Solar Viewing at Brecon on 22nd June

On Saturday, 22nd June 2019 from 10.00 a.m to 4.00 p.m. CAS will be running another solar observing session which is set to tie in with the 2019 summer solstice on Friday, 21st June.

Using specialist Society equipment you can join fellow members in looking (subject to the weather, of course) SAFELY at our nearest star - all life on Earth depends on it! Experienced CAS astronomers will be on hand to help you get started in this fascinating subject and enthral you with all things solar!

Celebrate the summer solstice in one of Wales's beautiful National Parks. Go to: The National Park Visitor Centre, Libanus, Brecon LD3 8ER (telephone 01874 623366). Please note that, unless you are one of the helpers in the CAS outreach team, car parking charges will apply.

Events to celebrate the 50th anniversary of the Apollo 11 Moon landing

There is a vast range of events occurring across the world to celebrate the 50th anniversary of the landing on the Moon of Eagle, Apollo 11's lunar module, and Neil Armstrong becoming the first person to step onto the lunar surface on 21st July 1969. CAS has therefore created for members' use a timetable of key events and other activities.

Hints on photographing the Moon! -------------------------------------------

Catch the very latest astronomy news from ---------------

Day-by-day guide to this month's night sky ---------------------------------

Space-themed Music at St David's Hall on 25th June

The Society will have a stand at St David's Hall for the performance of Gustav Holst's "The Planets" suite by the Philharmonia Orchestra, starting at 7.30 p.m. on Tuesday, 25th June.

The stand will provide some background interest and expertise for the audience. It will consist of general astronomical information for those who need help getting started, some telescopes/binoculars on display and advice from experienced astronomers. People can come into the Hall and see us without going into the concert - we'll be on the small stage on Level 3 near the bar!

Please click here for further information about the other musical performances on the evening and to make bookings at St David's Hall.

New SpaceX Satellites are of Major Concern to Astronomers

Many CAS members may have recently seen a new phenomenon in the night sky: the 60 satellites that were launched from Cape Canaveral, Florida on 23rd May and are the first build-out of Elon Musk's Starlink internet constellation. Eventually, the plan is for this telecommunications system to provide low-cost broadband internet access to paying customers around the planet, including remote areas where internet service is hard to come by. Click the button opposite for more information.

Society Help for Schools etc

As shown here, Cardiff Astronomical Society welcomes all invitations from organisations such as colleges, schools and guide/scout/brownie groups located in Cardiff and surrounding areas for an outreach stargazing/astronomical event for all ages and levels of knowledge. Society members very much enjoy bringing our passion for the subject to a wider audience and helping everyone to get started in this fascinating subject. We do not charge a fee for our expertise and participation; the enjoyment is enough reward and we will do our very best to ensure a worthwhile and enthralling evening. We would, however, be grateful for reimbursement of travelling expenses and petrol costs to venues outside of Cardiff and its environs. Otherwise the cost would fall on individuals and the non-profit-making Society.

It should be noted that CAS has a formal Policy on Child Protection and the Protection of Vulnerable Adults which is accessible via this link CAS Child Protection Policy

Gift Aid

CAS is registered for Gift Aid. This means that, if you are a UK taxpayer, we can claim back the standard rate tax on subscriptions (and on any donations) paid since the Society became a registered charity on 31st October 2016 (giving an effective 25% boost to the amount the Society has received). However, in order to reclaim these monies from HMRC, we need all members who pay tax to complete and sign a Gift Aid Declaration form. Please note that if you have paid your subscriptions by PayPal, you will have already been asked if you would consent to those subscriptions being Gift Aided - but we still need a completed and signed Gift Aid Declaration form in order for us to reclaim the tax paid as Gift Aid.

If you are eligible, please take a form (using the button opposite) and then complete & sign it and pass it to us at one of the fortnightly talks or send it to CAS by post or email (see the bottom of the form). Thank you for your help!



The Cardiff Astronomical Society (CAS) is a thriving society located in South East Wales. It has been in existence for over 40 years and is one of the largest amateur astronomical societies in the UK. CAS continues to provide a range of facilities for both Society members and the public at large including a varied programme of talks on Thursday evenings (except in August) at the Physics and Astronomy Department of Cardiff University. In addition, regular night sky (and occasional solar) observing sessions are held at the Society's own Observatory at Dyffryn Gardens.

Our members come from all walks of life and their knowledge of astronomy ranges from complete beginner to advanced. You don't need any specialist knowledge to join us and neither do you need to own a telescope or binoculars. It's also possible to try us out before joining!

More details about the Society and what it does are available here

We are keen to get more Society members on board to assist with the running of CAS events - please see here how you can Help Us

>Next Talk

Thursday, 27th June 2019 at 7.30 p.m. "Was Einstein 100% right about Relativity?" to be given by Professor Malcolm A H MacCallum, Queen Mary University of London. Our talks - which finish no later than 9.30 p.m. - are usually held in Room T2.09 (the Trevithick Lecture Theatre) at the School of Physics and Astronomy, Cardiff University, The Queen's Buildings, The Parade, Cardiff CF24 3AA - please click here

Malcolm MacCallum is an Emeritus professor at Queen Mary University of London, where he is a former Vice-Principal. He has also worked at universities in Australia, France, Italy, Germany and the USA, and at King's College Cambridge, and been Director of the Heilbronn Institute in Bristol. His research interests cover all aspects of non-Newtonian gravity including cosmology, black holes and gravitational waves. In 2010-13 he was President of the International Society on General Relativity and Gravitation.

The talk will briefly introduce the special and general relativity theories. Special relativity is very well tested. For more than 50 years the evidence for general relativity rested on the "classical tests". Then more sophisticated solar system tests and the first strong field tests, from the binary pulsar, were made. Very recent results about black holes give extra confirmation. There are still anomalies in data, and good theoretical reasons for seeking a new theory.

>Next Observing Session

Friday, 6th September or Saturday, 7th September 2019 from 8.30 p.m. until midnight at Dyffryn Gardens. Further details are available here

>Next Star Party

Friday, 27th September 2019 from 7.30 p.m. until 9.30 p.m at Dyffryn Gardens - please click here

Please note that the Society generally does not hold star parties during the summer months. This is of course because the night skies do not start to get dark until it is quite late which would mean that a star party (usually lasting for about two hours) would finish after 11.00 p.m.


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Come and join some of the Society's 275 members at one of our talks or observing events. We promise a warm and friendly welcome for all. Only £15.00 per annum also means you can make use of our Library