of same date. In the transit of Satellite I. on February 22, observed at Waverley, near Sydney, with my equatorial, the shadow must have been occulted by the satellite, which is perhaps worthy of note.

 

 WALTE R F. GALE .

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A little ramble through Canis Major the Greater Dog

 

Canis Major is a stunning constellation which I am afraid to say we never see at its best from Britain because it is quite low down in the sky. In the Mediterranean area it would be much higher in the sky and would look even more impressive. The constellation which can be seen in the winter months in Britain represents one of the hunting dogs that follow Orion the Hunter across the sky and contains Sirius or the Dog Star the brightest star in the sky.

In classical Greek mythology the constellation was simple known as Canis which represented Laelaps who was a gift from Zeus and was the hound of Acteon who was the son of the priestly herdsman Aristeaus and Autonoe in Boeotia which is part of Greece. From the earliest of times, it has always been the Dog of Orion an image of which Aratos drew in his phainomena.

The Arab astronomers knew Canis Major as Al Kalb al Akbar the Greater Dog, the Arabic astronomer Al Biruni also referred to it as Al Kalb al Jabbar the Dog of the Giant. The Hindu astronomers called it the Deer Slayer, while northern European civilisations called it Greip the Dog of the myth of Sigurd.

As I have already said Sirius the Dog Star which is the brightest star in the sky has at least 50 different names given to it be civilisations around the world, Sirius is sometimes written as Syrius, this version was used as late as the time of Sir John Flamsteed the first astronomer royal in the early 1700s and has often been associated with sparkling or scorching .

Although most ancient civilisations have the constellation connected with a dog to the native aboriginals of Australia it was their Eagle. As Sirius is the brightest star in the sky the Egyptians sometimes associated it with Thoth the god of writing, wisdom and magic. Sirius was also worshipped by the Graeco - Egyptian name of Sothi the Brightly Radiating One and Sothis Fair Star of the Water.

The Phoenicians are said to have known the star Hannabeah, the Barker, Arabic astronomers sometimes called it Suhail which is a general designation for bright stars. However, some Arabic sources give it the name Barakish meaning of a Thousand Colours. This would be due to Sirius being seen low in the sky and light passing through the atmosphere making the star to appear to twinkle a lot, hence appearing to change colours.  In China the astronomers don’t seem to have made so much of Sirius as other people did. It is sometimes mentioned with other stars in Canis Major as Lang Hoo.

Sirius has an association with Egypt in the event known as the Heliacal Rising. This is when Sirius appears in the sky just before sunrise in the morning. Egyptians knew that when this happened the river Nile was about to flood. Farmers had to make sure their fields were ready to be flooded and all the important sediments that would be laid down by the river on the fields hopefully insuring a good crop for the year.

Associated with the Heliacal Rising is a term that will be familiar to everyone, and this is the Dog Days of Summer. We can go back thousands of years to record when the helical rising occurred and was observed, and these dog days can occur between Jul 3^rd and August 10^th depending on when Sirius was first seen.

The brightness of Sirius or its magnitude is -1.4, in astronomy the lower the number the brighter the star. I know this seems strange but that is the way the brightness of stars is worked out. Stars like Sirius which have minus numbers are the very brightest. The brightness of Sirius is because it is astronomically speaking very close to us being only 8.4 light years away. Sirius is an A class star it is hotter than the Sun.

 Sirius is a double star its companion is a white dwarf star. In fact, the white dwarf orbiting Sirius was the first star of its kind to be discovered. It was purely by chance when the American telescope maker Alvan Clark was testing a new telescope on January 31^st, 1862, that the companion was discovered. At first it was not realised how important a discovery it would be, leading to a whole new area of astronomical research into white dwarf stars.  A telescope is needed to see the companion star.

As Sirius is the Dog Star and the brighter of the two stars it is known as Sirius A the companion is known officially as Sirius B. However, because Sirius is the dog star the companion is known unofficially as the Pup.

White dwarfs are very old stars that have lived out most of their lives. Our Sun will end up as white dwarf star in a few billion years’ time. White dwarfs are stars that have all the gas inside them massively compressed. This material is known as degenerate material. A tablespoon of material would weigh many tons.

The second brightest star in Canis Major is not beta but the star epsilon which is the 5^th letter of the Greek alphabet. I have mentioned before that in 1603 the German astronomer Johann Bayer introduced a system whereby the 24 brightest stars in a constellation were allocated a letter from the Greek alphabet, alpha being the brightest, then followed by beta through to the last letter of the Greek alphabet omega. Here we have another example where the system does not work. Epsilon whose name is Adhara which means Virgins.

Adhara has a magnitude of 1.5 it’s a B class giant star with a massive surface temperature of around 22,500 degrees compared to our Sun’s temperature of 5,800 degrees. It lies at about 400 light years and will probably end its life in a supernova explosion and destroy itself.

Next in brightness is delta or Wezen which is the modern-day version of Al Wazn which means Weight. Remember most of the star names we use today are Arabic. Wezen is an F class supergiant star with a magnitude of 1.8 and is about 1,600 light years away, it is hotter than the Sun. 

Beta or Mirzam which means the Announcer is to the right of Sirius, the star marks the right fore foot of the dog. The Chinese call it Juen She or the Soldier’s Market. It is a magnitude 1.9 star making it the third brightest star in Canis Major. It lies around 490 light years away and is a B class giant star with a surface temperature of around 24,500 degrees, yet another supernova candidate for the future.

Below Wezen and to the left is eta whose name is Aludra; the meaning of the name is unknown. Its magnitude in 2.4 and it’s a B class supergiant with a hot surface temperature of 15,500 degrees and is about 2,000 light years away. This is probably yet another candidate for a supernova in the future.

A line drawn from epsilon or Adhara will lead to zeta or to give it its Arabic name Al Furud which means The Bright Single One. As the star has a magnitude of 3.0 its clearly not the brightest star in Canis Major so its name night seems a little surprising. The Arabic astronomer Al Sufi whose name will be known by some due to his star catalogue called the star Al Agribah which means the Ravens. Whichever name we use zeta is 362 light years away and is another hot B class star with a surface temperature of about 18,000 degrees.

Canis Major contains several star clusters yet surprisingly only one messier object. This is Messier 41. It was first seen by the Italian astronomer Giovanni Battista Hodierna 1597-1660 in 1654, although there are reports that suggest it might have been seen by Aristotle around 325 BCE. This is quite possible because under good clear conditions it can be seen with the naked eye as M41 has a magnitude of 4.5.

M41 is an open cluster which contains about 100 stars and is sometimes referred to as the Little Beehive Cluster. The cluster is around 2,300 light years away and as it is an open cluster it is relatively young being only about 190 million years old.

Some of the other star clusters in Canis Major include NGC 2360 an open cluster which is known as Caroline’s Cluster after its discoverer Caroline Herschel, Caroline discovered the cluster in 1783. She was the sister of William Herschel who discovered the planet Uranus in 1781. With a magnitude of 7.2 a good pair of binoculars or a small telescope is needed to see it. NGC 2360 is about 3,700 light years from Earth.

Close to NGC 2360 is NGC 2359 known as the Thor’s Hemet Cluster. It is 11,960 light years away and with a magnitude of 10 a telescope is needed to see it. At the centre of the cluster is a Wolf Rayer star, this is an extremely hot star which astronomers believe is going through a period of its evolution before it goes supernova.

NGC 2362 another open cluster first seen by the Italian astronomer Giovanni Hodierna in 1654 has a magnitude 6.0 meaning a pair of binoculars are needed to find it. William Herschel described it as a beautiful cluster.

I will finish my tour of Canis Major with NGC 2207 which is a galaxy about 81 million light years away. It is a spiral galaxy and is in the process of crashing into another galaxy known as IC2163. The IC or Index Catalogue was introduced in 1895 as a supplement to the NGC or New General Catalogue that was introduced in 1888.

NGC 2207 is a good hunting ground for supernova hunters in NGC 2207 there have been 5 supernovae seen in recent years, these being in 1975,1999, 2003, 2013 and 2019.

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