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THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 467 2018 April 22

Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is arguably Britain's liveliest astronomical
society, with members all over the world. We accept subscription
payments online at our secure site and can take credit and debit
cards. You can join or renew via a secure server or just see how
much we have to offer by visiting


With little warning, on April 15 a 'Tunguska-class' asteroid flew through
the Earth--Moon system. 2018 GE3 was discovered just the day before as it
plunged towards the Sun from the asteroid belt. The asteroid is estimated
to be 48 to 120 metres in diameter; in all of observational history it is
the largest known asteroid to pass so close to the Earth.

International Centre for Radio Astronomy Research

A telescope in the Western Australia outback has been used to listen to a
mysterious cigar-shaped object that entered our Solar System late last year.
The unusual object -- known as 'Oumuamua -- came from another solar system,
prompting speculation it could be an alien spacecraft. So astronomers went
back through observations from the Murchison Widefield Array (MWA) telescope
to check for radio transmissions coming from the object between the
frequencies of 72 and 102 MHz -- similar to the frequency range in which FM
radio is broadcast. While they did not find any signs of intelligent life,
the research helped to expand the search for extra-terrestrial intelligence
(SETI) from distant stars to objects closer to home. When 'Oumuamua was
first discovered, astronomers thought it was a comet or an asteroid from
within the Solar System. But after studying its orbit and discovering its
long, cylindrical shape, they realised 'Oumuamua was neither, and had come
from interstellar space. Telescopes around the world observed the visitor
in an effort to learn as much as possible about it before it headed back out
of the Solar System, becoming too faint to observe in detail. The MWA is
located in Western Australia's remote Murchison region, one of the most
radio-quiet areas on the planet and far from human activity and radio
interference caused by technology. It is made up of thousands of antennae
attached to hundreds of 'tiles' that dot the ancient landscape, relentlessly
observing the heavens day after day, night after night. The research team
was able to look back through all of the MWA's observations from November,
December and early January, when 'Oumuamua was between 95 million and 590
million kilometres from the Earth. They found nothing, but as the first
object of its class to be discovered, `Oumuamua has given us an interesting
opportunity to expand the search for extra-terrestrial intelligence from
traditional targets such as stars and galaxies to objects that are much
closer. That also allows for searches for transmitters that are many orders
of magnitude less powerful than those that would be needed to be detectable
from a planet orbiting even the nearest stars.
'Oumuamua was first discovered by the Pan-STARRS project at the University
of Hawaii in October. Its name loosely means 'a messenger that reaches out
from the distant past' in Hawaiian, and is the first object known to be
interstellar to pass through our Solar System. Combining observations from
a host of telescopes, scientists have determined that `Oumuamua is most
likely a cometary fragment that has lost much of its surface water because
it was bombarded by cosmic rays on its long journey through interstellar
space. Researchers have now suggested there could be more than 46 million
similar interstellar objects crossing the Solar System every year. While
most of such objects must be too far away to study with current technology,
future telescopes such as the Square Kilometre Array (SKA) should enable
scientists to understand more about such interstellar interlopers.

Columbia University

A team of astrophysicists has discovered a dozen black holes gathered round
Sagittarius A* (Sgr A*), the supermassive black hole at the centre of the
Milky Way Galaxy. The finding is the first to support a decades-old
prediction, opening up opportunities to understand the Universe better.
For more than twenty years, researchers have searched unsuccessfully for
evidence to support a theory that thousands of black holes surround super-
massive black holes (SMBHs) at the centres of large galaxies. There are
only about five dozen known black holes in our entire Galaxy -- 100,000
light-years across -- and there are supposed to be 10,000 to 20,000 that no
one has been able to find, in a region just six light-years wide. Sgr A*
is surrounded by a halo of gas and dust that provides the perfect breeding
ground for the birth of massive stars, which live, die and could turn into
black holes there. Additionally, black holes from outside the halo are
believed to fall under the influence of the SMBH as they lose their energy,
causing them to be pulled into the vicinity of the SMBH, where they are held
captive by its force. While most of the trapped black holes remain
isolated, some capture and bind to a passing star, forming a stellar binary.
Researchers believe that there is a heavy concentration of such isolated and
mated black holes in the Galactic Centre, forming a density cusp which gets
more crowded as distance to the SMBH decreases. In the past, failed
attempts to find evidence of such a cusp have focused on looking for the
bright burst of X-ray glow that sometimes occurs in black-hole binaries.
Astronomers turned to archival data from the Chandra X-ray Observatory to
test their technique. They searched for X-ray signatures of black-hole--
low-mass-binaries in their inactive state and were able to find 12 within
three light-years of Sgr A*. The researchers then analyzed the properties
and spatial distribution of the identified binary systems and extrapolated
from their observations that there must be anywhere from 300 to 500 black-
hole--low-mass-binaries and about 10,000 isolated black holes in the region
surrounding Sgr A*.


New data from the MUSE instrument on ESO's Very Large Telescope in Chile
have revealed a remarkable ring of gas in a system called 1E 0102.2-7219,
expanding slowly within the depths of numerous other fast-moving filaments
of gas and dust left behind after a supernova explosion that took place 2000
years ago in the Small Magellanic Cloud. That discovery allowed astronomers
to identify for the first time an isolated neutron star with low magnetic
field located beyond our own Milky Way galaxy. The team noticed that the
ring was centred on an X-ray source that had been noted years before and
designated p1. The nature of that source had remained a mystery. In
particular, it was not clear whether p1 actually lies inside the remnant or
behind it. It was only when the ring of gas -- which includes both neon and
oxygen -- was observed with MUSE that the scientific team noticed that it
perfectly circled p1. The coincidence was too great, and they realised that
p1 must lie within the supernova remnant itself. Once p1's location was
known, the team used existing X-ray observations of it from the Chandra
X-ray Observatory to determine that it must be an isolated neutron star,
with a low magnetic field. When massive stars explode as supernovae, they
leave behind curdled webs of hot gas and dust, known as supernova remnants.
Those turbulent structures are key to the redistribution of the heavier
elements -- which are cooked up by massive stars as they live and die --
into the interstellar medium, where they eventually form new stars and
planets. Typically barely ten kilometres across, yet with masses more than
our Sun's, isolated neutron stars with low magnetic fields are thought to be
abundant across the Universe, but they are very hard to find because they
shine only at X-ray wavelengths. The fact that the confirmation of p1 as an
isolated neutron star was enabled by optical observations is thus
particularly exciting.

NASA/Goddard Space Flight Center

Astronomers using the Hubble Space Telescope have for the first time
measured the distance to one of the oldest objects in the Universe, a
collection of stars born shortly after the Big Bang. That stellar assembly,
a globular star cluster called NGC 6397, is one of the closest such clusters
to the Earth. The new measurement sets the cluster's distance at 7,800
light-years, with just a 3% margin of error. That refined distance
yardstick provides an independent estimate for the age of the Universe.
The new measurement may also help astronomers to improve models of stellar
evolution. Star clusters are the key ingredient in stellar models, because
the stars in each grouping are at the same distance and have the same age
and the same chemical composition. They therefore constitute a single
stellar population to study. Until now, astronomers have estimated the
distances to our Galaxy's globular clusters by comparing the luminosities
and colours of stars to theoretical models, and to the luminosities and
colours of similar stars in the solar neighbourhood. But the accuracy of
those estimates varies, with uncertainties between 10 and 20%. However,
the new measurement relies on straightforward trigonometry. Using a novel
observational technique to measure tiny angles on the sky, astronomers
managed to stretch Hubble's yardstick beyond the disc of our Milky Way
The research team calculated NGC 6397's age at 13.4 billion years old.
The globular clusters are so old that if their ages and distances deduced
from models are off by a little bit, they can seem to be older than the age
of the Universe. Accurate distances to globular clusters are used as
references in stellar models to study the characteristics of young and old
stellar populations. A model that agrees with the measurements inspires
some faith in its application to more distant stars. The nearby star
clusters serve as anchors for the stellar models. Until now, we only had
accurate distances to the much younger open clusters inside our Galaxy,
because they are closer to the Earth. By contrast, about 150 globular
clusters orbit outside our Galaxy's comparatively younger starry disc.
The Hubble astronomers used the trigonometrical parallax method to obtain
the cluster's distance. To obtain the distance to NGC 6397, the team
employed a method to measure accurate distances to pulsating stars called
Cepheid variables, which serve as reliable distance markers for astronomers
to calculate accurately the expansion rate of the Universe. With that
technique, called 'spatial scanning', Hubble's Wide-Field Camera 3 gauged
the parallaxes of 40 NGC 6397 cluster stars, making measurements every six
months for two years. The researchers then combined the results to obtain
the precise distance measurement. They say that they could reach an
accuracy of 1% if they combine the Hubble distance measurement of NGC 6397
with the results that are hoped to be obtained from ESA's Gaia space
observatory, which is measuring the positions and distances of stars with
unprecedented precision. The data release for the second batch of stars in
that survey is scheduled for late April.


Phosphorus is an essential element for life -- but new findings suggest that
it might just have been a matter of luck that there was enough of it for
life to start on Earth. According to new observations of the Crab Nebula
(the remnant of a supernova recorded by Chinese astronomers in 1054), the
abundance and distribution of phosphorus in the Milky Way galaxy may be more
random than scientists previously thought. As such, some places in the
galaxy may not have enough phosphorus to support life, even if they are home
to otherwise hospitable exoplanets. Most of the Universe's phosphorus was
created during the last gasps of dying massive stars or in supernovae.
Phosphorus is difficult to observe, and only in 2013 did astronomers make
the first measurements of the element in a stellar explosion, in the wispy
remains of the supernova Cassiopeia A. Surprisingly, they found a relative
abundance of phosphorus up to 100 times greater than is observed in the rest
of the Milky Way.
But that might have been an outlier. Recently, astronomers pointed the
William Herschel Telescope in the Canary Islands towards the Crab Nebula,
located about 6,500 light-years away. Preliminary data show an amount of
phosphorus more similar to the values found in the interstellar gas and dust
of the Milky Way -- a pittance compared with the abundance in Cassiopeia A.
Phosphorus abundances are remarkably variable from one site to another. The
star that created Cassiopeia A is roughly twice as massive as the one that
made the Crab Nebula. A more massive star could have generated different
reactions that produced more phosphorus. The researchers said that if the
production of phosphorus varies widely across the Galaxy, so might the like-
lihood of life on other planets. Even if a planet had every other condition
needed for habitability, it might still be bereft of life because it formed
where there was a dearth of phosphorus. But the observations are still
preliminary. The astronomers were able to measure only parts of the nebula
before clouds and a snowstorm curtailed their observing run. Still, the
data they do have show significantly less phosphorus in the Crab Nebula than
in Cassiopeia A. Ultimately, astronomers will need to measure phosphorus in
other supernova remnants. They really want to look at how it is spreading
out from supernova remnants and falling back into the interstellar medium.

DOE/Lawrence Berkeley National Laboratory

Scientists have decoded faint distortions in the patterns of the Universe's
earliest light to map huge tube-like structures known as filaments --
invisible to our eyes -- that serve as highways for delivering matter to
dense hubs such as galaxy clusters. The international scientific team
analyzed data from past sky surveys using sophisticated image-recognition
technology to home in on the gravity-based effects that identify the shapes
of the filaments. They also used models and theories about the filaments
to help guide and interpret their analysis. The detailed exploration of
filaments will help researchers to understand better the formation and
evolution of the cosmic web -- the large-scale structure of matter in the
Universe -- including the unseen stuff known as dark matter that seems to
make up about 85% of the total mass of the Universe. Dark matter constitutes
the filaments -- which researchers learned typically stretch across hundreds
of millions of light-years -- and the so-called haloes that host clusters of
galaxies are fed by the universal network of filaments. More studies of
filaments might provide new insights about dark energy, another problematic
entity that seems to drive the accelerating expansion of the Universe.
Filament properties could also put gravity theories to the test, including
Einstein's theory of general relativity, and lend important clues to help
solve an apparent mismatch in the amount of visible matter predicted to
exist in the Universe -- the 'missing baryon' problem.
The study used data from the Baryon Oscillation Spectroscopic Survey, or
BOSS, an Earth-based sky survey that captured light from about 1.5 million
galaxies to study the Universe's expansion and the patterned distribution of
matter in the Universe set in motion by the propagation of sound waves, or
'baryonic acoustic oscillations', rippling in the early Universe. The BOSS
survey team produced a catalogue of probable filament structures that
connected clusters of matter that researchers identified in the latest
study. Researchers also relied on precise, space-based measurements of the
cosmic microwave background, or CMB, which is the nearly uniform remnant
signal from the first light of the Universe. While that light signature is
very similar across the Universe, there are regular fluctuations that have
been mapped in previous surveys. In the latest study, researchers focused
on patterned fluctuations in the CMB. They used sophisticated computer
algorithms to seek out the imprint of filaments from gravity-based
distortions in the CMB, known as weak lensing effects, that are caused by
the CMB light passing through matter. Since galaxies live in the densest
regions of the Universe, the weak lensing signal from the deflection of CMB
light is strongest from those parts. Dark matter resides in the haloes
around those galaxies, and was also known to spread from those denser areas
in filaments. New data from existing experiments, and next-generation sky
surveys such as the Dark Energy Spectroscopic Instrument (DESI) now under
construction at Kitt Peak, should provide even more detailed data about the
filaments. Researchers noted that this important step in sleuthing the
shapes and locations of filaments should also be useful for focused studies
that seek to identify what types of gases inhabit the filaments, the
temperatures of those gases, and the mechanisms for how particles enter and
move around in the filaments. The study also allows them to determine the
lengths of filaments.
Bulletin compiled by Clive Down (c) 2018 The Society for Popular Astronomy
The Society for Popular Astronomy has been helping beginners in amateur
astronomy -- and more experienced observers -- for over 60 years. If you
are not a member, you may be missing something. Membership rates are
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For those of you who use online photo storage:

We’re excited to announce that Flickr has agreed to be acquired by SmugMug, the photography platform dedicated to visual storytellers.
SmugMug has a long history of empowering people who love photography and who want to improve their craft, making them a perfect fit for Flickr and our creative community. With SmugMug, we’ll continue to focus on you, the Flickr members who inspire us all with your work.
Nothing will change immediately with regard to your Flickr account. You will still access Flickr with your current login credentials and you will have the same Flickr experience as you do now. We will continue to work to make your Flickr experience even better.
We think you are going to love Flickr under SmugMug ownership, but you can choose to not have your Flickr account and data transferred to SmugMug until May 25, 2018. If you want to keep your Flickr account and data from being transferred, you must go to your Flickr account to download the photos and videos you want to keep, then delete your account from your Account Settings by May 25, 2018.
If you do not delete your account by May 25, 2018, your Flickr account and data will transfer to SmugMug and will be governed by SmugMug’s Terms and Privacy Policy.
Read more detailed FAQs about this transition on the Flickr Blog.
We’re happy that Flickr is your home for photography and we look forward to the next chapter in our adventure together as we join the SmugMug family.
The Flickr Team

Hywel Dda – Our Big NHS Change” – Drop In Events
We have a once-in-a-lifetime chance to fundamentally change the way that we provide local healthcare services for the better – and we want to hear what you have to say about it.
“Hywel Dda - Our Big NHS Change” was officially launched at a meeting of the health board on Thursday 19 April 2018, marking the start of a 12-week public consultation aimed at making provision of local health and care better for our communities.
We’re asking residents across Carmarthenshire, Ceredigion and Pembrokeshire, as well as the wider cross-border regions, to get involved and have your say on three proposals to improve the way we provide care for our population. Each proposal has been designed and tested by our clinicians to ensure that our services are safe, sustainable, accessible and kind for our generation and those to come.
How can you get involved?
Hywel Dda University Health Board are holding a series of public drop in events across Carmarthenshire, Ceredigion and Pembrokeshire.
Our doctors, nurses and therapists want to talk to you about “Our big NHS Change” proposals for Carmarthenshire, Ceredigion and Pembrokeshire and listen to your views.
These are informal Drop In Events. Please come along at any time between 2pm and 7pm to find out more. This is your opportunity to tell us what you think or give us new ideas.
2pm – 7pm   4 May 2018   The Great Hall, Guildhall Cardigan   SA43 1JL
2pm – 7pm   8 May 2018   St Peter’s Civic Hall, Carmarthen   SA31 1PG
2pm – 7pm   11 May 2018   Regency Hall, Saundersfoot   SA69 9NG
2pm – 7pm   15 May 2018   Letterston Memorial Hall, Letterston    SA62 5RY
2pm – 7pm   18 May 2018   Morlan Centre, Aberystwyth   SY23 2HH
2pm – 7pm   22 May 2018   Selwyn Samuel Centre, Llanelli    SA15 3AE
2pm – 7pm   24 May 2018   Llandybie Memorial Hall, Llandybie   SA18 3UR
For more information go to
Please share this information with your colleagues and anyone else who may be interested and, where appropriate, please place the attached poster in public areas.
If you would like more copies of the poster please can you telephone 01554 899056 or email[/email]][email][/email]

Photography / April: Looking at Shutter Speed 'Homework'
« on: April 17, 2018, 11:56:05 AM »
Homework..... Anyone can try this whether you were at the April meeting or not:

Find something you can photograph in two different ways using fast and slow shutter speeds for different results.  Moving people or vehicles works great, or you can do something as simple as water running from a tap.

Use a tripod & a cable release with slow shutter speeds for the best results.

We will be looking at "Aperture and Depth of Field"

THE SOCIETY FOR POPULAR ASTRONOMY Electronic News Bulletin No. 466 2018 April 8
Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is arguably Britain's liveliest astronomical
society, with members all over the world. We accept subscription
payments online at our secure site and can take credit and debit
cards. You can join or renew via a secure server or just see how
much we have to offer by visiting


InSight -- short for Interior Exploration using Seismic Investigations,
Geodesy and Heat Transport -- is a stationary lander scheduled to be
launched towards Mars as soon as May 5. It will be the first mission ever
dedicated to Mars' deep interior, and the first NASA mission since the
Apollo moon landings to place a seismometer on the soil of another planet.
Scientists hope that by detecting marsquakes and other phenomena inside the
planet, InSight can enable them to understand how Mars formed. InSight
carries a suite of sensitive instruments to gather such data; unlike a rover
mission, they require a spacecraft that sits still and carefully places its
instruments on the Martian surface. NASA is not the only agency excited
about the mission. Several European partners contributed instruments, or
instrument components. For example, France's Centre National d'Etudes
Spatiales (CNES) led a multinational team that built an ultra-sensitive
seismometer for detecting marsquakes. The German Aerospace Center (DLR)
developed a thermal probe that can bury itself up to 5 metres underground
and measure heat flowing from inside the planet. Looking deep into Mars
will let scientists understand how different its crust, mantle and core are
from their counterparts on Earth. In a sense, Mars is the exo-planet next
door -- a nearby example of how gas, dust and heat combine and arrange
themselves into a planet.


New research finds that 'Oumuamua, the rocky object identified as the first
confirmed interstellar asteroid, very likely came from a binary-star system.
For the new study, astronomers set about testing how efficient binary-star
systems are at ejecting objects. They also looked at how common such star
systems are in the Galaxy. They found that rocky objects like 'Oumuamua are
far more likely to come from binary- than single-star systems. They were
also able to determine that rocky objects are ejected from binary systems in
comparable numbers to icy objects. Astronomers claim that it is really odd
that the first object we would see from outside our system would be an
asteroid, because a comet would be a lot easier to spot and the Solar System
ejects many more comets than asteroids. Once they determined that binary
systems are very efficient at ejecting rocky objects, and that a sufficient
number of them exists, they were satisfied that 'Oumuamua very likely came
from a binary system. They also concluded that it probably came from a
system with a relatively hot, high-mass star, since such a system would have
a greater number of rocky objects closer in. The team suggests that the
asteroid was very likely to have been ejected from its binary system some
time during the formation of planets.
'Oumuamua, which is Hawaiian for 'scout', was first observed by the
Haleakala Observatory in Hawaii on 2017 October 19. With a radius of 200
metres and travelling at 30 kilometres per second, at its closest it was
about 33 million km from the Earth. When it was first discovered,
researchers assumed that it was a comet. But it did not show any comet-like
activity as it neared the Sun, so it seemed that it must be rocky, and it
was quickly re-classified as an asteroid. Researchers were also fairly sure
it was from outside the Solar System, on the basis of its trajectory and
speed. An eccentricity of 1.2 -- which classifies its path as an open-ended
hyperbolic orbit -- and such a high speed meant that it was not bound by the
gravity of the Sun. In fact, 'Oumuamua's orbit has the highest eccentricity
ever observed in an object passing through the Solar System. Major
questions about 'Oumuamua remain. For planetary scientists, being able to
observe such objects may yield important clues about how planet formation
works in other star systems.

FECYT - Spanish Foundation for Science and Technology

About 70,000 years ago, a small reddish star approached the Solar System and
gravitationally disturbed comets and asteroids. Astronomers have verified
that the movement of some of those objects is still marked by that stellar
encounter. At a time when modern humans were beginning to leave Africa and
the Neanderthals were living on our planet, Scholz's star -- named after the
German astronomer who discovered it -- approached within less than a light-
year from the Sun. Nowadays it is almost 20 light-years away, but 70,000
years ago it entered the Oort cloud, a reservoir of trans-Neptunian objects
located in the confines of the Solar System. Now astronomers have analyzed
for the first time the nearly 340 objects of the Solar System with hyper-
bolic orbits, and in doing so they have detected that the trajectories of
some of them are influenced by the passage of Scholz's star. Using numerical
simulations they calculated the radiants or positions in the sky from which
all these hyperbolic objects seem to come. In principle, one would expect
such positions to be evenly distributed in the sky, particularly if the
objects come from the Oort cloud; however, what is found is very different:
a statistically significant accumulation of radiants. The pronounced over-
density appears projected in the direction of the constellation of Gemini,
which fits the close encounter with Scholz's star.
The time at which that star passed close to us and its position during
prehistory coincide with the data of the new investigation. It could be a
coincidence, but it is unlikely that both location and time would be
compatible just by coincidence. The simulations suggest that Scholz's star
approached even closer than the 0.6 light-years pointed out in a 2015 study
as the lower limit. The close fly-by of the star 70,000 years ago did not
disturb all the hyperbolic objects of the Solar System, only those that were
closest to it at that time. For example, the radiant of the interstellar
asteroid `Oumuamua is in the constellation Lyra, very far from Gemini, so it
is not part of the detected over-density. Scholz's star is actually a
binary system formed by a small red dwarf, with about 9% of the mass of the
Sun, around which a still less bright and smaller brown dwarf orbits. Some
of our distant ancestors may have seen its faint reddish light with their
naked eyes in the nights of prehistory.


A team of astronomers found 72 very bright, but quick, events in a recent
survey, and are still struggling to explain their origin. The scientists
found the transients in data from the Dark Energy Survey Supernova Programme
(DES-SN). That is part of a global effort to understand dark energy, an
entity that seems to be driving an acceleration in the expansion of the
Universe. DES-SN uses a large camera on the 4-metre telescope at the Cerro
Tololo Inter-American Observatory (CTIO) in the Chilean Andes. The survey
looks for supernovae, the explosion of massive stars at the end of their
lives. A supernova explosion can briefly be as bright as a whole galaxy.
The team found the largest number of those quick events to date. Even for
transient phenomena, they are very peculiar: while they have a similar
maximum brightness to different types of supernovae they are visible for
shorter times, from a week to a month. In contrast, supernovae last for
several months or more. The events appear to be both hot, with temperatures
from 10,000 to 30,000 degrees Celsius, and large, ranging in size from
several up to a hundred times the distance from the Earth to the Sun. They
also seem to be expanding and cooling as they evolve in time, as would be
expected from an exploding event such as a supernova. There is still debate
on the origin of these transients. One possible scenario is that the star
sheds a lot of material before a supernova explosion, and in extreme cases
could be completely enveloped by a shroud of matter. The supernova itself
may then heat the surrounding material to very high temperatures. In that
case astronomers see the hot cloud rather than the exploding star itself.
To confirm any of that, the team will need a lot more data. For the future,
the team plans to continue its search for transients, and estimate how often
they occur compared with more 'routine' supernovae.

University of Notre Dame

The slow fade of radioactive elements in a supernova allows astrophysicists
to study them at length. But the Universe is full of flash-in-the-pan
transient events lasting only a brief time, so quick and hard to study that
they remain a mystery. Only by increasing the rate at which telescopes
monitor the sky has it been possible to catch more Fast-Evolving Luminous
Transients (FELTs) and begin to understand them. According to a new study,
researchers say that the Kepler space telescope captured one of the fastest
FELTs to date. The FELT, captured in 2015, rose in brightness over just 2.2
days and faded completely within 10 days. Most supernovae can take 20 days
to reach peak brightness and weeks to become undetectable. Researchers
debated what could be causing these particularly fast events but ultimately
settled on a simple explanation: the stars 'burp' before exploding and do
not generate enough radioactive energy to be seen later. As the supernova
runs into the gas expelled in the burp, astrophysicists observe a flash.
The supernova then fades beyond their ability to detect it.
Astronomers conclude that this was a massive star that exploded, but it had
a mass loss -- a wind -- that started a couple of years before it exploded.
A shock ran into that wind after the explosion, and that is what caused the
big flash. But it turns out to have been a rather weak supernova, so within
a couple of weeks we did not see the rest of the light. The only visible
activity was from the quick collision of the gas and the exploding star,
where some of the kinetic energy was converted into light. One mystery that
remains is why the 'burp' would happen such a short time before the super-
nova explosion. Astrophysicists want to know how the outside of the star
reacts to what is happening deep in the core. While the Kepler telescope
and its K2 mission is expected to run out of fuel and end in the coming
months, NASA's Transiting Exoplanet Survey Satellite (TESS) is planned for
launch following the K2 mission. Data retrieved during the TESS mission
could also be used to study FELTs.

NASA/Goddard Space Flight Center

Astronomers using the Hubble Space Telescope have uncovered an ancient
'relic galaxy' in our own cosmic backyard. The very rare and odd assemblage
of stars has remained essentially unchanged for the past 10 billion
years and provides valuable new insights into the origin and evolution of
galaxies billions of years ago. The galaxy, NGC 1277, started its life with
a bang long ago, churning out stars a thousand times faster than happens
in our own Milky Way today. But it abruptly went quiescent as the early
stars aged and grew ever redder. Though Hubble has seen such 'red and dead'
galaxies in the early Universe, one has never been conclusively found
nearby. While the early galaxies are so distant, they are just red dots in
Hubble deep-sky images. NGC 1277 offers a unique opportunity to see one up
'close'. The researchers learned that the relic galaxy has twice as many
stars as our Milky Way, but physically it is only one quarter the size of
our galaxy. Essentially, NGC 1277 is in a state of 'arrested development'.
Perhaps, like all galaxies, it started out as a compact object but failed to
accrete more material to grow in size to form a pinwheel-shaped galaxy.
Researchers say that approximately one in 1,000 massive galaxies is expected
to be a relic galaxy like NGC 1277. They were not surprised to find it, but
simply consider that it was in the right place at the right time to evolve
-- or rather not evolve -- the way it did.
The telltale sign of the galaxy's state lies in the ancient globular
clusters of stars that swarm around it. Massive galaxies tend to have both
metal-poor (appearing blue) and metal-rich (appearing red) globular
clusters. The red clusters are believed to form as the galaxy forms, while
the blue clusters are later brought in as smaller satellites are swallowed
by the central galaxy. However, NGC 1277 is almost entirely lacking in blue
globular clusters. The red clusters are the strongest evidence that the
galaxy went out of the star-making business long ago. However, the lack of
blue clusters suggests that NGC 1277 never grew further by accreting
surrounding galaxies. By contrast, our Milky Way contains approximately 180
blue and red globular clusters. That is due partly to the fact that our
Milky Way continues cannibalizing galaxies that come too close by in our
Local Group of a few dozen small galaxies. It is a markedly different
environment for NGC 1277. That galaxy lives near the centre of the Perseus
cluster of over 1,000 galaxies, located 240 million light-years away. But
NGC 1277 is moving so fast through the cluster, at 2 million miles per hour,
that it cannot merge with other galaxies to collect stars or pull in gas to
fuel star formation. In addition, near the galaxy cluster centre, inter-
galactic gas is so hot that it cannot cool to condense and form stars.
The team started looking for 'arrested development' galaxies in the Sloan
Digital Sky Survey and found 50 candidate massive compact galaxies. Using a
similar technique, but from a different sample, NGC 1277 was identified as
unique in that it has a central black hole that is much more massive than it
should be for a galaxy of that size. That reinforces the scenario that the
supermassive black hole and dense hub of the galaxy grew simultaneously, but
the galaxy's stellar population stopped growing and expanding because it was
starved of outside material. The team has 10 other candidate galaxies to
look at with varying degrees of 'arrested development'.

University of California - Berkeley

Thanks to a rare cosmic alignment, astronomers have observed the most
distant normal star ever observed, some 9 billion light years away.
While astronomers routinely study galaxies much farther away, they are
visible only because they glow with the brightness of millions of stars.
And a supernova, often brighter than the galaxy in which it sits, also can
be visible across the entire Universe. In galaxies beyond a distance of
about 100 million light-years, however, the stars are impossible to make out
individually. But gravitational lensing -- the bending of light by massive
galaxy clusters in the line of sight -- can magnify the distant universe and
make dim and distant objects visible. Typically, lensing magnifies galaxies
by up to 50 times, but in this case, the star was magnified more than 2,000
times. It was discovered in Hubble telescope images taken in late April
2016. The discovery of the star, which astronomers often refer to as Icarus
rather than by its formal name, MACS J1149 Lensed Star 1 (LS1), initiates a
new technique for astronomers to study individual stars in galaxies formed
during the earliest days of the Universe. Such observations can provide a
rare look at how stars evolve, especially the most luminous ones. The
astronomy team also used Icarus to test and reject one theory of dark matter
-- that it consists of numerous primordial black holes lurking inside galaxy
clusters -- and to probe the make-up of normal matter and dark matter in the
galaxy cluster.
The star was noticed while the observers were monitoring a supernova that
they had discovered in 2014 while using Hubble to look through a
gravitational lens in the constellation Leo. That supernova, dubbed
SN Refsdal in honour of the late Norwegian astrophysicist Sjur Refsdal, a
pioneer of gravitational lensing studies, was split into four images by the
lens, a massive galaxy cluster called MACS J1149+2223, located about 5
billion light years away. Suspecting that Icarus might be more highly
magnified than SN Refsdal, astronomers analyzed the colours of the light
coming from it and discovered it was a single star, a blue supergiant. This
B-type star is much larger, more massive, hotter and possibly hundreds of
thousands of times intrinsically brighter than the Sun, though still much
too far away to see without the amplification of gravitational lensing. By
modelling the lens, they concluded that the tremendous apparent brightening
of Icarus was probably caused by a unique effect of gravitational lensing.
While an extended lens, like a galaxy cluster, can only magnify a background
object up to 50 times, smaller objects can magnify much more. A single star
in a foreground lens, if precisely aligned with a background star, can
magnify the background star thousands of times. In this case, a star about
the size of our Sun briefly passed directly through the line of sight
between the distant star Icarus and Hubble, boosting its brightness more
than 2,000 times. In fact, if the alignment was perfect, that single star
within the cluster turned the light from the distant star into an 'Einstein
ring' -- a halo of light created when light from the distant star bends
around all sides of the lensing star. The ring is too small to discern from
this distance, but the effect made the star easily visible by magnifying its
apparent brightness. The team saw a second star in the Hubble image, which
could either be a mirror image of Icarus, or a different star being gravi-
tationally lensed. There are analogous alignments all over the place as
background stars or stars in lensing galaxies move around, offering the
possibility of studying very distant stars dating from the early universe,
just as we have been using gravitational lensing to study distant galaxies.
For this type of research, nature has provided us with a larger telescope
than we can possibly build! As for Icarus, the astronomers predict that it
will be magnified many times over the next decade as cluster stars move
around, perhaps increasing its brightness as much as 10,000 times.


Astronomers are back in the dark about what dark matter might be, after new
observations showed that the mysterious substance may not be interacting
with forces other than gravity after all. Three years ago, a Durham-led
international team of researchers thought that they had made a breakthrough
in ultimately identifying what dark matter is. Observations from the
Hubble telescope appeared to show that a galaxy in the Abell 3827 cluster --
approximately 1.3 billion light-years away -- had become separated from
the dark matter surrounding it. Such an offset is predicted during
collisions if dark matter interacts with forces other than gravity,
potentially providing clues about what the substance might be. The chance
orientation at which the Abell 3827 cluster is seen from the Earth makes
it possible to conduct highly sensitive measurements of its dark matter.
However, the same group of astronomers now says that new data from more
recent observations show that dark matter in the Abell 3827 cluster has not
separated from its galaxy after all. The measurement is consistent with
dark matter feeling only the force of gravity.

The Universe is composed of approximately 27 per cent dark matter, with the
remainder largely consisting of the equally mysterious dark energy. Normal
matter, such as planets and stars, contributes a relatively small five per
cent of the Universe. There is believed to be about five times more dark
matter than all the other particles understood by science, but nobody knows
what it is. However, dark matter is an essential factor in how the Universe
looks today, as without the constraining effect of its extra gravity,
galaxies like our Milky Way would fling themselves apart as they spin. In
this latest study, the researchers used the Atacama Large Millimetre Array
(ALMA) in Chile to view the Abell 3827 cluster. ALMA picked up on the
distorted infra-red light from an unrelated background galaxy, revealing the
location of the otherwise invisible dark matter that remained unidentified
in the previous study. While the new results show dark matter staying with
its galaxy, the researchers said it did not necessarily mean that dark
matter does not interact. Dark matter might just interact very little, or
this particular galaxy might be moving directly towards us, so we would not
expect to see its dark matter displaced sideways, the team added. Several
new theories of non-standard dark matter have been invented over the past
two years and many have been simulated at Durham University with high-
powered computers. With a view to measuring the dark matter in hundreds of
galaxy clusters and continuing this investigation, Durham University has
just finished helping to build the new SuperBIT telescope, which gets a
clear view by rising above the Earth's atmosphere under a giant helium
Bulletin compiled by Clive Down
(c) 2018 The Society for Popular Astronomy

The Society for Popular Astronomy has been helping beginners in amateur
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Astronomy Group / The Night Sky in April
« on: April 04, 2018, 10:03:48 AM »

The Moon joins Jupiter, Mars, and Saturn in the early morning sky in early April, 2018

2-3 April.
Mars and Saturn are separated by less than 2 degrees, about the width of your thumb held at arm’s length. This month, Mars is slightly brighter and much redder than pale yellow Saturn. Mars will get brighter still and rival Jupiter by the end of July.

3-8 April.
Watch the waning Moon march eastward each night and pass three bright planets. The Moon moves through Libra and past Jupiter on the 3rd and 4th. Jupiter rises at about 11 p.m as April gets underway, and it shines brightly in the southern sky (or nearly overhead in the southern hemisphere) by about 3 a.m. By late in the first week of April, the Moon moves through Scorpius and into Sagittarius where Mars and Saturn rise in the east or southeast in the early morning hours. Jupiter, Saturn, and Mars will put on a splendid show in the coming months as they pass through opposition, one after the other, in May, June, and July, respectively.

8 April.
Moon Last Quarter Moon, 7:18 UTC

16 April.
New Moon, 1:57 UTC

18 April.
Saturn rises a little earlier each night as April progresses. It emerges above the southeastern horizon at 2:30 a.m. at the beginning of the month and at 12:45 a.m. by the end. And today, the planet reaches aphelion, its furthest position from the Sun in its orbit and its furthest aphelion since 1959.

18 April.
Look to the west, just after sunset, to spot a very slender crescent Moon. As darkness begins to fall, look also for the stars of the Hyades sprinkled around the Moon. The bright star Aldebaran is just a couple of degrees away. Binoculars will help you see this lovely arrangement.

22 April.
First Quarter Moon, 21:46 UTC

22 April.
The Lyrid meteor shower peaks tonight. Look for meteors that trace their apparent paths back to a point between the constellations Hercules and Lyra, both of which rise in the east around midnight. You can see these meteors at any time of night, from nearly anywhere on Earth, but you may have more luck after midnight as the Earth turns into the meteor stream and the first quarter Moon sets. The shower typically produces 15-20 meteors per hour, but some years have yielded surprise outbursts of several hundred per hour. The Lyrids, which have been observed for at least 2,500 years, originate as the Earth passes through a stream of debris left by Comet C/1861 G1 (Thatcher).

Venus lies between the Hyades and Pleiades star clusters on April 12, 2015.

24 April.
Look for brilliant Venus just two finger widths southeast of the Pleiades star cluster tonight. They appear in the western sky after sunset. Binoculars will help. In a telescope, the planet appears nearly fully lit. Venus shines at magnitude -3.9, brighter than anything else in the sky except for the Moon and Sun.

29 April.
Mercury, which was at inferior conjunction with the Sun at the beginning of the month, has speedily reached its greatest western elongation at 27º from the Sun. It appears in the morning sky before sunrise. From the northern hemisphere, the planet is just 10º above the horizon for this apparition. Observers in the southern hemisphere will enjoy a better view as the planet rises nearly 20º above the horizon well before sunrise.

30 April.
Full Moon, 00:58 UTC

30 April.
Look for the full Moon in Libra, near the bright planet Jupiter. The planet rises just half an hour after sunset as April comes to an end. It shines at a brilliant magnitude -2.5 and is now spectacular in a small telescope as it moves towards its closest approach to Earth on May 8. The planet is nearly 44” across.


Astronomy Group / Telescope for sale in Haverfordwest (Facebook ads)
« on: April 02, 2018, 11:33:21 AM »
If anyone is interested I can put you in touch with the seller!

General Chatty Stuff / One of our members in the news!
« on: March 29, 2018, 01:58:01 PM »
Janine swaps the Big Smoke for the quiet life..............

Janine Crooks, 56 from Narberth finds her perfect job thanks to EU Funded project Workways+. Janine, originally from London signed up to the Workways+ project after re-locating to Pembrokeshire 1 year ago. ....... For more information click here

The Cassini–Huygens mission, commonly called Cassini, was a collaboration between NASA, the European Space Agency, and the Italian Space Agency to send a probe to study the planet Saturn and its system, including its rings and natural satellites.
Launch mass: 5,712 kg (12,593 lb)
Dates: 15 Oct 1997 – 15 Sep 2017

Come and learn more about this stunningly successful mission.  Wednesday morning 28th March. 10.30 at Merlin's Bridge Welfare Hall.

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