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Thursday, 2 February 2012

SPA ENB No. 325

Electronic News Bulletin No. 325  2012 February 2

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
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By Richard Bailey, SPA Solar Section Director
Rotation Nos. 2117, 2118


Solar activity was good through the month, the NH being the stronger in the first half though no large AR's were seen in either hemisphere.  The first week had most individual sunspots.  It was noticeable that some NH AR's were nearer the equator than any in the SH. Faculae was regularly seen.

Week 1.   As at the end of last month,  AR's were spread across the NH, up to 5 being seen.  On the 2nd. from E to W were 1364, 65, 62, 61 and 58.  In the SH  AR1363 was halfway to the CM. By the 7th., SH AR's 67, 68 and 63 were astride the CM,  and 5 NH AR's across the disk with 1369 trailing.

Week 2.   A similar scene. On the 13th, NH AR1376 by the CM, others westward. SH AR1374 by the CM.

Week 3.   Stronger activity in the SH than in the NH from the 18th, Up to 5 across the disk there on the 20th. NH AR1384 was the best AR of the month, having a large leader and good followers.

Week 4 to the end of the month. The SH continued its activity, On the 29th. 4 AR's showed from E to W, AR 1386, a sprinkling of small spots was by the CM,
1389 just in from the E, 1387 by the W limb and two NH AR's,  fading 1384 followed by small 1390.

MDF   5.36       R   54,32


Good sized and varied prominences were  seen regularly  around the disk some being visible for a few days with changed appearances.  A fine arched  one stood out in the NW on the 12th,   A quickly erupting prominence on the 3rd in the NE , another on the 17th. in the NW around 1100UT  achieved good heights.   An intensely bright flare was observed in the E on the  31st at 1310UT,
Filaments were regularly seen.   In Week 2 extended filaments were observed across the NH,  NH AR1384 had good plaging and filament activity.

MDF    4.36

This Solar report is an edited version. The full report, which includes a selection of the fine pictures sent in by Section members, can be viewed on the SPA homepage in the Solar section under monthly reports.


NASA's twin Gravity Recovery And Interior Laboratory (GRAIL) probes successfully entered lunar orbit over New Years. GRAIL-A, which has just been renamed to Ebb, arrived at its destination on New Years Eve and GRAIL-B, now called Flow, followed 25 hours later on New Years Day. The names Ebb and Flow were chosen due to the effect that the Moon's gravity has on the Earth's tides, and the names were the result of a competition for schools in the USA to name the two probes. The science phase of the mission will begin in March, and in the mean time the twins will be spiralling down to their desired orbit. Once there, they will begin to map the lunar gravity by measuring the varying distance between the craft as Flow follows Ebb around the Moon. If there is a large mass on the surface or in the interior, then Flow will accelerate towards it, temporarily leaving Ebb behind. Soon Ebb will catch up, and it is distances between the craft that allow the gravity beneath them to be
measured.  A gravity map will reveal secrets of the lunar interior, as well enabling scientists to measure the Moon's tides. Just as the Moon creates tides on Earth, the Earth also creates 9 centimetre bulges in the lunar


SpaceX's Dragon test flight, which was due to occur on 7 February, has been delayed. The delay is due to the fact that further work is needed on the craft before SpaceX will be happy to launch it.  The Dragon capsule has already been tested in orbit, and was launched by SpaceX's own Falcon 9 rocket. However this test flight will go one step further and the craft will dock with the International Space Station. If successful, it will show that private companies have the ability to send supplies to the space station. It is hoped that eventually Dragon will also be able to bring people to the ISS. The capsule could still be launched by the end of February, but it is possible that it could be delayed up until April.


To date over 700 exoplanets have been discovered, but recent calculations show that there should be at least 100 billion planets in the Milky Way. Most of those planets have been discovered by detecting the stars wobble due to the planet, known as radial velocity, or by the periodic dimming of the star as the planet passes in front of it, known as transiting. However thirteen planets have been discovered via a technique known as microlensing. Microlensing relies on a phenomenon predicted by Albert Einstein in which light bends around massive objects. As light from a distant star, known as the source, bends around a foreground star, known as the lens, we see an increase in light as the source star is magnified by the "lens". This magnification allows any planets around the lens star to be detected as a bump or a dip on the light curve. These events are incredibly rare, as the Earth, lens and source star need to be lined up perfectly. The fact that thirteen planets have been
detected via this method either implies that planets are very common in the Galaxy, with an average of 1.6 planets per

By Andrew Robertson, Planetary Section Director

Jupiter, the King of the planets is slowly coming to the end of an excellent
apparition. At the end of January it culminates (reaches it's highest
position due south) at 1716 hours at an altitude of 49 degrees. The sun sets just after 4.30pm but astronomical dark doesn't begin until about 6.30pm. I
find twilight one of the best times to observe the planets as the atmosphere
can be particularly steady during this period which at the moment coincides
with Jupiter being reasonably high in the sky. It still presents a
reasonable angular diameter of 39" and I've been getting some
excellent views of it from as early as 4.30pm. By 10pm Jupiter is low down
in the West at an altitude of only 20 degrees. Seeing will be poor at this
altitude so the window of good opportunity is reducing. By the end of
February it culminates just after 3.30pm whereas the sun doesn't set until
5.30pm with Jupiter descending to 20 degrees altitude by 8.30pm. It's worth
grabbing a look when you can - there are always things happening with
Jupiter. Currently the North Equatorial Belt (NEB) seems to be getting
thinner and the Great Red Spot (GRS) is fading in colour. Also there are
always transits and occultations of its moons taking place, a glorious
spectacle to watch.

Venus currently shines like a beacon at magnitude -4.1 in the SSW at an
altitude of 27 degrees as the sun sets. It's 15" in diameter and displaying
a 75% gibbous phase. By the end of February at sunset Venus will have risen
to 37 degrees altitude in the SW displaying a diameter of 18" and a phase of

Mars is coming to prominence as it approaches it's opposition on 3rd March.
It exceeded 10" in diameter on 12th January and will remain above this
diameter until 29th April. I always consider 10" diameter the size at which
reasonable detail can be observed visually. It's currently 11.6" in diameter
culminating at 3am at an altitude of 44 degrees. It's also showing a phase
of 96% which is readily detectable visually. But it's at an altitude of 20
degrees by 2230 hrs so you should be able to start getting reasonable views
from about 11pm. Visually a prominent North polar cap is on view and you can
readily observe it's main dark features such as Syrtis Major in a moderate
aperture telescope. By the end of February it culminates at 0030 hours at an
altitude of 47 degrees showing a full disc and displaying an angular
diameter of almost 14". Remember, Mars only comes to opposition about every
2 years and 2 months so it's worth making the most of this opportunity.

Saturn is now rising in the early hours reaching 20 degrees altitude in the
SE by 2.30am. It culminates at 5am at an altitude of 28 degrees. Saturn is
well south of the celestial equator now (declination is currently -9
degrees) and it's only going to get worse over the next few years.

Good observing and please submit any observing reports to me via the
planetary section web site.

Bulletin compiled by Amanda Doyle


Good Clear Skies
Colin James Watling
Various Voluntary work-Litter Picking for Parish Council (Daytime) and also a friend of Kessingland Beach (Watchman)
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)
Information -- More Info -- And More Info

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