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From: TerryMoselaol.com
Date: Mon, 13 Mar 2006 16:49:52 EST
Subject: PLE, TV, Lectures
Hi all,
1. PLE: Just another reminder about the Penumbral Lunar Eclipse on March 14
- 15. This will be barely noticeable to most people, but experienced
observers may notice that the Full Moon is not quite as bright as usual, and see a
slight dimming of the Moon's SSW edge, the part closest to the umbra, the
central and darkest part of the Earth's shadow. The moon passes completely inside
the penumbra, or 'partial shadow', of the Earth, but no part of it actually
enters the umbra, which would give a partial eclipse. So this is what is
called a 'Total Penumbral Eclipse' - not to be confused with a Total Lunar
Eclipse! It begins on 21h 22m and ends on 02h 14m. The Moon will be just on the
border between Leo and Virgo, quite close to Beta Virginis.
Of academic interest only, I'm afraid, but I attach a map anyway. If you are
wondering why the Earth's shadow is not centred on the ecliptic (the
diagonal line running from top right to bottom left) on that map, it's because that
is the view as seen from Belfast (about 55 degrees North), rather than the
'theoretical' geocentric view. That caused some surprise to a certain
professional astronomer, but I assure you that it's correct!
In case you're not sure what's what, the inner dark circle is the Earth's
'full' shadow, or umbra: if the whole Moon was inside this, it would be a
'total lunar eclipse'. If only part of the Moon was inside it, it would be a
'partial lunar eclipse'. The outer lighter ring is the penumbra, or partial
shadow of the Earth. Since the Moon (yellow disc) is all inside this ring, it's
a 'penumbral lunar eclipse'. If only part of the Moon was inside that ring, it
would be a 'partial penumbral lunar eclipse'.
2. TV: Sat, 18 Mar, 12.30pm, BBC2 TV: The Sky at Night - about Saturn.
LECTURES:
3. 20 March, 8 p.m. The Irish Astronomical Society's next talk is "Worlds
that Never Were" (Curious Episodes in the History of Astronomy) to be given by
the indomitable Mr John Flannery (IAS) on March 20 in Ely House, Ely Place,
Dublin.
4. 22 March, 7.30 p.m., Lecture Room 5, Stranmillis College, Belfast: IAA
Public Lecture, "The Solar Wind: from Explosions on the Sun to Us", by the
redoubtable Dr Miruna Popescu of Armagh Observatory (Doctorate just awarded -
congratulations!). I can't resist quoting most of her synopsis:
"A few million tonnes of charged particles (plasma) leave the Sun every
second. This continuous stream of electrons, protons and heavier ions - the
solar wind - flows into the space between the planets and even beyond. The
solar wind flows with a huge speed, equivalent to London to New York in about 10
seconds!
Sometimes the solar wind that reaches the Earth distorts its protective
magnetic field, producing geomagnetic storms that can perturb satellites and
electronic systems, and sometimes create the most amazing cosmic light displays:
aurorae - also known as the northern lights in our hemisphere.
How does the solar wind escape the Sun's huge gravity and leak into space?
How does it reach such high speeds?
What are its effects on the Earth's environment?
How do we know that the solar wind is out there, constantly surrounding our
planet?
What are the most up-to-date discoveries that we have made about the solar
wind?
These are some of the questions I am going to answer in my talk.
Prepare yourselves to see some of the most amazing images and movies of
our Sun, taken with the most accurate solar instruments. Fasten your
seat-belts as you are going to fly around the Sun with SoHO and TRACE!" (I can't
wait! TM)
Admission free, and all are welcome, including light refreshments.
5. Messier Marathon: The EAAS will be attempting a 'Messier Marathon', i.e
trying to observe all the Messier objects between dusk and dawn, on the night
of 24/25 March. Obviously that's weather dependant, so more details later.
Clear Skies,
Terry Moseley
aol.com Date: Mon, 13 Mar 2006 16:49:52 EST Subject: PLE, TV, Lectures Hi all, 1. PLE: Just another reminder about the Penumbral Lunar Eclipse on March 14 - 15. This will be barely noticeable to most people, but experienced observers may notice that the Full Moon is not quite as bright as usual, and see a slight dimming of the Moon's SSW edge, the part closest to the umbra, the central and darkest part of the Earth's shadow. The moon passes completely inside the penumbra, or 'partial shadow', of the Earth, but no part of it actually enters the umbra, which would give a partial eclipse. So this is what is called a 'Total Penumbral Eclipse' - not to be confused with a Total Lunar Eclipse! It begins on 21h 22m and ends on 02h 14m. The Moon will be just on the border between Leo and Virgo, quite close to Beta Virginis. Of academic interest only, I'm afraid, but I attach a map anyway. If you are wondering why the Earth's shadow is not centred on the ecliptic (the diagonal line running from top right to bottom left) on that map, it's because that is the view as seen from Belfast (about 55 degrees North), rather than the 'theoretical' geocentric view. That caused some surprise to a certain professional astronomer, but I assure you that it's correct! In case you're not sure what's what, the inner dark circle is the Earth's 'full' shadow, or umbra: if the whole Moon was inside this, it would be a 'total lunar eclipse'. If only part of the Moon was inside it, it would be a 'partial lunar eclipse'. The outer lighter ring is the penumbra, or partial shadow of the Earth. Since the Moon (yellow disc) is all inside this ring, it's a 'penumbral lunar eclipse'. If only part of the Moon was inside that ring, it would be a 'partial penumbral lunar eclipse'. 2. TV: Sat, 18 Mar, 12.30pm, BBC2 TV: The Sky at Night - about Saturn. LECTURES: 3. 20 March, 8 p.m. The Irish Astronomical Society's next talk is "Worlds that Never Were" (Curious Episodes in the History of Astronomy) to be given by the indomitable Mr John Flannery (IAS) on March 20 in Ely House, Ely Place, Dublin. 4. 22 March, 7.30 p.m., Lecture Room 5, Stranmillis College, Belfast: IAA Public Lecture, "The Solar Wind: from Explosions on the Sun to Us", by the redoubtable Dr Miruna Popescu of Armagh Observatory (Doctorate just awarded - congratulations!). I can't resist quoting most of her synopsis: "A few million tonnes of charged particles (plasma) leave the Sun every second. This continuous stream of electrons, protons and heavier ions - the solar wind - flows into the space between the planets and even beyond. The solar wind flows with a huge speed, equivalent to London to New York in about 10 seconds! Sometimes the solar wind that reaches the Earth distorts its protective magnetic field, producing geomagnetic storms that can perturb satellites and electronic systems, and sometimes create the most amazing cosmic light displays: aurorae - also known as the northern lights in our hemisphere. How does the solar wind escape the Sun's huge gravity and leak into space? How does it reach such high speeds? What are its effects on the Earth's environment? How do we know that the solar wind is out there, constantly surrounding our planet? What are the most up-to-date discoveries that we have made about the solar wind? These are some of the questions I am going to answer in my talk. Prepare yourselves to see some of the most amazing images and movies of our Sun, taken with the most accurate solar instruments. Fasten your seat-belts as you are going to fly around the Sun with SoHO and TRACE!" (I can't wait! TM) Admission free, and all are welcome, including light refreshments. 5. Messier Marathon: The EAAS will be attempting a 'Messier Marathon', i.e trying to observe all the Messier objects between dusk and dawn, on the night of 24/25 March. Obviously that's weather dependant, so more details later. Clear Skies, Terry Moseley
