Saturday, 5 July 2014

July Meeting- The Moon

A good attendance for our final meeting before September.
We had 31 in attendance including a couple - Mike & Linda from Newcastle Emlyn (?) I think it was.
We also had a space scientist - Philippa Berry, from Roch, - with us and we are currently in the process of encouraging her to talk to us on her specialist subject - satellite altimetry - in the new year.

Kim started the evening off with the "What's Up in July" feature - here he is looking suitably focussed prior to the delivery of his material.

At this time of year the sky is never really dark so aside from planets Mars & Saturn before midnight and Venus just before dawn viewing is an unsocial hours experience.

Kim commenced with the Moon which, in most months, is a stunning sight visually.

A focus was on the Cygnus constellation high in the sky at this time and visible for many months to come.

Kim hilighted some of the more obscure features of this grouping - the Blinking Planetary (not a euphemism he said!!) was one.

Getting pictures of the meeting is challenging - you lose friends when you point a camera at them - but I caught a number in the tea-room without their spotting me.

  New member Linda is in the foreground (left) with Mike across the aisle.

 To the right more studious members are concentrating on the business at hand.

 The main lecture this month was on the Moon and delivered by Mike.

Much of this material was drawn from:
 world of

Here we have a better picture of those in attendance.

There is a link to the presentation below and notes to accompany the slides (where there were some) are also printed below for reference.

Slide 3 – The Moon is the 5th largest moon in solar system - behind three of the Galilean moons of Jupiter (Ganymede, Callisto and Io) and Saturn’s largest moon, Titan. To put its size in perspective, the diameter of the Moon is approximately the same as the distance between London and Cairo.

The distance to the Moon is known accurately due to reflectors that were placed on it during the Apollo missions. The reflectors, part of the Lunar Laser Ranging Experiment, allow lasers to be shone onto the Moon and the time taken for the laser light to get there and back can be measured. It is then possible, using a simple equation, to calculate the distance to the Moon.

Slide 4 - Information first gathered during the Apollo era suggested that the Moon was formed when a Mars-sized body hit the Earth during its early history. This impact occurred after the Earth's iron core had formed. Rocky, iron-poor material was ejected into orbit and then coalesced to form the moon. Recently, the Lunar Prospector spacecraft has confirmed that the Moon has a small core, supporting the Mars sized impact theory.
Similarities in the mineral composition of the Earth and the Moon indicate that they share a common origin. However, if they had simply formed form the same cloud of rocks and dust, the Moon would have a core similar in proportion to the Earth's.
Slide 5 -

Man's limited knowledge of the Lunar interior comes primarily from seismic monitoring of lunar quakes, and from tracking spacecraft orbiting the moon. During Apollo missions 12, 14, 15, and 16, sensitive, seismic instruments were placed upon the lunar surface. These instruments detected mild moon quakes, some of which originated in the upper mantle and some deeper within. They also recorded occasional impacts (some natural and some man made) on the lunar surface. By monitoring how the quake/impact shock waves, of varying frequencies, propagate around and through the moon, scientists obtain a hint as to the nature of the lunar interior. 

Slide 16 -  Van Gogh sold only one painting in his life.

From Don McLean's song 'Vincent' (Starry, Starry Night) (Based on the Painting), to the endless number of merchandise products sporting this image, it is nearly impossible to shy away from this amazing painting.

The Starry Night, 1889, painted in Europe and showing a C-shaped crescent, so this must be pre-dawn, not the evening sky. Or did van Gogh get it wrong?

Slide 17 - Although there is a full Moon every month, it revisits the same point in the sky on the same date only once every 19 years. 

The Dutch master painted Moonrise or Rising Moon during the summer of 1889 while staying in Saint-Rémy-de-Provence in southern France. But the exact moment depicted in the landscape has eluded art historians.

To solve the mystery, the team travelled to Saint-Rémy-de-Provence in June 2002 and identified landmarks in the painting. These include an overhanging cliff that obscures a wedge of the luminous orange Moon, and a distant double-roofed house.

Based on these, the team worked out where van Gogh was standing when he painted the canvas. They measured the compass direction along which the Moon appeared to him, and the height of the cliff above the horizon.

Using lunar tables and astronomy software, they then calculated the time and dates at which a rising full Moon would appear above the horizon at that spot: 16 May and 13 July 1889. Because the wheat in the painting is golden and harvested, it must be the July date, they conclude.

Slide 26 - Scientists investigated Shackleton Crater, which sits almost directly on the moon's south pole. The crater, named after the Antarctic explorer Ernest Shackleton, is more than 12 miles wide (19 kilometers) and 2 miles deep (3 km) — about as deep as Earth's oceans.

The interiors of polar craters on the moon are in nearly perpetual darkness, making them cold traps that researchers have long suspected might be home to vast amounts of frozen water and thus key candidates for human exploration. However, previous orbital and Earth-based observations of lunar craters have yielded conflicting interpretations over whether ice is there.
 Click on link below for presentation
  Moon Presentation

Our next meeting at Letterston will be in September but keep watch on the forum for news of our Solar day at Newgale - currently scheduled, weather permitting, for Saturday August 9th at 12.00 hrs with the possibility of a further event to view the Perseid meteor shower which peaks on the 12th.