We are back at our normal venue from 3rd Sept. 2021 |
This page lists our monthly meetings. For other events open to the general public, see our Events page
Dates are set well in advance but the 'content' of the meeting is only updated (from our 'meetings database') when details are entered, so 'blank' or 'TBA' may be shown when data has not yet been entered (please be assured that the meeting will take place and a talk on (some) Subject will be delivered by (some) Speaker ! )
During the COVID-19 restrictions, all meetings are being held on-line using ZOOM. Meetings are normally held at the Church Hall (aka 'The Soltau Center') of St James-the-Less, Stubbings, Maidenhead SL6 6QW, from 7.30 (for a ZOOM link, or map and directions, see the About MAS (Where we meet) page
The Main Topic is usually delivered by an invited guest speaker. We aim to provide a diverse range of subjects linked (in some way) to Astronomy - whilst the 'Second Session' is typically delivered by one of our members. If time allows, the evening concludes with a short 'What to see this month'.
Details of a typical evening (times are approximate) :- 7.30pm. The evening starts with the Chairman delivering any important Announcements and then introducing the main speaker. 7.45pm (latest). Main Topic Speaker gets up and the lights are turned off. If you arrive after 7.45, please enter the Hall by the first door (on the right, after the entrance) and please be extra careful when finding a seat at the back of the Hall as members often setup telescopes there ! 8.45-9pm +. Coffee break during which visitors often chat with members who have set-up their telescopes at the back of the hall. If the weather is good, sometimes members will nip out for a quick look at the sky. Smoking is permitted outside the Hall, however smokers are asked to avoid any 'observers' (smoke particles always seem to get into optical equipment, no matter how well 'sealed' it may be) 9.15pm (at the latest). The 'Second Session' then runs for about 45 mins, typically ending with "What's Up !" (what to look out for in the sky this month) 10pm. We aim to clear the hall by 10pm. Post meeting Observing. If the weather is good, the Observing Organiser then leads the way to our chosen observing site, or (if the weather looks even a slight bit 'iffy) members sneak off to the local Pub instead :-)
Next meeting :
(+) 7 Jun 2024 MAS 67th AGM - (Annual General Meeting)
Meetings Archive |
The meetings archive gives an 'overview' of the Society activities over the past 10 years (see also the Events page).
Members have access to the full 'History of MAS' (including AGM minutes going back to 1957) along with full names and photos
The MAS 'year' runs from September of one year to June of the following. The end of year AGM in June elects the Committee for the following year (there are no meetings in July and August - although often members will meet informally at the local pub - which gives the new Committee time to 'get a grip' on running the Society)
The "short cuts" (in the 'title bar', at the very top of this page) will take you to the June AGM entry for the end of that MAS year
The Maidenhead Astronomical Society meetings archive (last 10 years only)
Missed a meeting, or can't remember when a topic was last covered ? Here is the archive of past MAS meetings.
Note that this list covers only our monthly meetings and AGM's. Reports on Observing and Other Events are separate pages
If notes were taken at the meeting, the date below is underlined and shown with a '(+)' = click to see the notes (if no '(+)' is shown, no notes were taken - or, more likely, the webmaster hasn't found them and posted them up yet :-) )
(+) 3 May 2024 The Exploration of Venus - (Jim House)
(+) 5 Apr 2024 The Visible Universe - (Doctor Max Whitby)
(+) 1 Mar 2024 Water in the Universe - (Prof Jonathan Tennyson)
(+) 2 Feb 2024 The Mechanics of Eclipses - (Sheridan Williams FRAS)
(+) 5 Jan 2024 Telescope Parade - (and the Parker Solar Probe by Arthur White)
(+) 1 Dec 2023 SPECIAL FEATURE Herschels Lunatick Friends - (Andrew Lound)
(+) 3 Nov 2023 Binary Pulsars Einsteins Perfect Laboratories - (Barry Kellett)
(+) 6 Oct 2023 Solar Space Weather SOHO - (Dr Eric Dunford)
(+) 1 Sep 2023 The Changing Climate of Mars - (Peter Read)
(+) 2 Jun 2023 MAS 66th AGM - (Annual General Meeting)
(+) 5 May 2023 Two talks by members - (LATE CHANGE)
(+) 31 Mar 2023 Overview of telescopes and mounts - (Dave Hayes)
(+) 3 Mar 2023 Study of our Galaxy in the Era of Gaia - (James Binney)
(+) 3 Feb 2023 The Galaxy without a dark side - (Barry Kellett)
(+) 6 Jan 2023 Telescope Parade and Workshop - (by members)
(+) 2 Dec 2022 Xmas Social Photo Comp and Quiz - (set by members)
(+) 4 Nov 2022 Exploration of Jupiter - (Dr Mike Legett)
(+) 7 Oct 2022 The Lunar 100 - (Dr Lilian Hobbs)
(+) 2 Sep 2022 InfraRed Astronomy - (Dr Eric Dunford)
(+) 10 Jun 2022 MAS 65th AGM - (NOTE 2nd Friday)
(+) 6 May 2022 Gravitational Waves - (Joshua Pooley)
(+) 1 Apr 2022 Saturn - (Michael Foulkes)
(+) 4 Mar 2022 Update on the Exploration of Mars - (Jim House)
(+) 4 Feb 2022 What Astronomy Tells Us About The Origins of Life On Earth ? - (James Hough)
(+) 7 Jan 2022 Telescope Parade and Workshop - (by Members)
(+) 3 Dec 2021 Christmas Quiz set by members - (followed by Social Evening)
(+) 5 Nov 2021 CANCELLED - (Hall closed)
(+) 1 Oct 2021 Dark Nebulae - (Owen Brazell)
(+) 3 Sep 2021 How we reached the Moon - (Jerry Stone)
(+) 4 Jun 2021 63rd AGM (ZOOM on line meeting)
(+) 7 May 2021 Milestones in Astronomy - (Rod Hine (ZOOM on line meeting))
(+) 2 Apr 2021 The Red Sun - (Lyn Smith (ZOOM on line meeting))
(+) 5 Mar 2021 Tour of the Universe - (Jane Green (ZOOM on line meeting))
(+) 5 Feb 2021 Space Vehicles - (Graham Bryant (ZOOM on line meeting))
(+) 8 Jan 2021 The Astronomer's Toolkit - (Dr Lee Anne Willson (ZOOM on line meeting))
(+) 4 Dec 2020 Xmas Quiz - (set by members (ZOOM on line meeting))
(+) 6 Nov 2020 The Monster in the Crab - (Gary Poyner (ZOOM on line meeting))
(+) 2 Oct 2020 Is there anyone out there ? - (Bob Mizon (ZOOM on line meeting))
(+) 4 Sep 2020 Two eyes are better than one - (Stephen Tonkin (ZOOM on line meeting))
(+) 5 Jun 2020 COVID19 Postponed MAS 62nd AGM
(+) 1 May 2020 COVID19 Postponed The Monster in the Crab - (Gary Poyner)
(+) 3 Apr 2020 COVID19 meeting CANCELLED
(+) 6 Mar 2020 Recent Developments in Gravity Wave Research - (Martin Dyer)
(+) 7 Feb 2020 Ask an expert Q and A panel - (By Members)
(+) 3 Jan 2020 Equipment Parade - (By members)
(+) 6 Dec 2019 Xmas Quiz and social - (By members)
(+) 1 Nov 2019 The Origin of the Solar System - (James Fradgley)
(+) 4 Oct 2019 Kew Observatory and the origins of modern solar physics - (Dr Lee Macdonald)
(+) 6 Sep 2019 History of Mars Exploration - (Jim House)
(+) Aug 2019 Summer break - (no meeting)
(+) Jul 2019 Summer break - (no meeting)
(+) 7 Jun 2019 MAS 61st AGM - (and Photo Competition prizes)
(+) 3 May 2019 13 Journeys in Space and Time - (Colin Stuart)
(+) 5 Apr 2019 Space Weather - (Dr Colin Forsyth)
(+) 1 Mar 2019 The Extremely Large Telescope (ELT) - (Dr Aprajita Verma)
(+) 1 Feb 2019 Ask the Expert - (members panel)
(+) 4 Jan 2019 Equipment exhibition - (and EGM)
(+) 7 Dec 2018 Christmas Quiz and Social
(+) 2 Nov 2018 Short talks - (by members)
(+) 5 Oct 2018 The Future is out of this World - ( Dr Stuart Eves FRAS)
(+) 7 Sep 2018 13 Journeys through space and Time - (Postponed new date TBA)
(+) Aug 2018 Summer break - (no meeting)
(+) Jul 2018 Summer break - (no meeting)
(+) 1 Jun 2018 MAS 61st AGM - (and Photo Competition prizes)
(+) 4 May 2018 Using Video and an Aurora Encounter - (by members)
(+) 6 Apr 2018 Berkshire Astronomers - (Kenelm England FRAS)
(+) 16 Mar 2018 NEW DATE Jupiter and the Juno Mission - (Dr John Rogers)
(+) 2 Feb 2018 Talks by Members
(+) 5 Jan 2018 Telescope and Equipment workshop - (Q and A with members)
(+) 1 Dec 2017 Xmas Quiz and Social - (Quiz Master Tim H)
(+) 3 Nov 2017 Wonders of the Deep Sky - (Callum Potter)
(+) 6 Oct 2017 Observing the Sun - (by MAS members)
(+) 1 Sep 2017 Gravity Waves - (a recap by Martin Dyer)
(+) 2 Jun 2017 MAS 60th AGM - (and Photo Competition prizes)
(+) 5 May 2017 Novae - (Jim H)
(+) 7 Apr 2017 Comets - (Kenelm England)
(+) 3 Mar 2017 Pseudoastronomy - (Stephen Tonkin)
(+) 3 Feb 2017 Members short stories
(+) 6 Jan 2017 Telescope Parade - (exhibition by members)
(+) 9 Dec 2016 (note 2nd Friday) Christmas Quiz - (and members shorts)
(+) 4 Nov 2016 Observing Planetary Nebulae - (Owen Brazell)
(+) 7 Oct 2016 Astro tourism - (David Phillips)
(+) 2 Sep 2016 Rosetta Space Mission - (Andrew Morse)
(+) 3 Jun 2016 MAS 59th AGM - (and Photo competition results)
(+) 6 May 2016 Build a recording spectrometer John Paraskeva - (2nd half Spectrometer results Alun Halsey)
(+) 1 Apr 2016 The Universe in multiple wavelengths - (2nd half Gravity Waves)
(+) 4 Mar 2016 Astronomy and the Weather - (Robin Oldman)
(+) 5 Feb 2016 Sungrazing Comets - (Kenelm England FRAS)
(+) 8 Jan 2016 (note 8th as 1st is New Year) Practical Astrophotography - (and Telescope Parade)
(+) 11 Dec 2015 Xmas Quiz and members shorts - (NOTE DATE CHANGE)
(+) 6 Nov 2015 The Big Bang Theory - (Kevin Pretorius)
(+) 2 Oct 2015 Starting Astrophotography - (short talks by members)
(+) 4 Sep 2015 Basketballs and Beyond - (Jane Green)
(+) 5 Jun 2015 agm
(+) 8 May 2015 (NOTE 2nd Friday) Talks by Members
(+) 10 Apr 2015 (2nd Friday) planned meeting replaced by - (talks from members)
(+) 6 Mar 2015 Astronomy in Namibia - (Scott Marley)
(+) 6 Feb 2015 Did the Moon sink the Titanic ? - (Dr Barry Kellett)
(+) 7 Nov 2014 Guest stars ancient and modern - (Guy Hurst)
(-) 3 Oct 2014 Measuring the Universe - (Kevin Pretorius)
Measuring the Universe, Kevin Pretorius (Farnham Astronomical Society)
Astronomical distances are based on a 'ladder' of measurements, starting with calculations of the distance from Earth to Moon - which in turn is based on calculations of the size of the Earth.
Educated people have known since 500BC or earlier that the Earth is 'round', however it was not until Eratosthenes (276-195 BC) that a reasonably accurate calculation was done to determine it's size (see Well at Syene).
To work out the distance to the Moon, you note the width of the Earths shadow as the Moon crosses it during a Lunar Eclipse and apply trigonometry .. as did Hipparchus in about 129BC, getting a value of about 65x Earth Dia., an overestimate of about 10%.
After this, various attempts were made to work out the distance from Earth to the Sun, however none of the calculations got close as the 'theory was wrong' - everyone was using a 'model' of the Solar System based on the (then obvious) 'Geocenteric' approach (Sun and planets all orbiting the Earth), so using trig. to work out the Earth-Sun distance always gave nonsense values (Ed. in modern Science, it is now recognised that 'nonsense answers' are one of the main 'clues' that your theory is 'wrong' (or at least incomplete) !)
Ed. Unfortunately the Geocentric model became an 'article of faith' to the Church, making it rather risky for anyone to put forward any other view (not that this stopped Copernicus, 1473-1543, who (perhaps sensibly) only published De revolutionibus orbium coelestium in the year of his death, however Galileo Galilei 1564-1642, spoke out in 1616 and went on to 'defend Copernicus' in Rome where was told by the Inquisition that heliocentrism was "foolish and absurd in philosophy (i.e science), and formally heretical since it explicitly contradicts in many places the sense of Holy Scripture" and, essentially, told to shut up. Of course he didn't, and in 1633 he found himself in front of the Pope again and this time was found to be 'vehemently suspected of heresy' (about once step away from being burnt at the stake) and was very lucky to only be sentenced to house arrest and have his books (including any future ones) banned. His books were removed from the 'banned' list some 200 yrs later (in 1835), however it took a Church Commission, instigated by Pope John Paul II in 1981 (some 12 years after Neil Armstrong and Buzz Aldrin had walked on the Moon), eleven years to decide, in 1992, "that the judge who condemned Galileo had erred" (thereby preserving the dogma of 'Papal Infallibility').
So it took some 1500 years for the 'model' to be corrected and for it to be understood that the Earth and the planets orbit the Sun. The big step was made by Kepler (1571-1630), who used Tycho Brahe's visual observational measurements to show that the planets (including Earth) followed elliptical orbits around the Sun and put into place the next 'step' of the 'ladder' by showing that a planets orbital period squared was proportional to it's semi-major axis (orbit) cubed (see Keplers Laws of Planetary Motion). However whilst this gave the 'relative' orbital distances of the planets from the Sun, an 'absolute' value for one of them was needed to work out all the others !
The 'rung' of the ladder was put in place when really accurate measurements became possible with the invention of the telescope in the early 1600's (often incorrectly credited to Galileo). So Cassini (1625-1712) and his assistant, Jean Richer, taking observations from 'opposite' sides of the Earth, used trig. to work out the orbit of Mars and thus all the other planets (he was only out by about 10%). Rev. James Gregory (1638-75) proposed an approach based on the transit of Venus (which happens in pairs, 8 years apart, every 110 years or so - James was born between the 1631/39 pair) to get a more accurate value - Edmund Halley (1656-1742) came up with the same approach 100 years later and this was used in 1761/69 (after Halley's death) to calculate the orbit of Venus. The next Venus transit pair in 1884/92, further refined the figures and led to todays value of Earth-Sun distance of 92 million miles.
Once you have the Earths orbit, you can use trig. to calculate the distance to the nearest stars (by measuring angles 6 months apart at opposite sides of the Earths orbit). This was first done by Bessel (1784-1846) for 61 Cygni (he got 11.4 LY, which is about right). By the start of the 1900's distances to many nearby stars had been calculated using the 'triangulation' method, however this method is limited to stars in our own Galaxy (the same method was used by ESA, 1989 Hipparcos mission to calculate the distances to about 118,00 stars, and will be used by Gaia, launched 2013 to measure about 16 billion).
So the next 'step' in the ladder is a change from simple trigonometry to measuring the brightness of light. It was Newton (1643-1727) who realised that the brightness of stars depended on their distance (the inverse square law) - he even used some clever reasoning (based on the brightness of Saturn) to deduce that 'the stars' were 'at least' 18-45,000 times further away than Saturn (too short by at least one order of magnitude, however this had more to do with the difficulty of estimating the brightness of the Sun than anything else)
It was only in 1911, when Hertzsprung and Russell took the trig. calculated distances to work out the 'absolute' brightness of the nearby stars that they found a plot of the absolute luminosity (actual brightness) v's 'spectral class' (colour) produced a 'band', (now known as the 'main sequence'). Knowing the 'spectral class' gives the actual luminosity of a star, so measuring it's apparent brightness allows the actual distance to be calculated.
Since it was possible to isolate a few stars at the edges of nearby galaxies, we thus also had the next step - distances to the nearby Galaxies. Working out the distances to Galaxies further away could be done by measuring the brightness of other objects, such as Cepheid Variables and Type 1A Supernovae etc.
However, the final step came with Hubble (1889-1953), with the discovery that the Universe was expanding, and the further 'red shifted' a Galaxies (stars) spectrum is, the further away it is (and the faster it is receding, however that's another subject). From red shifts we can calculate distances to the Galaxies right at the edge of the visible Universe !
This note last modified: 9th Nov 2014 14:44.