Welcome to CAS

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The Chesterfield Barnett Observatory

Our observatory is open every Friday from 8pm onwards until the last person leaves. We always give visitors a warm welcome so if you'd like to join us, please feel free to do so. You don't need to book your visit, just pop over to see us and we'll show you around and make sure you get the opportunity to do some stargazing too if the weather is with us. We rely on the generosity of the local community to keep the observatory open so please can you place a small donation of £2 in our visitors' pot when you visit.

Friday night is also members’ night and whilst we are always delighted to receive visitors please be aware that sometimes our members could be busy with their hobby which can require a high level of concentration so might appreciate it if you avoid interrupting them when using or setting up a telescope. Thanks for your understanding.

If you'd like to learn more about the observatory, click on the menu item 'Our Observatory' at the top of this page.

We very much hope that you will come and visit us on a Friday evening when we will make sure you have an astronomically good time 🙂

Address : Hastings Close, Newbold, Chesterfield, S41 8RH

Tel: 0751 751 0083

Please go to the bottom of this page for a map showing the location of the observatory

The Future of the Milky Way

On Friday 7th April we were treated to a highly entertaining talk on one potential future of the universe by James Mullaney from Sheffield University. The model James took us through showed very little change in the next few hundred million years. In about a billion years' time the Sun will be too hot for life to exist on Earth.

The Sun will eventually run out of fuel in about 5 billion years' time and then it will collapse in on itself and become a white dwarf. Shortly afterwards the Andromeda galaxy and the Milky Way will merge making a massive galaxy with between 6 and 8 hundred billion stars in it.

If the current expansion of the universe continues as expected, which is dependent upon an assumed effect of dark energy, then in many trillions of years' time all matter will convert into photons. We will of course watch the universe and report back regularly every few trillion years to see if the model is accurate!

Our thanks to James for his time and for a very interesting talk that prompted lots of questions.

Mapping the Milky Way


On Friday 17th February we received an excellent talk from Professor Rob Jeffries from Keele University all about the latest ESA space telescope, Gaia.

Gaia is a twin-telescope that will map, catalogue, size and age many stars. The baseline number of stars it will map is 1 billion all of a magnitude of 20 or greater representing around 1% of all the stars in the Milky Way.

Gaia will be working for 5 years and our first significant cut of data will be received in April 2018. It is located at Lagrange point L2 a million miles away from the Earth where it is in a very stable orbit.

Some of the key objectives of the project will be:

  • To produce a stereoscopic (3D) map of the Milky Way
  • To more accurately map out the distance to many stars
  • To more accurately determine the age of many stars
  • To identify thousands of asteroids and comets not seen previously
  • Identify new exoplanets
  • Discover new quasars

Gaia is set to boost our understanding of the Milky Way by such an extent that it should revolutionise astronomy.

If you would like to learn more about the Gaia mission, there’s an app you can get to keep you up to date on your phone:


And you can learn more about this amazing project at:




Our thanks to Rob who we hope will come back and update us in the future as Gaia unfolds some of the secrets of the Milky Way.

Thanks also to Marilyn for organising this.

Neutrino Talk - 27th January


On Friday 27th January we were treated to a talk by Jost Migenda of Sheffeld University, a PHD student of Dr Matthew Malek pictured above.

His talk entitled The Death of a Star: Observing Supernovae with Neutrinos was both interesting and amusing.

He explained Neutrinos are ghost-like particles that can literally “go through walls”. He had us laughing at his graphics from a Harry Potter film of a ghost scene.

He first gave us a brief but exciting history of neutrinos, describing how they can be used to look inside a supernova in the moment of explosion and what we might learn from this.  What fascinated me was the amount of time it took from a star losing its fuel to falling in under its own gravity - milliseconds.  When the heavy elements have fallen into the core of the star and compressed to when it explodes - 10 seconds.

Fascinating to  think it takes billions of years for a star to come to life, but its death occurs almost in an instant.  Of course the shockwave that comes afterwards initiates star formation in other interstellar clouds.  Thus we are recycled!!

He outlined what has already been achieved in neutrino detection and told us of a new detector to be built in Japan starting next year.  He is hoping that Betelgeuse will wait until the detector is ready in 2024 before it goes supernova.  I personally hope it will happen in my lifetime!!!


CAS Secretary

Our Christmas Party

22 members attended the annual party on Friday the 6th January.  There were crosswords on Astronomy and the traditional quiz compiled by Jim Fisher.  This year he was unable to attend as he was visiting family in New Zealand.  He had sent me the quiz which was a mixture of astronomical and general knowledge questions.

We divided into teams and began.  Some of the questions started discussions as to the interpretation and I asked members to refer queries to Jim!!  When it came to the answers there was more fun from members not agreeing with the answers - with good reason.  We have now established that Neil Armstrong and co landed on the moon on the 20th July 1969 but did not step onto the surface until the next day!!!  Thanks to Peter Davison as it was his birthday the day they landed so he should know.

There had to be a tie break as two teams finished with 17 and a half points.  The winning team as seen below when I presented them with the cup.


Out of the archives I had produced a quiz from 1992 - again one of Jim's.  This caused some discussion even from those of us who were old enough to remember life then.  The question causing most hair pulling, was 7 =  S on a F P P­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­­.  OK if you want to be argumentative you can say 5 but you will have forgotten the front and back!!

This year we did not have loads of food left and members were good enough to take their own food home if it was left over.  We had a box of biscuits given to us by Maureen Jenkinson and these with other boxes of biscuits will keep us going for many a Friday to come.

I hope you all had a good time and I wish you a healthy and prosperous year to come.

Marilyn Bentley


January 2017

Darkness visible:  The Hunt for the Missing Matter


On the 2nd of December we were once again treated to a talk by Dr Matthew Malek.

Although we had previously had a talk on Dark Matter it was interesting to get Dr Malek's take on things.  He did not disappoint.  His talk was full of humour and his presentation clear and precise.

He told us  "The 'Mystery of the Missing Mass' has been vexing astronomers and physicists for over eighty years. It all began in 1933, when Swiss astronomer Fritz Zwicky's observations of galactic clusters led him to postulate the existence of a 'dark matter'.  Since then, an ever-growing body of evidence supports the conclusion that over 80% of the mass of the Universe is undetectable by normal means.  We now know that dark matter exists, but what is it?  How was it formed? Why is it so hard to detect?"

In his talk, he reviewed the cutting edge experiments that are looking for dark matter right here on Earth, and what the prospects for discovery are in the next decade.  They are tantalizingly close.  He promised to revisit us with any progress in the future.

He was regaled with questions and said afterwards that he had enjoyed the exchange.  We kept him very late and when I emailed him the next day I apologised for this as well as thanking him for a very enjoyable talk.  He replied it was always fun coming to CAS.

Although we have had all three talks Dr Malek delivers, I am pleased to tell you that he is putting together a talk especially for us and will visit us next year.  Watch this space.

Article by Marilyn Bentley

Open Evening Saturday 8th October 2016

Despite the poor weather we had lots of visitors to whom we are very grateful. We hope that everyone enjoyed themselves and that we wil see you again soon.

How to Build a Universe - 7th October

A fascinating talk explaining how the universe was created was given by Dr Stuart Muldrew of Leicester University at the observatory on the 7th October.

Our secretary, Marilyn has written the summary below of this excellent talk.

Dr Muldrew gave us an informative talk on his work modelling the universe.  He told us observations of galaxies are constantly pressing to new depths, giving us a series of snapshots in time after the Big Bang.  Ideally we want to understand how galaxies evolve, linking the observed snapshots to produce a galaxy family album.

To astronomers, computers are becoming equally as important as telescopes in explaining the Universe in which we live.  Building computer models of how the Universe evolves allows us to explain evolution between the different types of galaxies that we observe.  He showed us current predictive computer models and compared these with the actual data.  They were strikingly similar.

He told us of the key ingredients that go into building a computer model of the Universe.  He then used this to explain how galaxies trace the underlying dark matter distribution, and are affected by the energy released from their supermassive black holes and internal supernovae.

The talk generated many questions from members and Dr Muldrew commented afterwards that he had enjoyed the exchange.  We took him into the Dome and Sue gave him a potted history of our telescope and he was very impressed.

Our thanks to Stuart for his time and his excellent talk in which he conveyed complex concepts in a very clear manner.


Talk on the 16th September

Unfortunately the talk entitled 'Is there life out there?' due this Friday at the observatory has been cancelled. Instead there will be a talk introducing newcomers to atronomy. The talk will start at approximately 8.15 and should last around one hour.

We apologise for the change but hope you will attend and enjoy the alternative talk.

Gravitational Waves Talk by Ed Daw

Friday the 5th of August saw Ed Daw of Sheffield University give us a talk on the FIRST DIRECT DETECTIONS OF GRAVITATIONAL WAVES BY LIGO. (Laser Interferometer Gravitational-wave Observatory)

 He has been working on the project for 19 years and told us of the difficulties of building the detector.  Even getting it straight on the curved surface of the Earth was a problem.  They even had to compensate for the pull of the Moon's gravity!

He made the story funny and even made the maths humorous. They even had to contend with crocodiles in the water filled channels which run down the sides of the concrete tubes housing the detector, which can be seen in the above image.

When the LIGO experiment, conceived in 1972 by Rai Weiss at MIT, had successfully detected gravitational waves from binary black hole collisions approximately 100 million light years away, it was met with apprehension.  The first wave came through on the 14th September 2015.  They spent weeks checking whether it was really the gravitational wave or a misinterpretation of the data.  Ed said the hardest part was not being able to say anything until the official announcement was made in February of this year.

The second wave to come through again took everybody by surprise.  It was on Boxing Day and at the time Ed was caving and didn't know until he surfaced and read his emails later.  This time they knew what they were looking for.

Ed is obviously very enthusiastic about his work and this shone through in his talk.  He enjoyed the questions and was surrounded after the talk by members wanting to know more.  He was very complimentary about our telescope calling it "some feat of engineering".

You can learn more about LIGO at this website:


Our thanks to Ed for giving such an entertaining talk about this amazing project.

CAS visitor Ed Daw 7152

Ed Daw at the Chesterfield Observatory

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