***********************************
The SOCIETY for POPULAR ASTRONOMY
***********************************
====================================================
Electronic News Bulletin No. 288 2010 May 16
====================================================
Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is 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 http://www.popastro.com/
Astronomica is sponsoring the SPA Electronic News Bulletin.
LYRIDS
By Alastair McBeath, SPA Meteor Section Director
As discussed in ENB 286 (archived at: http://snipurl.com/w9p9b ), the
Lyrid maximum was due on April 22 this year, sometime between
09h-21h UT. Indications are the highest Zenithal Hourly Rate (ZHR)
reached ~20 +/- 4, so roughly normal, around 17:00-21:30 UT that
evening, judging by the International Meteor Organization's (IMO's) "live"
Lyrids page, at: http://www.imo.net/live/lyrids2010/ , detected despite the
late-setting waxing gibbous Moon (which set only after the start of
morning twilight for much of Britain).
Disappointingly few people were able to report-in positively from the
shower to the SPA. British sky conditions seem to have been their usual
frustrating mixture, and things elsewhere were not ideal. There are some
notes on how some people fared in parts of Britain on the UK Weather
World's Space Weather Forum for example, at: http://snipurl.com/wa0tw .
The IMO-reported maximum's timing was very poor for Europe and
North America, from where most SPA contributors typically observe.
European observations reaching the Section directly, including those from
the UK, suggested activity around 00h-03h UT on April 21-22 was
around 10 +/- 3, perhaps a little higher towards dawn. Although based
on very few results, this was in-line with the IMO's preliminary findings.
Examining the data in Radio Meteor Observation Bulletin 201 (for April
2010; see: http://www.rmob.org ) showed little clear sign of the Lyrids
this time, hardly surprising for the European systems especially, given that
the shower's radiant was about at its lowest elevation for the day, or
indeed below the horizon for some, during the probable peak. Western
North American observers had somewhat better conditions initially then,
but with a declining to setting radiant generally. However, a majority of
North American systems did find distinctly elevated echo counts from
roughly 12h-15h UT, plus-or-minus an hour at either end of this interval,
likely part of the rising activity towards the Lyrid maximum. One or two
European systems suggested modestly enhanced activity above normal
from about 04h-10h UT that day, which was perhaps still present through
to around 04h-05h UT on April 23, though this was inconclusive as so
few systems detected it. One far-west North American set-up recorded
a notably stronger peak from 18h-20h UT on the 22nd, nicely in-time to
the visual findings at least, if again unconfirmed elsewhere.
Our contributing observers active over the Lyrid epoch were as follows,
including information from the North American Meteor Network
(NAMN; see http://www.namnmeteors.org ), kindly provided by
Network leader Mark Davis, and RMOB 201 helpfully submitted by
editor Chris Steyaert. In the list, "R" means radio and "V" visual results
came from that individual:
Salvador Aguirre (Mexico; NAMN; V), Enric Algeciras (Spain; RMOB;
R), Orlando Benitez (Canary Islands; RMOB; R), Michael Boschat
(Nova Scotia, Canada; RMOB; R), Jeff Brower (British Columbia,
Canada; R; some data also in RMOB), Willy Camps (Belgium; RMOB;
R), Johan Coussens (Belgium; RMOB; R), Gaspard De Wilde (Belgium;
RMOB; R), John Drummond (New Zealand; NAMN; V), Franky
Dubois (Belgium; RMOB; R), David Entwistle (England; RMOB; R),
Kurt Fisher (Utah, USA; RMOB; R), Karl-Heinz Gansel (Germany;
RMOB; R), Dave Hancox (Scotland; V), Ken Hodonsky (Illinois, USA;
NAMN; V), Conor McDonald (Northern Ireland; V), Mike Otte
(Illinois, USA; RMOB; R), Jürgen Rendtel (Germany; V), Steve Roush
(Arizona, USA; RMOB; R), Wayne Sanders (British Columbia, Canada;
RMOB; R), Andy Smith (England; RMOB; R), Chris Steyaert (Belgium;
RMOB; R), Dave Swan (England; RMOB; R), Rich Taibi (Maryland,
USA; V), Istvan Tepliczky (Hungary; RMOB; R), Felix Verbelen
(Belgium; RMOB; R).
Many thanks go to everyone involved for their efforts, and commiserations
to those who were unlucky with the weather. Any additional Lyrid results
would be most welcome!
APRIL FIREBALLS UPDATE
By Alastair McBeath, SPA Meteor Section Director
As regular followers of the Section's webpages may be aware, there have
been problems and delays in updating the "Recent Fireball Sightings" page
in recent weeks (at: http://snipurl.com/w9p6d ). The notes here
summarize the fresh information received on already-reported British
fireballs, and new events, since ENB 287.
A third observation of the magnitude -10 or so fireball at 20:15 +/- 5
minutes UT on April 9-10 has arrived, from the western Highlands of
Scotland. The estimated possible overflight zone for the object is still as
reported in ENB 287, however.
Several additional sightings have come in from April 16-17, but not all
were of the very bright, green fireball seen near 22:00 UT. New sightings
of that meteor have arrived from Kent and western France, bringing the
total to six, although without refining the possible area of its occurrence as
yet. The extra events included: a magnitude -5 meteor seen to the
northwest, heading north from Kent, at some time probably between
21:30-21:45 UT; another bright green meteor, which was also close to
22:00 UT, but observed to the east-southeast from Norfolk, meaning it
must have been a different meteor to the multiple-observer event near the
same time; and a third bright green fireball near 23:55 UT, as spotted
from Hertfordshire. Preliminary notes on this latter event can be found on
the SPA's Observing Forum topic for the ~22h UT meteor, at:
http://snipurl.com/wagm0 .
April 17-18 brought another bright, green-white fireball for a lucky
witness in Gloucestershire around 23:00 UT, followed by a magnitude -3
meteor at about 22:00 UT on April 23-24, as seen from Suffolk. Notes
on this fireball also can be found among the comments regarding the
April 16-17 fireballs on the Observing Forum.
April 27-28 produced a very bright meteor within ten minutes of
20:15 UT, as witnessed from three sites in southern England - Kent,
Wiltshire and Shropshire. The Shropshire observer indicated a probably-
associated sonic boom had been heard as well, while the other viewers
noted the object had fragmented during its flight. No information
regarding its possible trajectory is yet available, but if the sonic boom was
linked to the meteor, it may have passed over or near southern Shropshire.
More news has come from the USA regarding the April 14 Midwestern
fireball as well, commented upon last time. Regular Section contributor
and correspondent Jeff Brower in southwestern Canada noted it was
featuring almost nightly on the TV news there, and that 2.3 kg of
meteorites had been recovered by April 26, the first just a day after the
fireball flew over. The timing has been refined to 22:07 local, 03:07 UT,
while the observer tally has continued to grow, with the American
Meteor Society's fireball webpage (off the http://www.amsmeteors.org
homepage ) indicating it was seen from twelve states across the American
Midwest and Great Lakes regions. Witnesses in Wisconsin and Iowa
heard sonic booms as the object detonated, showering Wisconsin with
meteorites in and near the town of Livingston. Numerous additional video
recordings have been collected since the ENB 287 notes, many from
security cameras, catching the late flight. The meteorites were detected
by weather radar during their lower-atmosphere flight too. (Additional
notes on this meteor were from the April issue of the IMO's journal
WGN, Vol. 38, No. 2, p. 49, in the Editorial by Javor Kac.)
Observations of fireballs (meteors of magnitude -3 and brighter) seen
from the British Isles and places nearby are always welcomed by the
Meteor Section. For advice on what information to send (including an
e-mail report form), see the "Making and Reporting Fireball Observations"
page of the SPA website, at: http://snipurl.com/u8aer .
LUNAR FEATURE OF THE MONTH - MAY 2010
By Peter Grego, SPA Lunar Section Director
A mighty cliff: Rupes Recta, the 'Straight Wall'
On 21 May the Moon's sunrise terminator rolls back to reveal a
remarkable feature near the southeastern shore of Mare Nubium (the
Sea of Clouds) -- one of the Moon's most magnificent cliffs, Rupes
Recta, the so-called 'Straight Wall', a feature caused by crustal faulting.
Tension in the Moon's crust following the cooling of the lavas which filled
Mare Nubium around three billion years ago pulled the crust apart. The
crust eventually cracked under such stresses, and the force of gravity
produced a horizontal displacement between the two separated blocks
of crust, the crust in the west dropping down relative to the eastern side
of the fault; the exposed edge is a cliff known as a fault scarp.
Rupes Recta is by far the best example of a normal fault on the Moon.
The fault scarp has a rather gentle gradient of around seven degrees and
runs north south for 126 km from the Stag's Horn Mountains to the
small crater Birt D, in a very slight curve. The Straight Wall is best seen
just after First Quarter phase, as on 21 May, when it throws a prominent
broad shadow westward onto the relatively flat mare floor, so bold as to
be easily visible through binoculars. The cliff's shadow gradually recedes
over the next day or two and is virtually invisible at high illuminations
when no shadows are cast. However, around Last Quarter phase as the
evening terminator approaches Mare Nubium, the cliff face brightens and
shows up clearly as a bright narrow line. 35km west of Rupes Recta,
and lying parallel to it, is a narrow cleft – a channel carved by running
lava -- known as Rima Birt which connects the small craters Birt E and
Birt F. An 80mm refractor will just about resolve Rima Birt on a fine night
and under favourable conditions of illumination.
PLANETS
By Andrew Robertson, SPA Planetary Section Director
VENUS is now moderately high in the west after the Sun has set. You
can't miss this beacon of our skies. A thin crescent Moon joins the
scene on Sunday evening.
MARS is still a very noticeable red at mag +0.9 on the borders of
Cancer & Leo, but at less than 7" diameter little can be seen on its
surface, although you may notice its phase of 90% if a high power is
used.
SATURN is well past opposition now but still fairly high in the south
just after sunset. Its rings are at about their narrowest of 2
degrees at present. In subsequent years they will start widening
again, so it is worth having a look at in this rare view. It is
feasible to see transits of its moons when the rings are close to
edge-on. The easiest to see are Titan's but none is visible from the
UK this apparition. The next easiest are Rhea, Dione and Tethys, but
you will need a moderate to large telescope (preferably optimised for
high contrast) and excellent seeing, when you may glimpse a shadow
transit. Seeing the actual moons themselves in transit is very
doubtful.
JUPITER is a morning object, rising just before 3.30am BST, but by the
time the Sun has risen (5am) it has only reached an altitude of 15
degrees. However, Jupiter's South Equatorial belt has disappeared, so
it has an unfamiliar look about it, so worth trying to get a view if
you can.
ICE FOUND ON ASTEROID
NASA
Scientists have detected water-ice and carbon-containing compounds on
the surface of an asteroid. A seemingly sweeping generalisation from
the discovery of those substances on *one* large asteroid has resulted
in a suggestion that some asteroids, along with comets, were the water
carriers for the primordial Earth. The discovery is a result of seven
observations, the first of which was made in 2002, of asteroid 24
Themis by astronomers who were using an infrared telescope. The
findings are surprising because it was believed that Themis, orbiting
at 479 million kilometres, was too close to the Sun to carry ice left
over from the Solar System's origin 4.6 billion years ago.
GALACTIC STAR FORMATION IS SLOWING
ESA
Astronomers using the Herschel infrared telescope have shown that the
formation of new stars in galaxies like the Milky Way has declined
fivefold in the last three billion years. Observing in the infrared
has allowed scientists to see galaxies, mainly spiral ones like the
Milky Way, that were previously hidden from view by cosmic dust
clouds. The Herschel telescope, launched a year ago to study star
formation, is the biggest ever sent into space, and is orbiting at a
distance of 1.5 million kilometres from the Earth.
BLACK HOLE THROWN OUT OF GALAXY
RAS
Astronomers who have been comparing positional catalogues of X-ray
sources and of galaxies have found what appears to be a super-massive
black hole leaving its home galaxy at high speed. The material that
falls into black holes heats up dramatically on its final journey and
often causes black holes to be strong X-ray sources. X-rays are also
able to penetrate the dust and gas that obscures the centre of a
galaxy, giving astronomers a clear view of the region around the black
hole, with the bright source appearing as a starlike point. Looking
at one galaxy in the catalogue, researchers noticed that the point of
light was offset from the centre and yet was so bright that it could
well be associated with a super-massive black hole. The black hole
appears to be in the process of being expelled from its galaxy at high
speed. Since such objects can have masses equivalent to 1 billion
Suns, it takes a special set of conditions to cause that to happen.
It is being speculated that the newly-discovered object may have
resulted from the merger of two smaller black holes. Models suggest
that the merged hole that results is shot out at a high speed, that
depends on the direction and speed at which the two black holes rotate
before their collision.
MOST DISTANT CLUSTER OF GALAXIES
IPMU, Japan
Galaxies seem not to be uniformly distributed in the Universe, but to
be arrayed in filamentary structures that form a gigantic cosmic
spider web. Clusters of galaxies are often located at knots in the
filaments. The most distant cluster known until now is about 9.2
billion light-years away.
The expansion of the universe shifts the light of distant objects
away from visible wavelengths, towards the infrared. Observing in the
infrared may therefore enable astronomers to see more distant
objects. On the other hand, clusters of galaxies tend to contain a lot
of matter heated to extreme temperatures, at which the emitted light
is of such short wavelengths that even despite the redshift it appears
as X-rays.
A team of astronomers from Japan and Germany has used an infrared
camera on the Japanese Subaru telescope in Hawaii to discover the most
distant cluster of galaxies observed up to the present, 9.6 billion
light-years away. The team also used the orbiting X-ray observatory
XMM-Newton, and detected a clear signature of hot gas in the cluster.
ENGINEERS WORKING ON VOYAGER 2 DATA SYSTEM
ScienceDaily
Engineers have shifted the Voyager 2 spacecraft into a mode that
transmits only spacecraft health and status data while they try to
correct an unexpected change in the pattern of returning data.
Preliminary engineering data received on May 1 show that the
spacecraft is basically healthy, and that the trouble is with the
flight data system, which formats the data to send back to Earth. The
first changes in the return of data packets from Voyager 2 appeared on
April 22. Engineers got their first chance to send commands to the
spacecraft on April 30. It takes nearly 13 hours for signals to reach
the spacecraft and the same for signals to come back to the Earth.
Voyager 2 was launched on 1977 August 20, about a fortnight before its
twin spacecraft, Voyager 1. The two spacecraft are the most distant
man-made objects, out at the edge of the heliosphere, the bubble that
the Sun creates around the Solar System. Voyager 2 is about 13.8
billion kilometres away, Voyager 1 about 16.9 billion kilometres.
Mission managers expect Voyager 1 to leave the Solar System and enter
interstellar space in the next five years or so, with Voyager 2 to
follow shortly after. Voyager 1 is in good health and performing
normally. Voyager 2's initial mission was a four-year journey to
Saturn, but as part of a mission extension it also flew past Uranus in
1986 and Neptune in 1989, taking advantage of a once-in-176-years
alignment to take a grand tour of the outer planets -- and it is still
returning data 33 years after launch.
(c) 2010 the Society for Popular Astronomy
The SOCIETY for POPULAR ASTRONOMY
***********************************
====================================================
Electronic News Bulletin No. 288 2010 May 16
====================================================
Here is the latest round-up of news from the Society for Popular
Astronomy. The SPA is 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 http://www.popastro.com/
Astronomica is sponsoring the SPA Electronic News Bulletin.
LYRIDS
By Alastair McBeath, SPA Meteor Section Director
As discussed in ENB 286 (archived at: http://snipurl.com/w9p9b ), the
Lyrid maximum was due on April 22 this year, sometime between
09h-21h UT. Indications are the highest Zenithal Hourly Rate (ZHR)
reached ~20 +/- 4, so roughly normal, around 17:00-21:30 UT that
evening, judging by the International Meteor Organization's (IMO's) "live"
Lyrids page, at: http://www.imo.net/live/lyrids2010/ , detected despite the
late-setting waxing gibbous Moon (which set only after the start of
morning twilight for much of Britain).
Disappointingly few people were able to report-in positively from the
shower to the SPA. British sky conditions seem to have been their usual
frustrating mixture, and things elsewhere were not ideal. There are some
notes on how some people fared in parts of Britain on the UK Weather
World's Space Weather Forum for example, at: http://snipurl.com/wa0tw .
The IMO-reported maximum's timing was very poor for Europe and
North America, from where most SPA contributors typically observe.
European observations reaching the Section directly, including those from
the UK, suggested activity around 00h-03h UT on April 21-22 was
around 10 +/- 3, perhaps a little higher towards dawn. Although based
on very few results, this was in-line with the IMO's preliminary findings.
Examining the data in Radio Meteor Observation Bulletin 201 (for April
2010; see: http://www.rmob.org ) showed little clear sign of the Lyrids
this time, hardly surprising for the European systems especially, given that
the shower's radiant was about at its lowest elevation for the day, or
indeed below the horizon for some, during the probable peak. Western
North American observers had somewhat better conditions initially then,
but with a declining to setting radiant generally. However, a majority of
North American systems did find distinctly elevated echo counts from
roughly 12h-15h UT, plus-or-minus an hour at either end of this interval,
likely part of the rising activity towards the Lyrid maximum. One or two
European systems suggested modestly enhanced activity above normal
from about 04h-10h UT that day, which was perhaps still present through
to around 04h-05h UT on April 23, though this was inconclusive as so
few systems detected it. One far-west North American set-up recorded
a notably stronger peak from 18h-20h UT on the 22nd, nicely in-time to
the visual findings at least, if again unconfirmed elsewhere.
Our contributing observers active over the Lyrid epoch were as follows,
including information from the North American Meteor Network
(NAMN; see http://www.namnmeteors.org ), kindly provided by
Network leader Mark Davis, and RMOB 201 helpfully submitted by
editor Chris Steyaert. In the list, "R" means radio and "V" visual results
came from that individual:
Salvador Aguirre (Mexico; NAMN; V), Enric Algeciras (Spain; RMOB;
R), Orlando Benitez (Canary Islands; RMOB; R), Michael Boschat
(Nova Scotia, Canada; RMOB; R), Jeff Brower (British Columbia,
Canada; R; some data also in RMOB), Willy Camps (Belgium; RMOB;
R), Johan Coussens (Belgium; RMOB; R), Gaspard De Wilde (Belgium;
RMOB; R), John Drummond (New Zealand; NAMN; V), Franky
Dubois (Belgium; RMOB; R), David Entwistle (England; RMOB; R),
Kurt Fisher (Utah, USA; RMOB; R), Karl-Heinz Gansel (Germany;
RMOB; R), Dave Hancox (Scotland; V), Ken Hodonsky (Illinois, USA;
NAMN; V), Conor McDonald (Northern Ireland; V), Mike Otte
(Illinois, USA; RMOB; R), Jürgen Rendtel (Germany; V), Steve Roush
(Arizona, USA; RMOB; R), Wayne Sanders (British Columbia, Canada;
RMOB; R), Andy Smith (England; RMOB; R), Chris Steyaert (Belgium;
RMOB; R), Dave Swan (England; RMOB; R), Rich Taibi (Maryland,
USA; V), Istvan Tepliczky (Hungary; RMOB; R), Felix Verbelen
(Belgium; RMOB; R).
Many thanks go to everyone involved for their efforts, and commiserations
to those who were unlucky with the weather. Any additional Lyrid results
would be most welcome!
APRIL FIREBALLS UPDATE
By Alastair McBeath, SPA Meteor Section Director
As regular followers of the Section's webpages may be aware, there have
been problems and delays in updating the "Recent Fireball Sightings" page
in recent weeks (at: http://snipurl.com/w9p6d ). The notes here
summarize the fresh information received on already-reported British
fireballs, and new events, since ENB 287.
A third observation of the magnitude -10 or so fireball at 20:15 +/- 5
minutes UT on April 9-10 has arrived, from the western Highlands of
Scotland. The estimated possible overflight zone for the object is still as
reported in ENB 287, however.
Several additional sightings have come in from April 16-17, but not all
were of the very bright, green fireball seen near 22:00 UT. New sightings
of that meteor have arrived from Kent and western France, bringing the
total to six, although without refining the possible area of its occurrence as
yet. The extra events included: a magnitude -5 meteor seen to the
northwest, heading north from Kent, at some time probably between
21:30-21:45 UT; another bright green meteor, which was also close to
22:00 UT, but observed to the east-southeast from Norfolk, meaning it
must have been a different meteor to the multiple-observer event near the
same time; and a third bright green fireball near 23:55 UT, as spotted
from Hertfordshire. Preliminary notes on this latter event can be found on
the SPA's Observing Forum topic for the ~22h UT meteor, at:
http://snipurl.com/wagm0 .
April 17-18 brought another bright, green-white fireball for a lucky
witness in Gloucestershire around 23:00 UT, followed by a magnitude -3
meteor at about 22:00 UT on April 23-24, as seen from Suffolk. Notes
on this fireball also can be found among the comments regarding the
April 16-17 fireballs on the Observing Forum.
April 27-28 produced a very bright meteor within ten minutes of
20:15 UT, as witnessed from three sites in southern England - Kent,
Wiltshire and Shropshire. The Shropshire observer indicated a probably-
associated sonic boom had been heard as well, while the other viewers
noted the object had fragmented during its flight. No information
regarding its possible trajectory is yet available, but if the sonic boom was
linked to the meteor, it may have passed over or near southern Shropshire.
More news has come from the USA regarding the April 14 Midwestern
fireball as well, commented upon last time. Regular Section contributor
and correspondent Jeff Brower in southwestern Canada noted it was
featuring almost nightly on the TV news there, and that 2.3 kg of
meteorites had been recovered by April 26, the first just a day after the
fireball flew over. The timing has been refined to 22:07 local, 03:07 UT,
while the observer tally has continued to grow, with the American
Meteor Society's fireball webpage (off the http://www.amsmeteors.org
homepage ) indicating it was seen from twelve states across the American
Midwest and Great Lakes regions. Witnesses in Wisconsin and Iowa
heard sonic booms as the object detonated, showering Wisconsin with
meteorites in and near the town of Livingston. Numerous additional video
recordings have been collected since the ENB 287 notes, many from
security cameras, catching the late flight. The meteorites were detected
by weather radar during their lower-atmosphere flight too. (Additional
notes on this meteor were from the April issue of the IMO's journal
WGN, Vol. 38, No. 2, p. 49, in the Editorial by Javor Kac.)
Observations of fireballs (meteors of magnitude -3 and brighter) seen
from the British Isles and places nearby are always welcomed by the
Meteor Section. For advice on what information to send (including an
e-mail report form), see the "Making and Reporting Fireball Observations"
page of the SPA website, at: http://snipurl.com/u8aer .
LUNAR FEATURE OF THE MONTH - MAY 2010
By Peter Grego, SPA Lunar Section Director
A mighty cliff: Rupes Recta, the 'Straight Wall'
On 21 May the Moon's sunrise terminator rolls back to reveal a
remarkable feature near the southeastern shore of Mare Nubium (the
Sea of Clouds) -- one of the Moon's most magnificent cliffs, Rupes
Recta, the so-called 'Straight Wall', a feature caused by crustal faulting.
Tension in the Moon's crust following the cooling of the lavas which filled
Mare Nubium around three billion years ago pulled the crust apart. The
crust eventually cracked under such stresses, and the force of gravity
produced a horizontal displacement between the two separated blocks
of crust, the crust in the west dropping down relative to the eastern side
of the fault; the exposed edge is a cliff known as a fault scarp.
Rupes Recta is by far the best example of a normal fault on the Moon.
The fault scarp has a rather gentle gradient of around seven degrees and
runs north south for 126 km from the Stag's Horn Mountains to the
small crater Birt D, in a very slight curve. The Straight Wall is best seen
just after First Quarter phase, as on 21 May, when it throws a prominent
broad shadow westward onto the relatively flat mare floor, so bold as to
be easily visible through binoculars. The cliff's shadow gradually recedes
over the next day or two and is virtually invisible at high illuminations
when no shadows are cast. However, around Last Quarter phase as the
evening terminator approaches Mare Nubium, the cliff face brightens and
shows up clearly as a bright narrow line. 35km west of Rupes Recta,
and lying parallel to it, is a narrow cleft – a channel carved by running
lava -- known as Rima Birt which connects the small craters Birt E and
Birt F. An 80mm refractor will just about resolve Rima Birt on a fine night
and under favourable conditions of illumination.
PLANETS
By Andrew Robertson, SPA Planetary Section Director
VENUS is now moderately high in the west after the Sun has set. You
can't miss this beacon of our skies. A thin crescent Moon joins the
scene on Sunday evening.
MARS is still a very noticeable red at mag +0.9 on the borders of
Cancer & Leo, but at less than 7" diameter little can be seen on its
surface, although you may notice its phase of 90% if a high power is
used.
SATURN is well past opposition now but still fairly high in the south
just after sunset. Its rings are at about their narrowest of 2
degrees at present. In subsequent years they will start widening
again, so it is worth having a look at in this rare view. It is
feasible to see transits of its moons when the rings are close to
edge-on. The easiest to see are Titan's but none is visible from the
UK this apparition. The next easiest are Rhea, Dione and Tethys, but
you will need a moderate to large telescope (preferably optimised for
high contrast) and excellent seeing, when you may glimpse a shadow
transit. Seeing the actual moons themselves in transit is very
doubtful.
JUPITER is a morning object, rising just before 3.30am BST, but by the
time the Sun has risen (5am) it has only reached an altitude of 15
degrees. However, Jupiter's South Equatorial belt has disappeared, so
it has an unfamiliar look about it, so worth trying to get a view if
you can.
ICE FOUND ON ASTEROID
NASA
Scientists have detected water-ice and carbon-containing compounds on
the surface of an asteroid. A seemingly sweeping generalisation from
the discovery of those substances on *one* large asteroid has resulted
in a suggestion that some asteroids, along with comets, were the water
carriers for the primordial Earth. The discovery is a result of seven
observations, the first of which was made in 2002, of asteroid 24
Themis by astronomers who were using an infrared telescope. The
findings are surprising because it was believed that Themis, orbiting
at 479 million kilometres, was too close to the Sun to carry ice left
over from the Solar System's origin 4.6 billion years ago.
GALACTIC STAR FORMATION IS SLOWING
ESA
Astronomers using the Herschel infrared telescope have shown that the
formation of new stars in galaxies like the Milky Way has declined
fivefold in the last three billion years. Observing in the infrared
has allowed scientists to see galaxies, mainly spiral ones like the
Milky Way, that were previously hidden from view by cosmic dust
clouds. The Herschel telescope, launched a year ago to study star
formation, is the biggest ever sent into space, and is orbiting at a
distance of 1.5 million kilometres from the Earth.
BLACK HOLE THROWN OUT OF GALAXY
RAS
Astronomers who have been comparing positional catalogues of X-ray
sources and of galaxies have found what appears to be a super-massive
black hole leaving its home galaxy at high speed. The material that
falls into black holes heats up dramatically on its final journey and
often causes black holes to be strong X-ray sources. X-rays are also
able to penetrate the dust and gas that obscures the centre of a
galaxy, giving astronomers a clear view of the region around the black
hole, with the bright source appearing as a starlike point. Looking
at one galaxy in the catalogue, researchers noticed that the point of
light was offset from the centre and yet was so bright that it could
well be associated with a super-massive black hole. The black hole
appears to be in the process of being expelled from its galaxy at high
speed. Since such objects can have masses equivalent to 1 billion
Suns, it takes a special set of conditions to cause that to happen.
It is being speculated that the newly-discovered object may have
resulted from the merger of two smaller black holes. Models suggest
that the merged hole that results is shot out at a high speed, that
depends on the direction and speed at which the two black holes rotate
before their collision.
MOST DISTANT CLUSTER OF GALAXIES
IPMU, Japan
Galaxies seem not to be uniformly distributed in the Universe, but to
be arrayed in filamentary structures that form a gigantic cosmic
spider web. Clusters of galaxies are often located at knots in the
filaments. The most distant cluster known until now is about 9.2
billion light-years away.
The expansion of the universe shifts the light of distant objects
away from visible wavelengths, towards the infrared. Observing in the
infrared may therefore enable astronomers to see more distant
objects. On the other hand, clusters of galaxies tend to contain a lot
of matter heated to extreme temperatures, at which the emitted light
is of such short wavelengths that even despite the redshift it appears
as X-rays.
A team of astronomers from Japan and Germany has used an infrared
camera on the Japanese Subaru telescope in Hawaii to discover the most
distant cluster of galaxies observed up to the present, 9.6 billion
light-years away. The team also used the orbiting X-ray observatory
XMM-Newton, and detected a clear signature of hot gas in the cluster.
ENGINEERS WORKING ON VOYAGER 2 DATA SYSTEM
ScienceDaily
Engineers have shifted the Voyager 2 spacecraft into a mode that
transmits only spacecraft health and status data while they try to
correct an unexpected change in the pattern of returning data.
Preliminary engineering data received on May 1 show that the
spacecraft is basically healthy, and that the trouble is with the
flight data system, which formats the data to send back to Earth. The
first changes in the return of data packets from Voyager 2 appeared on
April 22. Engineers got their first chance to send commands to the
spacecraft on April 30. It takes nearly 13 hours for signals to reach
the spacecraft and the same for signals to come back to the Earth.
Voyager 2 was launched on 1977 August 20, about a fortnight before its
twin spacecraft, Voyager 1. The two spacecraft are the most distant
man-made objects, out at the edge of the heliosphere, the bubble that
the Sun creates around the Solar System. Voyager 2 is about 13.8
billion kilometres away, Voyager 1 about 16.9 billion kilometres.
Mission managers expect Voyager 1 to leave the Solar System and enter
interstellar space in the next five years or so, with Voyager 2 to
follow shortly after. Voyager 1 is in good health and performing
normally. Voyager 2's initial mission was a four-year journey to
Saturn, but as part of a mission extension it also flew past Uranus in
1986 and Neptune in 1989, taking advantage of a once-in-176-years
alignment to take a grand tour of the outer planets -- and it is still
returning data 33 years after launch.
(c) 2010 the Society for Popular Astronomy
--
Good Clear Skies
--
Astrocomet
--
Colin James Watling
--
Profile: http://www.google.com/profiles/astrocomera
--
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
--
Web: http://lyra.freewebsites.com/
--
Information: http://www.clubbz.com/club/2895/LOWESTOFT---3054/Lowestoft%20And%20Great%20Yarmouth%20Regional%20Astronomers%20(Lyra
Good Clear Skies
--
Astrocomet
--
Colin James Watling
--
Profile: http://www.google.com/profiles/astrocomera
--
Real Astronomer and head of the Comet section for LYRA (Lowestoft and Great Yarmouth Regional Astronomers) also head of K.A.G (Kessingland Astronomy Group) and Navigator (Astrogator) of the Stars (Fieldwork)
--
Web: http://lyra.freewebsites.com/
--
Information: http://www.clubbz.com/club/2895/LOWESTOFT---3054/Lowestoft%20And%20Great%20Yarmouth%20Regional%20Astronomers%20(Lyra
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