Saturn at Opposition

Saturn reaches opposition on the evening of the 23rd May. This means that Saturn, the Earth and the Sun all line up. The planet will be up all night from sunset to sunrise, and is at its closest to Earth at this time. On the downside, Saturn only gets about 20 degrees above the horizon so it never gets very high as you can see on the chart below.

On the plus side the rings are wide open and you should get some lovely views in any sized telescope.

Saturn has a lot of natural satellites (150 at the last count) but most of these are small lumps of rock. There are 7 large satellites, and of these Titan is the easiest to spot. Use planetarium software, web or magazines to find out where it is on any particular night.

Clear skies

Mercury’s greatest elongation on May 7th

On May 7th, Mercury will be at its furthest from the Sun as viewed from Earth. In other words, over the next few days, Mercury will be at its best to view in the evening sky. For UK observers look to the west-northwest about 80 to 90 minutes after sunset. Mercury will be low on the horizon as a naked eye object. Venus acts as a handy guide as Mercury will be about 22 degrees away from Venus on a line between that planet and the sun. 22 degrees is about the width of an outstretched hand at arms length.

The picture above shows Mercury and Venus on May 7th at 21:40 BST. Mercury is only about 8 degrees above the horizon at this time so you will need a clear view to the west-northwest.

Clear skies.

April’s talk: ‘The Consequenses of Contact’

Martin Griffiths is a Senior Lecturer with the University of South Wales. His talk was an enlightening examination of the policy for contacting aliens. There is a Rio (de Janeiro) scale of significance for rating any kind of possible alien report, ranging from 0 = no significance (e.g. it’s an abduction) to 10 = extraordinarily significant (e.g. it’s a NASA observation that contains an actual location). He added (rather tongue in cheek?) that if it’s 11 then they’re already here.

Dr Griffiths then discussed what kind of evidence we could find, such as a radio signal, alien artefact, probe in the vicinity, or direct contact from the aliens themselves. Because of the astronomical distances involved and the cost of sending any items through space, the remote contact would be more likely.

He then embarked on how we would try to understand the message. He harked back to our using mathematical symbols to communicate, but he said that is very limited, and really we should not worry if we cannot understand it; just getting it is the main thing! Does it really matter if we can’t interpret it?

Before you get too alarmed that the aliens may already be on their way to plunder our little blue heaven, Dr Griffiths reassured us that the aliens probably wouldn’t have the resources to reach us anyway. Not even NASA funds our search for ET now. And there are plenty of resources scattered around other solar systems already, so why should they want to use ours?

Dr Griffiths gave the impression that he was happy to keep things the way they are. Yes, it would be good to know that we are not alone, but astronomical distances are so vast that communication would be extremely limited and if we did actually come to meet aliens face to face we might stagnate if they took us over with their politics and beliefs. Interestingly, he said that they could easily be religious, as it is natural to create a religion to explain the unexplainable, and that most religions grow out from a minority that has been persecuted.

As you see, his talk was full of philosophical hypotheticals. Would we look after our planet better if we knew they were out there? My thought was yes, but he immediately pointed out that we already know how to improve things but we don’t. So, probably not!
Sadly, Dr Griffiths does not expect anyone to contact us.

But, if by any chance you do come across any aliens, his advice is to contact the UN General Secretary. (Ban Ki Moon, if I recall!)

Last month’s talk, February 2015

Yet another opportunity for our own Owen Brazell to cover for our planned speaker, who had to cancel.
‘Observing Planetary Nebulae’ was this well-polished offering.
The first one to be observed by human eye was M27 (the Dumbbell), by Charles Messier. M57 was incorporated by Messier into his catalogue, but it was first observed by Antoine Darquier, who described it as a ‘fading planet’
William Herschel could not make sense of them either and kept hoping that he could resolve them into stars if he could make a telescope big enough, but he failed to do so and decided they must be a fluid around a star condensing as it is being born. He discovered about 45, impressive stuff as the NGC has only 94!
Even Lord Rosse thought and said you could resolve a lot of them. (He of the Leviathan of Parsonstown fame)
William Huggins finally confirmed that they were nebulae when he produced a spectrum of the Cat’s Eye nebula (NGC 6543) and found it to be continuous.

Owen then explained how planetaries are formed, by stars nearing the end of their lives and throwing off their outer layers as their cores collapse to produce a white dwarf. The expanding nebula will then dissipate over 20-70 thousand years. The Boomerang nebula is the coldest area in the universe that we have so far seen, at 1 kelvin.

Planetaries are some of the few astronomical objects to show colour, usually a greenish hue. Filters and high magnifications help a lot. The O III filter passes light in the green area of the spectrum. The O III line is one of the few emission lines you will see in their spectra and that can be used as a distance marker for planetaries in other galaxies. This line was first identified as belonging to doubly ionised oxygen by Ira Bowen in 1927. Interestingly, he was mentioned in January’s talk – he conducted research with telescope eyepieces in order to work out optimum magnifications for various exit pupil sizes.

View the partial solar eclipse from Abingdon

On March 20th 2015, The Sun will be eclipsed by the Moon. From Abingdon up to 88% of the Sun will be covered. The society will have a selection of solar telescopes and eclipse glasses for members of the public to come and view this rare event. At maximum coverage the Sun will appear as a crescent with the horns pointing up. Maximum coverage is expected around 9:30am.

We will be set up in Abbey Meadows, near the Abbey Close car park (see the map below). We will be there between 8:30am and 10:30pm.

We won’t see another big partial eclipse like this till 2026 so make the most of this one.

Lets hope for clear skies.