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| The pulse of the Sun's dynamo |
| Currents of gas deep inside the Sun pulsate like the blood in human arteries, speeding and slackening every 16 months. Solar scientists are astonished by this discovery. It comes from an international team pooling observations from the MDI instrument on the ESA-NASA SOHO spacecraft and from a worldwide chain of ground stations called GONG. Rachel Howe and her colleagues announce their results in the 31 March issue
of the journal Science.
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| Date: 03 Apr 2000 |
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| The best of SOHO on a CD-Rom |
| Stunning images and movies of the stormy Sun are included in ESA's new
CD-ROM "SOHO: Exploring the Sun". The material comes from four years'
observations of the Sun by the ESA-NASA SOHO spacecraft since its launch
at the end of 1995. The CD-ROM is organized by subjects in an easy-to-use format.
Nearly 200,000 copies are being distributed to the readers
of several astronomy and space magazines, with the April 2000 issues of
Astronomy Now (United Kingdom) and Orione (Italy), and the May issues
of Ciel et Espace (France) and Sterne und Weltraum (Germany).
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| Date: 17 Mar 2000 |
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| INFO 05-2000: SOHO sees right through the Sun |
| One of the highest hopes for SOHO, the European Space Agency (ESA)-NASA spacecraft is fulfilled with the detection of sunspots on the invisible far side of the Sun. This scientific marvel promises practical benefits. It could give an extra week's warning of possible bad weather in space, to astronauts and operators of satellites, power networks and other systems liable to be affected by eruptions on the Sun linked to sunspots. |
| Date: 09 Mar 2000 |
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| Dublin Concert is out of this world |
| An interest in space exploration is frequently considered to be the preserve of scientists, but, as a concert last night demonstrated, this is not necessarily the case. A packed audience at St Patricks College, Maynooth, near Dublin, enjoyed a unique aesthetic experience in which space science and music were intertwined. |
| Date: 06 Mar 2000 |
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| A debate on the Sun's role in global warming |
| Discoveries about how the Sun may affect the Earth's climate will be
discussed on the Spanish island of Tenerife, 25-30 September 2000. The
leading hypothesis in climate science is that most of the warming during
the 20th Century was due to manmade gases, enhancing the natural
greenhouse effect that reduces heat loss into space. Behind the scenes,
and especially among space scientists, there is renewed attention to
natural changes in climate due to the Sun. |
| Date: 01 Mar 2000 |
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| A good weekend for aurora watchers? |
| At 22:30 Central European Time on 17 February the ESA-NASA SOHO spacecraft spotted a large puff of gas from the Sun. Subsequent images from the LASCO coronagraph on SOHO confirmed that this coronal mass ejection is heading towards the Earth. The gas will reach the Earth's vicinity on Saturday or Sunday, 19 or 20 February. When it hits the Earth's magnetic shield, it is likely to cause a magnetic storm. It may provoke spectacular displays of auroras high in the air over sub-polar regions of the Earth, and perhaps even at lower latitudes in Scandinavia and North America. |
| Date: 18 Feb 2000 |
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| INFO 02-2000: 100 and Counting - SOHO's score as the world's top comet finder |
| Calculations completed today confirm that a comet spotted by a Lithuanian astronomer on 4 February is a previously unknown object, making it the 100th comet discovered with the SOHO spacecraft. Launched four years ago as a project of international cooperation between the
European Space Agency and NASA, the Solar and Heliospheric Observatory
has revolutionized the science of the Sun. It has also revealed an
amazing number of kamikaze comets plunging into the solar atmosphere, which help to make SOHO the most prolific comet finder in the history of astronomy. But SOHO-100 is an ordinary comet, and so are two others that have appeared in the past few days. |
| Date: 08 Feb 2000 |
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| SOHO shows magnificant solar fireworks |
| Over the weekend of 8-10 January, a fortunate turn of events enabled the SOHO/EIT instrument to capture a magnificant solar firework display. Spectacular movies and high-resolution images are available on the SOHO hot shots page. |
| Date: 28 Jan 2000 |
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| SOHO is ready again to warn of solar storms |
| With the Sun now entering its season of maximum sunspot counts, the
world's engineers have reason to be nervous. Blustery space weather
stirred up by the Sun can disrupt technological systems on the Earth and
especially in orbit, where 75 communications satellites worth about 15
billion euros are at risk from solar storms. So the engineers will be
glad to know that the world's chief watchdog for the Sun, the ESA-NASA
SOHO spacecraft, is now fully back on duty after a technical
interruption from 28 November to 10 December that curtailed some of its
observations.
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| Date: 15 Dec 1999 |
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| SOHO back to normal operations |
| While the spaceworld has had its eyes on the successful launch of ESA's XMM telescope, SOHO recovery teams have been busy at GSFC. As of 10 December at 01:00 UT, the SOHO spacecraft is back in Normal Mode.
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| Date: 10 Dec 1999 |
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| SOHO set for a return to normal operations |
| SOHO is performing maneuvres in preparation for a return to
Normal Mode this evening. All instruments are in a safe
configuration for the maneuvres.
Yesterday, a momentum management was performed prior to a
roll back to the nominal pointing position. The spacecraft was left in
Roll Maneuvre Wheels mode for the night.
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| Date: 09 Dec 1999 |
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| SOHO prepares to return to normal operations |
| Today and tomorrow, SOHO will be performing maneuvres in preparation
for a return to Normal Mode tomorrow evening. All instruments are in
a safe configuration for the maneuvres.
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| Date: 08 Dec 1999 |
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| SOHO in CRP mode until 8 December |
| SOHO is in Coarse Roll Pointing (CRP) mode at a roll angle of -76
degrees. The current plan is to leave the spacecraft in that
configuration until Wednesday 8 December. Some instruments (MDI, EIT,
LASCO and SWAN) are performing observations with some precautionary procedures (so-called 'safing flags') in place. |
| Date: 06 Dec 1999 |
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| SOHO back out of ESR |
| As of Thursday 2 December, 19:42 UT, SOHO is no longer in Emergency Sun Reacquisition (ESR) mode, after a successful transition to Coarse
Roll Pointing (CRP) mode.
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| Date: 02 Dec 1999 |
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| SOHO recovery actions continue |
| On Tuesday 1 December at 18:46 UT another SOHO spacecraft
emergency was declared in order to secure Deep Space Network (DSN) contact with 34-metre antennas, after a
manual triggering of the Emergency Sun Reacquisition (ESR) mode at about 18:40 UT.
At about 18:10 UT, SOHO was in the middle of a
stationkeeping (orbit trim) manoeuvre
Roll Pointing (CRP) mode was invoked automatically and the thruster burns were aborted. The cause of this anomaly is yet to be determined. |
| Date: 02 Dec 1999 |
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| SOHO ESR ends |
| As of Monday 29 November, 18:35 UT, SOHO is no longer in Emergency Sun
Reacquisition (ESR) mode. The SOHO spacecraft emergency that was declared
to ensure adequate Deep Space Network (DSN) coverage has officially
ended. Instruments are in safe configuration and appear to be
unscathed from the episode.
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| Date: 01 Dec 1999 |
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| SOHO recovery continues |
| Recovery of the SOHO spacecraft to normal science operations is proceeding with maneuvres to compensate for
stay of about 21 hours in ESR mode, which perturbed the angular
momentum, orbit and roll of the spacecraft. |
| Date: 01 Dec 1999 |
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| SOHO in safe mode |
| Over the Thanksgiving weekend the joint ESA/NASA SOHO recovery team stepped into action once again when the SOHO spacecraft switched to Emergency Sun Reacquisition mode(ESR) on Sunday 28 November. ESR is the safe mode that is automatically triggered to protect the spacecraft in the event of any unforeseen circumstance. |
| Date: 29 Nov 1999 |
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| SOHO sees the Mercury transit |
| This Extreme Ultraviolet Imaging Telescope (EIT) image shows the planet Mercury passing in front of the solar corona on 15 November 1999, as seen from the Solar and Heliospheric Observatory (SOHO). The planet is seen as a featureless dark spot just above the solar disk.
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| Date: 23 Nov 1999 |
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| SOHO prepares to weather the Leonid's meteor storm |
| The Earth will have another close encounter with Comet Tempel-Tuttle's dust trail in the early hours of 18 November, and the resulting meteor storm, called the Leonids, could be spectacular.
But the storm so eagerly awaited by astronomers is also making spacecraft controllers take precautions. Like a ship caught in a tempest, ESA's Solar and Heliospheric Observatory (SOHO) will try to stay as safe as possible during the meteor storm. |
| Date: 11 Nov 1999 |
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