Alan Willison, chairman of Hertford Astronomy Group, continues his beginners' guide to astronomy.

 

As the Earth continues its journey around the Sun we start to look at another part of the sky and the constellations that we have enjoyed throughout the winter start to disappear over the western horizon.

We still have a few weeks left to say farewell to Orion the Hunter with its myriad of interesting items.

Leo the Lion is now the major constellation to fill the sky in the southern direction. Leo is a large constellation and is one of the zodiacal constellations. These are the ones that you see in horoscopes and hence it might seem a familiar name to you.

Leo has a distinguishing pattern with its head looking like a backward question mark. This is also known as the Sickle after the hand tool that was used to cut the wheat.

At the bottom of the question mark is the bright star Regulus. Regulus is number 21 in the chart of brightest stars in the sky, so if you can see more than 21 stars then you will know that you should be able to find Regulus.

Regulus is actually a 4-star system, but you would be very pressed to be able to see the other three companions even with a large telescope.

Regulus is 79 light years away from Earth. That means that if you could travel at the speed of light it would take 79 years to get there. If you were looking at the Earth from Regulus then the Second World War was in full swing.

 

READ MORE

 

There were 13 names in the original Zodiac, but it was felt that it was neater to have 12 as that was a better mathematical number to work with. The constellation Ophiucus, the serpent bearer, got dropped from the list. He still exists in the stars and has an interesting tale to tell but not on this occasion.

As mentioned, the Zodiac is familiar through horoscopes. Horoscopes are a part of astrology which was very closely linked to astronomy in the past.

Johannes Kepler, famous for calculating the orbits of planets in the 16th century, also created horoscopes (or prognostications). As part of his duties as district mathematician to Graz in Austria, Kepler issued a prognostication for 1595 in which he forecast a peasant uprising, Turkish invasion and bitter cold, all of which happened and brought him renown.

When we study astronomy we talk a lot about what we can see towards the south. The reason for this is that the southern horizon is like a changing picture show.

As the year progresses we see new things appearing but what about the north – is there nothing to see there? Due to the Earth’s tilting axis there are lots of things to observe and the great thing is that many of them are there all year.

They certainly change their orientation but appear to revolve around one star – Polaris. These constellations are known as circumpolar as they appear to revolve around the Polaris.

Polaris is also known as the Pole Star or North Star because it lies (almost) exactly over the North Pole.

That being the case, it was a very important star to know if you were to use it to aid navigation at sea as it was there long before sat nav became the norm. Being such an important star, it is often a disappointment when it is pointed out to new observers.

It isn’t particularly bright, featuring at number 48 on our list of bright stars. It is though a triple star system with three stars all connected to each other by gravity.

Another circumpolar constellation is Cassiopeia whose nasty behaviour towards her daughter Andromeda was the subject of last month’s issue. However, the constellation of Cassiopeia also hosts a fantastic sight – the Ghost Nebula.

You only have to look at Martin’s fabulous photo to see why it is called that.

Welwyn Hatfield Times: Ghost NebulaGhost Nebula (Image: Martin Weston)

This nebula in the constellation of Cassiopeia has flowing veils of gas and dust that have earned it the nickname "Ghost Nebula". Officially known as IC 63, this nebula is located 550 light years away in the constellation Cassiopeia the Queen.

The brightest stars embedded in nebulae throughout our galaxy pour out a torrent of radiation that eats into vast clouds of hydrogen gas – the raw material for building new stars.

This etching process sculpts a fantasy landscape where human imagination can see all kinds of shapes and figures.

Going back to our northern looking sky, there is a little known constellation beneath the handle of the Plough called Canes Venatici – the Hunting Dogs. It is only two stars joined together with an imaginary line (and a lot of imagination to see any dogs).

The explanation that this was a case of mistaken identity over the words being translated and that it should have been called the Staff makes a bit more sense.

Anyway, in this constellation lies another spectacular sight – the Whirlpool Galaxy. This has been chosen as photo of the month (pictured below) because of the explanation of the amount of work that had to go into capturing this image.

If you are intrigued by the image, and want to understand all those terms and numbers, then consider becoming a member of the Hertford Astronomy Group where you talk to the people who took the photos.

The next meeting of the group is to be held in the Lindop Building at the University of Hertfordshire, College Road, Hatfield on March 8 at 8pm.

It will be an exciting talk about how planets form from dust given by Professor Cathie Clarke.

Another event that you might be interested in is a hands-on session called 'My Telescope Doesn’t Work!'. Here we will be able to help you to get your telescope doing the job it is meant to do.

This is to be held at Bramfield Village Hall, Bury Lane, Hertford, SG14 2QL on Saturday, March 25, from 7pm to 10pm, and is free to attend.

Just let us know using the form on the website - https://hertsastro.org.uk

Don’t forget to bring your telescope along.

 

Photo of the Month

Welwyn Hatfield Times: Whirlpool GalaxyWhirlpool Galaxy (Image: Kevan Noble)

At 30 million light years distant and 60,000 light years across, also called M51 or NGC 5194, is one of the brightest and most picturesque galaxies in the sky.

Anyone with a good pair of binoculars can see this Whirlpool near the constellation of Canes Venatici.

Astronomers speculate that M51's spiral structure is primarily due to its gravitational interaction with a smaller, nearby companion galaxy, NGC 5195, just off the top of this image.

The companion's gravitational influence is triggering star formation in the Whirlpool, as seen by the numerous clusters of bright young stars, highlighted in red.

All seven filters for this one, all at 120s: L = 40; R = 40; G = 40; B = 40; H = 25; S = 50; O = 65.

10 hours total; Astromiks 36mm SHO 6nm Filters; 30 x Darks, Flats (for each filter) and Bias; ZWO ASI294MM Pro 120 gain, -10C; ZWO 7x36mm EFW; ZWO EAF; Stellalyra 8” Ritchey-Chrétien Carbon; HEQ6; ASIAIR Plus; Astro Pixel Processor; Pixinsight; Photoshop 2022. Image: Kevan Noble.

 

                                                                                                                                

Get more stories like this delivered to your inbox every week by signing up to the Welwyn Hatfield Times In Brief newsletter.