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Friday 23 January 2009

Ring of Fire Solar Eclipse

Space Weather News for Jan. 23, 2007
http://spaceweather.com/

SOLAR ECLIPSE: On Monday, Jan. 26th, the Moon will pass in front of the sun producing an annular "ring of fire" eclipse. This is not a total eclipse; the Moon will cover only 93% of the sun's surface. Nevertheless, the Moon's dead-center transit across the solar disk will produce a sight of rare beauty for observers along the "path of annularity." Best views are to be had from islands in Indonesia where the ring of fire will appear to sink into the ocean at sunset. Meanwhile, in Australia, southeast Asia, southern parts of India and South Africa, observers will experience an off-center partial eclipse. Crescent-shaped sunbeams will dapple the ground while high overhead the Moon takes a curved bite out of the sun.

Please visit http://spaceweather.com/ for eclipse maps, timetables and photos.

BLUE-SKY FIREBALL: Last week a meteoroid of unknown size hit Earth's atmosphere over Denmark and exploded with a flash so bright it turned the nighttime sky daytime blue. A video of the remarkable fireball and eye-witness reports may be found at Spaceweather's fireball sighting page: http://spaceweather.com/glossary/fireballreports_17jan09.htm

Update on shuttle mission to Hubble / Satellite to track greenhouse gases

     NEWSALERT: Friday, January 23, 2009 @ 2021 GMT
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         The latest news from Spaceflight Now


++++ STS-119 crew patch: The next shuttle mission ++++
http://www.spaceflightnowstore.com


ONE LAUNCH PAD OR TWO? NO DECISION FOR HUBBLE MISSION
-----------------------------------------------------
NASA managers met Thursday and agreed to press ahead with plans to launch
the shuttle Atlantis as early as May 12 on a final mission to service and
upgrade the Hubble Space Telescope. But officials deferred a decision on
whether to require use of launch pad 39B for a potential emergency rescue
mission and what impact that would have on the Ares 1-X test flight
schedule.

 http://spaceflightnow.com/shuttle/sts125/090122pads/


JAPAN LAUNCHES SATELLITE TO TRACK GREENHOUSE GASES
--------------------------------------------------
The first satellite devoted to measuring greenhouse gases in Earth's
atmosphere arrived in space Friday after launching from an island
spaceport in southwestern Japan.

 http://spaceflightnow.com/h2a/gosat/


MOST RECENT SHUTTLE CREW PRESENTS ITS MISSION MOVIE
---------------------------------------------------
On cargo-delivery run to the space station in November, shuttle Endeavour
brought up critical equipment that remodeled the interior of the
international outpost in preparation for doubling the size of its resident
crews. The STS-126 astronauts recap their mission in this post-flight
video presentation.

 http://spaceflightnowplus.com/index.php?k=STS-126


HUBBLE SNAPS IMAGE OF A NEBULA WITHIN A CLUSTER
-----------------------------------------------
The Hubble Space Telescope has taken this picture of a unique planetary
nebula nested inside an open star cluster. Both the cluster and the nebula
reside over 10,000 light-years away, in the southern constellation Pyxis.

 http://spaceflightnow.com/news/n0901/21hubble/

C/2007 N3 Lulin...

Comet Lulin was still only about 11th or 12th magnitude when Michael Jaeger took this image on Sept. 2, 2008. He used an 8-inch f/2.8 ASA Astrograph with a SXV H9 CCD camera for this stacked pair of 4-minute exposures.

Comet C/2007 N3 (Lulin), discovered in July 2007, should be the highlight comet of this season. It's predicted to reach about 5th magnitude in late February, so it should be easily seen in binoculars. It may even become detectable with the unaided eye in a dark, moonless sky.

Below is a calendar of the comet's doings in the coming weeks (and here's an ephemeris). But don't assume that the brightnesses are trustworthy. The comet's brightness behavior may be unpredictable, because it's on a nearly parabolic orbit that suggests this is its first visit to the inner solar system. You never know what a pristine comet might do.

January: Pre-dawn, and Brightening

The comet spends January rapidly getting higher and brighter in the morning sky, as it moves westward from Libra into Virgo. The best time to look is just before the start of morning astronomical twilight. (To find this time for your location, make sure your location and time zone are up to date in our online almanac.)

The beginning of January found Comet Lulin glowing at 7th magnitude, not quite as bright as predicted. It was at perihelion (closest approach to the Sun) on January 10th, at a solar distance of 1.2 a.u. (181 million km). But rather than fading after perihelion, Lulin should brighten as its diminishing distance from us more than compensates for its moving away from the Sun.

Update Jan. 17: Mariano Ribas in Argentina writes: "Despite Moon interference, the comet right now is an easy target for amateur telescopes of 10 to 20 centimeters (4 to 8 inches) and big binoculars here in Buenos Aires, a city with strong light pollution (limiting magnitude about 4). Today, 1½ hours before sunrise, I saw the comet again and estimated its visual magnitude about 7.0, with a coma 3′ in diameter and moderately condensed (DC: 5/6). But no signs of tail."

Update Jan. 21: "Quite visible in 10x50 binocs in spite of the crescent Moon being close," reports Amar Sharma in Bangalore, India. "20x80 binocs gave a better view as a fuzzy globular, and the 8-inch scope did reveal a condensed fuzzy coma ~4-5 arcminutes in diameter."

Update Jan. 22: Still only about mag 6.8 or 7.0 according to reports, about 1 magnitude below predictions.

February: Peak Brightness, Peak Speed

As Comet Lulin nears Earth its speed across the sky will increase. The beginning of February sees the 6th- or 7th-magnitude comet rising around midnight, and it passes within 1° of the wide binocular double star Alpha Librae on the night of February 5–6. Initially moving at about 1° per day, Lulin will be creeping westward at 2° per day by February 11th, when it crosses into Virgo and passes within a quarter degree of Lambda Virginis.

Five days later, on the 16th, comet Lulin — now perhaps 5th or 6th magnitude — will pass 3° north of Spica, and the comet's speed will have increased to 3° per day.

On the night of February 23rd, near its peak brightness, Comet Lulin is passing 2° south-southwest of Saturn.

Lulin's closest approach to Earth, 0.41 a.u. (61 million km), occurs on February 24th, when the comet may reach a peak of magnitude 5. By now it's visible in late evening (after rising around the end of astronomical twilight) and remains in view for the rest of the night.

And it's speeding along at just over 5° per day! That's about 1 arcsecond every 5 seconds of time, enough to show obvious motion during a short telescopic observing session. Similarly, that's 1 arcminute per 5 minutes of time if you're using binoculars.

After that Lulin moves away from both Earth and the Sun, so it fades quickly. The evening of February 27 will see it at 5th or 6th magnitude within 1° of Regulus.

Weird Orbital Geometry

Strangely, as you may have noticed on the charts, this comet is traveling almost exactly along the ecliptic — backward! Could this really be just be a coincidence? The comet's nearly parabolic orbit indicates that it has never really interacted with the planets at all. Yet its orbital inclination is 178.4°, meaning that it's orbiting in the opposite direction from the planets just 1.6° from the ecliptic plane. (Manipulable 3-D orbit diagram).

Tails and Antitails

Because the comet stays nearly on the ecliptic, its tail (which points away from the Sun) aligns with the ecliptic and with the comet's own direction of motion across the sky. This is indicated by the direction the tail is pointed on the comet symbols on the finder charts linked to above.

Moreover, because Earth remains in the comet's own orbital plane, we're likely to see the comet with a very thin tail and an antitail, a spike pointing in almost the opposite direction from the main tail, for months on end. Why? In three dimensions a comet's dust tail is often wide but it's always thin, confined to the comet's orbital plane. When we are in or near this plane, we can sometimes see parts of the wide, thin dust tail on opposite sides of the comet's head. We pass through most comets' orbital planes briefly. But this time, the situation will last and last.

And indeed, as of January 7th Lulin did have an antitail, as shown in this image taken by Karzaman Ahmad in Malaysia with a 20-inch scope (image courtesy Spaceweather.com.) Here's another image, from Ernesto Guido, Giovanni Sostero and Paul Camilleri, taken January 8th. Here's an animation by Guido and Sostero showing the comet's motion between two images taken Jan. 16th and 17th, antitail and all. Here's a photo gallery of more.

A comet's blue-green gas tail, on the other hand, always points nearly in a straight line away from the Sun in space. Cometary gas is blown directly away from the Sun at high speed by the solar wind.

March: Following Lulin Out

Comet Lulin crosses from Leo into Cancer at the beginning of March. The night of March 5 sees the 6th-magnitude comet within 2° of both Delta (δ) Cancri and the Beehive Cluster (M44). It will make for a fine sight, particularly in high-powered binoculars. Think photo opportunity.

Another nice conjunction occurs on March 16th when the comet, now around 7th or 8th magnitude (and setting in the early hours of the morning), is 1° from Delta Geminorum.

As Comet Lulin recedes, its passage across our sky will slow. Indeed, from the end of March to the end of May (when Lulin may have faded to 11th magnitude) it will stay within a narrow, 3° strip of sky bounded by Epsilon (ε), Mu (μ), and 36 Geminorum.

Comet Lulin won't return again to the inner solar system for more than a thousand years.

Cooperative Discovery

Comet C/2007 N3 (Lulin) was discovered by Quanzhi Ye, a student (age 19) at Sun Yat-sen University in mainland China, as an apparently asteroidal object on images taken by Chi Sheng Lin (National Central University, Taiwan) with a 16-inch telescope at Lulin Observatory in Taiwan on the night of July 11, 2007. A week later, confirming images revealed the telltale presence of a coma. In China and Taiwan, the comet has been hailed as the "Comet of Cooperation."

Lulin was one of 223 comet discoveries on images taken from the ground and in space in 2007, an all-time record.

For a gallery of images and a light curve, check the Comet Lulin page on Seiichi Yoshida's Weekly Information about Bright Comets.
________________________________
Postscript: What Happened to Comet Boethin?

Another comet was expected to be visible in binoculars around this time: Periodic Comet 85P/Boethin. Discovered in 1975 by the late Rev. Leo Boethin (1912–98) in the Philippines, this comet orbits the Sun every 11 years. Or at least it used to.

Comet Boethin was recovered in 1985 and was predicted to brighten to no more than 12th magnitude during the winter of 1985–86 (when comet watchers were enjoying the buzz of Halley). However, it managed to surprise, reaching 7th magnitude in January 1986!

Did this outburst disrupt it completely? Comet Boethin was on track to return in 1997, but the poor circumstances of that return meant it could not be sighted. Nevertheless, astronomers decided in 2005 to redirect the Deep Impact spacecraft (now renamed the EPOXI mission) to study this comet, as its orbital path was ideal for the spacecraft.

In 2007 observers around the world and in space started searching for Comet Boethin, but to no avail. Not even a fragment has been found. Perhaps some tiny faint bit will be picked up by patrol telescopes in early 2009. But as of December 1, 2008, there was still no trace of it to 20th magnitude.

Fortunately, the EPOXI mission has now been redirected to the short-period comet 103P/Hartley 2. This one has been seen at four apparitions, so its orbit is secure.

This is not the first time that a periodic comet has been seen on two returns only to be lost. One example in the last century was 34D/Gale, discovered in 1927 from the inner suburbs of Sydney, Australia. It was recovered in 1938 but never seen again. Like Boethin, it too, coincidentally, had a period of 11 years.

Sky & Telescope.

Saturday 17 January 2009

More Comet Lulin

Comet Lulin was still only about 11th or 12th magnitude when Michael Jaeger took this image on Sept. 2, 2008. He used an 8-inch f/2.8 ASA Astrograph with a SXV H9 CCD camera for this stacked pair of 4-minute exposures.


Michael Jaeger Comet C/2007 N3 (Lulin), discovered in July 2007, should be the highlight comet of this season. It's predicted to reach about 5th magnitude in late February, so it should be easily seen in binoculars. It may even become detectable with the unaided eye in a dark, moonless sky.

Below is a calendar of the comet's doings in the coming weeks (and here's an ephemeris: http://www.cfa.harvard.edu/iau/Ephemerides/Comets/2007N3_1.html ). But don't assume that the brightnesses are trustworthy. The comet's brightness behavior may be unpredictable, because it's on a nearly parabolic orbit that suggests this is its first visit to the inner solar system. You never know what a pristine comet might do.

January: Pre-dawn, and Brightening


The start of 2009 found Comet Lulin glowing at 7th magnitude in Libra, near Lambda (&lambda) Librae not far from the border of Scorpius. Day by day Lulin is getting higher in the southeast (as seen from mid-northern latitudes) just before start of dawn. It was hidden in the solar glare during November and most of December. Prior to that, observers had followed it from as early as May 2008, when it was 14th magnitude, through late October, when it had risen to 8th.


Moving westward across Libra, the comet passes 0.1° south of 47 Librae, and 0.9° north of Lambda Librae, on the morning of January 8th. The comet is at perihelion (closest approach to the Sun) on January 10th, at a solar distance of 1.2 a.u. (181 million km).


Rather than fading after perihelion, Lulin is expected to brighten further as its diminishing distance from us more than compensates for it moving away from the Sun.


February: Peak Brightness, Peak Speed


As Comet Lulin nears Earth its speed across the sky will increase. The beginning of February sees the 6th- or 7th-magnitude comet rising around midnight, and it passes within 1° of the wide binocular double star Alpha Librae on the night of February 5–6. Initially moving at about 1° per day, Lulin will be creeping westward at 2° per day by February 11th, when it crosses into Virgo and passes within a quarter degree of Lambda Virginis.


Five days later, on the 16th, comet Lulin — now perhaps 5th or 6th magnitude — will pass 3° north of Spica, and the comet's speed will have increased to 3° per day.


On the night of February 23rd, near its peak brightness, Comet Lulin is passing 2° south-southwest of Saturn.


Lulin's closest approach to Earth, 0.41 a.u. (61 million km), occurs on February 24th, when the comet may reach a peak of magnitude 5. By now it's visible in late evening (after rising around the end of astronomical twilight) and remains in view for the rest of the night.


And it's speeding along at just over 5° per day! That's about 1 arcsecond every 5 seconds of time, enough to show obvious motion during a short telescopic observing session. Similarly, that's 1 arcminute per 5 minutes of time if you're using binoculars.


After that Lulin moves away from both Earth and the Sun, so it fades quickly. The evening of February 27 will see it at 5th or 6th magnitude within 1° of Regulus.


Weird Orbital Geometry


Strangely, as you may have noticed on the charts, this comet is traveling almost exactly along the ecliptic — backward! Could this really be just be a coincidence? The comet's nearly parabolic orbit indicates that it has never really interacted with the planets at all. Yet its orbital inclination is 178.4°, meaning that it's orbiting in the opposite direction from the planets just 1.6° from the ecliptic plane. (Manipulable 3-D orbit diagram).


Tails and Antitails


Because the comet stays nearly on the ecliptic, its tail (which points away from the Sun) aligns with the ecliptic and with the comet's own direction of motion across the sky. This is indicated by the direction the tail is pointed on the comet symbols on the finder charts linked to above.


Moreover, because Earth remains in the comet's own orbital plane, we're likely to see the comet with a very thin tail and an antitail, a spike pointing in almost the opposite direction from the main tail, for months on end. Why? In three dimensions a comet's dust tail is often wide but it's always thin, confined to the comet's orbital plane. When we are in or near this plane, we can sometimes see parts of the wide, thin dust tail on opposite sides of the comet's head. We pass through most comets' orbital planes briefly. But this time, the situation will last and last.


And indeed, as of January 7th Lulin did have an antitail, as shown in this image taken by Karzaman Ahmad in Malaysia with a 20-inch scope (image courtesy Spaceweather.com.) Here's another image, from Ernesto Guido, Giovanni Sostero and Paul Camilleri, taken January 8th. Here's a photo gallery of more.


A comet's blue-green gas tail, on the other hand, always points nearly in a straight line away from the Sun in space. Cometary gas is blown directly away from the Sun at high speed by the solar wind.


March: Following Lulin Out


Comet Lulin crosses from Leo into Cancer at the beginning of March. The night of March 5 sees the 6th-magnitude comet within 2° of both Delta (δ) Cancri and the Beehive Cluster (M44). It will make for a fine sight, particularly in high-powered binoculars. Think photo opportunity.


Another nice conjunction occurs on March 16th when the comet, now around 7th or 8th magnitude (and setting in the early hours of the morning), is 1° from Delta Geminorum.


As Comet Lulin recedes, its passage across our sky will slow. Indeed, from the end of March to the end of May (when Lulin may have faded to 11th magnitude) it will stay within a narrow, 3° strip of sky bounded by Epsilon (ε), Mu (μ), and 36 Geminorum.


Comet Lulin won't return again to the inner solar system for more than a thousand years.


Cooperative Discovery


Comet C/2007 N3 (Lulin) was discovered by Quanzhi Ye, a student (age 19) at Sun Yat-sen University in mainland China, as an apparently asteroidal object on images taken by Chi Sheng Lin (National Central University, Taiwan) with a 16-inch telescope at Lulin Observatory in Taiwan on the night of July 11, 2007. A week later, confirming images revealed the telltale presence of a coma. In China and Taiwan, the comet has been hailed as the "Comet of Cooperation."


Lulin was one of 223 comet discoveries on images taken from the ground and in space in 2007, an all-time record.

NASA Mystery of Methane on Mars

Michael J. Mumma: My name is Michael Mumma. I work at Goddard Space
Flight Center for the National Aeronautics and Space Administration in
Greenbelt, MD. Our team has discovered methane on Mars.

The surprising thing about methane on Mars is that--first, that we
detect it meaning it's recently generated. But in addition, we find
that it's being released from several discrete vents--or sites--on the
planet's surface in either mid-summer in the northern hemisphere or
early spring in the southern hemisphere on Mars, and yet at a later
season, we see essentially no methane.

The big question is, "What is the origin of this methane now being
released?" The two principal areas are first, by analogy with the
earth, it could be released and produced initially--primarily--by
biology. This would be microbial activity acting on certain chemicals
below the surface and then producing methane as a byproduct.

But of course, we can't state with certitude that it is biologically
produced, and so we also consider geochemical mechanisms in which
carbon dioxide is actually combining with water and producing methane
under very high temperatures and pressures--and that methane can then
be released into the atmosphere separately.

One of the most important consequences of our discoveries is that
we've identified certain "signposts" on Mars that basically are like
little flags that say, "Come here, here I am." NASA has several
missions along these lines; one is called the Mars Science Laboratory.
One of the key objectives is to understand whether life ever arose on
Mars by sampling the material on the surface and then evaluating that
in terms of its origins. You can then appreciate that if you go to
this right location, you may in fact be able to identify whether
biology was at work, or geochemistry.

The Curious Case of Martian Methane

The Curious Case of Martian Methane
 
Those of you old enough to have lived through the 1960s might remember comedian Bill Dana's routine involving "Jose Jimenez," the first astronaut in space. When asked whether there might be life on Mars, the reluctant space pioneer replied, "Maybe . . . if I land on a Saturday night."
 
Be honest: deep down inside, don't you wish that life of some kind exists (or at least once existed) on Mars? Whether you do or don't, the news today out of NASA's Washington headquarters would really have piqued Jose's interest.
 
Red areas indicate where in 2003 ground-based observers detected concentrations of methane in the Martian atmosphere, measured in parts per billion (ppb). Click on the image to see this view compared with a map of the Martian surface.
 
Mars, it seems, occasionally burps sizable volumes of methane gas. This, in itself, isn't exactly fresh news. Both ground-based telescopes and Europe's Mars Express orbiter detected whiffs of Martian methane several years ago.
 
However, since then Michael Mumma (NASA-Goddard Space Flight Center), Geronimo Villaneuva (Catholic University), and others have reanalyzed their 2003 spectroscopy with a new technique that's more sensitive to the methane signature — and in doing so they've found that broad, relatively concentrated plumes of methane were floating over the planet's northern hemisphere at that time. Details appear in a paper published online today in Science Express.
 
Not only is this the "first definitive detection of methane on Mars," as Mumma notes, but he and his team have a fairly good idea of where it came from. The plumes appeared to the east of Arabia Terra, the Nili Fossae region, and the southeast section of Syrtis Major. All three locales appear to have been saturated with liquid water long ago, and in fact the team found water vapor in the plumes as well.
 
Methane shouldn't exist in the thin Martian atmosphere — it's easily destroyed by exposure to the ultraviolet-rich sunlight that streams onto the planet. So where did these plumes come from? The team offered three possibilities during today's press briefing.
First, it might have come from an impacting comet. Some comets do contain methane, at an abundance of about 1% relative to their water, and a recent impact can't be entirely ruled out. But atmospheric specialist Sushil Atreya (University of Michigan) says that's really unlikely, because it'd take a comet a couple of miles across to generate so much methane. Now, with all due respect to Dr. Atreya, I ran the numbers myself and found that a comet less than 1,000 feet (300 meters) across could deliver the 19,000 tons of methane detected in the plumes. But even the crash landing of such a smallish comet would have left a crater so fresh that it would've been very obvious to Mars-orbiting cameras.
 
Second, Mars might literally have burped up methane stored in its interior. It wasn't from a volcano, Mumma notes, because then the methane would have been joined by gases like sulfur dioxide that weren't seen. Instead, buried deposits of iron oxide might have undergone a geochemical reaction (known as serpentization) that releases methane. Then a recent shifting of the crust provided the trapped methane with an escape route to the surface.
 
Finally, there's the "life card." The methane could represent, as noted by geologist Lisa Pratt (Indiana University), the "exhaled breath" of deep-seated colonies of microorganisms. These putative critters — past or present — would feed on hydrogen gas created by the proximity of water to traces of radioactive isotopes and give off methane as a waste product. Again, since the telltale plumes weren't seen before 2003 or since, the methane would have accumulated in some kind of underground reservoir before being released.
 
Pratt adds that some organisms feed on methane rather than excrete it, so either way the gas's detection ups the prospects for Martian biology. But she notes that there's nothing in the observation to tip the scales toward biology versus geochemistry. An experiment on the forthcoming Mars Surface laboratory has the power to deduce the methane's isotopic mix and thus narrow the choices. But NASA recently postponed MSL's launch until 2011 — so all you Marsophiles will just have to be patient.
 
Mumma agrees that it's still a coin flip, but he and Villanueva plan to resume observations to try to make more sense of it all. "We have a total search strategy beginning in August for other molecules," he explains, along with more work to extract the evidence for water from their existing spectra. "We want to pursue both opportunities — what do we expect to see for serpentization or biology? That's the scientific method, and that's how we'll make progress."
 
Interestingly, most of the methane was gone when the team looked again in 2006 — and that's almost as intriguing as finding it in the first place. Exposure to sunlight couldn't have eradicated it so quickly, so some other process was at work. NASA's Phoenix lander discovered the presence of a mildly reactive compound known as perchlorate, and results from the Viking landing in 1976 suggest hydrogen peroxide in the surface dust. Either of these could do the trick.

Tuesday 13 January 2009

C/2007 N3 (Lulin)

Discovery:
This object was initially described as an asteroidal object, when found by Quanzhi Ye (Sun Yat-sen University, Guangzhou, China) on three images obtained by Chi-Sheng Lin (Institute of Astronomy, National Central University, Jung-Li, Taiwan) on 2007 July 11. Lin had acquired the images using the 41-cm Ritchey-Chretien and a CCD camera at Lulin Observatory (Nantou, Taiwan). The magnitude was given as 18.9. Several confirming observations were obtained; however, on July 17, J. Young (Table Mountain Observatory, California, USA) noted a coma 2-3" across, with a bright central core.
 
Historical Highlights:
Using 76 positions spanning the period of 2007 July 11 to 17, B. G. Marsden calculated a parabolic orbit with a perihelion date of 2009 January 7.35. Even more interesting was the perihelion distance of 1.19 AU. Marsden revised his calculations a couple of days later. Using 89 positions spanning the period of July 11 to 19, he determined the perihelion date as January 14.95 and the perihelion distance as 1.24 AU.
 
The comet will pass 0.41 AU from Earth on 2009 February 24.
The comet steadily brightened during the last months of 2008. It was near magnitude 11.0 at the beginning of July, 10.5 at the beginning of August, 10.0 at the beginning of September, and 9.5 at the beginning of October. As the comet approached evening twilight, it was observed by a few observers at low altitude. Chris Wyatt (Australia) saw the comet with his 25-cm reflector on October 18. He gave the magnitude as 8.1 and said the moderately condensed coma was 12' across. J. J. Gonzalez (Spain) saw the comet on October 18 and 19, using 25x100 binoculars, when its altitude was only 7-8 degrees. He gave the magnitude as 8.3 on the last date, while the moderately condensed coma was 4' across. Con Stoitsis (Australia) saw the comet with his 20-cm Dobsonian on October 20. He gave the magnitude as 9.0 and said the moderately condensed coma was 4.5' across. D. A. J. Seargent (Australia) saw the comet for the final time before solar conjunction on October 27. Using 25x100 binoculars, he gave the magnitude as 8.1 and the coma diameter as 5'.
 
Following solar conjunction, the comet was picked up in the morning sky by Gonzalez on December 21. Astronomical twilight was just beginning, while the comet was 7 degrees above the horizon. His 25x100 binoculars revealed a magnitude of 7.6, while the moderately condensed coma was 2.5' across. Based on this observation, the comet's maximum magnitude in late February might reach magnitude 4.

Monday 12 January 2009

LYRA COMET REPORT FOR THE NEW YEAR AND 2008 A YEAR IN ASTRONOMY...

A note for 2009:
2009 is the International year of Astronomy as well as Moon week which is 20th to 26th July to celebrate 40th anniversary of the Apollo Moon Landings...

Comets:
It has been a quiet 2008 for bright Comets and with Comet Boattini probably the best one to see only reaching Magnitude 7 to 8 in the western evening twilight and was a hard object for me to pick out and see due to the bright Sky around may time, it was quickly consumed by the evening twilight sky to re-appear in the early morning skies of July still around magnitude 6 to 7-this comet was seen either side of the Summer solstice but had faded rapidly into August.
Most of the other Comets for 2008 were beyond Magnitude 10 or more and were much too faint for us amature astronomers to pick out-I will keep you all updated and informed about Comet Lulin which is now visible at this time in the early morning skies and will enter the evening skies in February according to reports it has a tail as well as anti tail and is visible in small back garden telescopes right now for early risers.

Upcoming Astronomical Events for 2009:
5 Space shuttle launches are scheduled for this year and sees the return of several comets and 3 of them that may become Binocular Brightness-I will keep you all updated and informed if they do.
January Phenomena:
14th Venus at its Greatest Elongation of 47 Degrees East
15th Saturn 6 Degrees North of the Moon
21st Antares 0.02 Degrees South of the Moon
24th Jupiter in Conjunction with the Sun
26th Annular Solar Eclipse in the Indian Ocean
30th Venus 3 Degrees and Neptune 5 Degrees South of the Crescent Moon.

Planets for January:
Mercury: has been seen for the past 2 weeks low in the South Western Evening Twilight shining as a small pin prick of light at Magnitude +1 and earlier in the Month was close to small Yellow disc of Jupiter in the cold Evening Skies.
Venus: Is now a brilliant object in the South-South Western Evening Skies after Sunset and is shining at magnitude 4.6
Mars: is now too close to the Sun for any kind of Observation.
Dwarf Planet Ceres: now in the Early morning skies amongst the stars of Leo and worth the effort to look at if clear.
Jupiter: in Conjunction with the Sun on the 24th January and has by now been consumed by the Evening Twilight.
Uranus: Has also been consumed by the Western Evening Twilight.
Neptune: was Visible for The early part of the New Year but this also has now faded to the Western Evening Sky.
Dwarf Planet Pluto: Is too close to the Sun at the moment but will gradually appear in the early morning sky.

The Moon:
Full Moon was on the 11th January
Last Quarter is on 18th January
New Moon is on 26th January
First Quarter is on 2nd February
Full Moon is on 9th February

Lighting up times for January and February:
January 15th 16.51 Hours U.T
January 31st 17.18 Hours U.T
February 15th 17.45 Hours U.T
February 28th 18.09 Hours U.T

Saturday 10 January 2009

A Comet Approaches

Space Weather News for Jan. 9, 2009
http://spaceweather.com

APPROACHING COMET:  Comet Lulin (C/2007 N3), discovered in 2007 by a collaborative team of Taiwanese and Chinese astronomers, is swinging around the sun and approaching Earth. The photogenic comet has a bright tail and an "anti-tail" visible in mid-sized backyard telescopes.  At closest approach in February, Comet Lulin is expected to brighten to naked-eye visibility. Visit http://Spaceweather.com for sky maps, pictures and more information.

NEW SUNSPOTS:  For the second time this week, a sunspot is coalescing on the surface of the sun.  The spot's high latitude and magnetic polarity identify it as a member of new Solar Cycle 24; its appearance continues a recent trend of gradually intensifying new-cycle solar activity.  The spot is growing rapidly and may soon provide a nice target for backyard solar telescopes.

FULL MOON ALERT!  This weekend's full Moon is the biggest and brightest of 2009. It's a "perigee Moon" as much as 50,000 km  closer to Earth than other full Moons we'll see later this year.   Perigee moonlight shining through icy winter air can produce beautiful halos, coronas, moondogs and other atmospheric optics phenomena.  Sample photos are featured on today's edition of Spaceweather.com.

The Dark Days of Winter-Something Cheerful Not...

The period between the first week in December and the first week in January could well be called the "dark days" for the mid-northern latitudes. At latitude 40 degrees north, earliest sunset occurs around 8 December each year, and latest sunrise occurs around 5 January. The day with the least amount of daylight is the winter solstice, the first day of winter, around 21 December. Why are not all these dates the same? The answer is not simple. There are two effects which, together, determine the local time of Sun phenomena, such as sunrise, sunset, and transit. One is the called the Equation of Time, the other is the Sun's declination.
 
The Equation of Time is a way of describing the variation in the time of Sun-related phenomena within our standard 24-hour timekeeping system. In any time zone, the Equation of Time is simply the difference between 12:00 noon on a clock and the actual time of the Sun's transit (sundial noon) across the central meridian of the time zone. The time between successive transits of the Sun - the length of the solar day - varies considerably over the year. It is itself determined by two factors, both dependent on the position of the Earth in its orbit. Suffice it to say that from mid-November to early February these two factors work together to make the solar day longer than 24 hours: in late December, as much as 30 seconds longer than 24 hours. Since we don't adjust our clocks for this effect, the Sun's transit moves later and later each day during this period.
 
All other things being equal, the times of all Sun phenomena are tied directly to the time of transit. But all other things are not equal. The Sun's declination, its angular distance above or below the equator, changes on a yearly cycle, causing our seasons. The Sun's declination determines the maximum height of the Sun in the sky on any given day, hence the azimuth of the sunrise and sunset points, and the length of time the Sun is above the horizon. Most of us know the Sun is at its "lowest point in the sky" on the first day of winter, so we expect the Sun to be above the horizon the least amount of time that day.
 
So two effects determine the times of sunrise and sunset: the Equation of Time and the Sun's declination. But their relative magnitudes vary. In late December, the daily rate of change of the Sun's declination is quite small and is, of course, zero at the December solstice; "solstice" means "Sun stationary". However, the daily rate of change of the Equation of Time reaches a maximum just a few days later. Thus in late December it is the Equation of Time that has the dominant influence over the changes in sunrise and sunset times from one day to the next. In fact, the Equation of Time dominates, at latitude 40 degrees north, from about 8 December to 5 January. Outside of these few weeks, the Sun's declination changes are dominant. These two dates represent the dates on which the magnitudes of the two effects "cross over" at this latitude. (At higher latitudes, the crossover dates are closer to the solstice since the declination effect is greater there.)
 
The 8 December crossover day is the date of earliest sunset. Why? In the weeks before solstice, the two effects act in opposite directions on the time of sunset: the declination effect pulling it earlier and the Equation of Time pushing it later. On 8 December the Equation of Time begins to dominate and sunset begins to move later. Meanwhile both effects are pushing sunrise later and later. After solstice, the situation reverses. Both effects push sunset later. But for sunrise, the declination effect now pulls it earlier while the Equation of Time effect continues to push it later. The Equation of Time prevails until 5 January, when the declination effect takes over and sunrises begin to move earlier. So 5 January is the date of latest sunrise.
 
A similar situation occurs at the summer solstice, although the effect is not as extreme. Solstice occurs around 21 June, but at latitude 40 degrees north the earliest sunrise occurs around 14 June and the latest sunset around 28 June.

Saturday 3 January 2009

New Year Sky Show

Space Weather News for Dec. 29, 2008
http://spaceweather.com

NEW YEAR: What a way to end the old year. On Dec. 31st, Venus and the slender crescent Moon will gather together high in the southwestern sky for a beautiful conjunction visible for hours after sunset.  The two brightest objects in the night sky can be seen through city lights and even fireworks--so everyone can enjoy the show. Meanwhile, closer to the horizon, Mercury and Jupiter are converging for their own Dec.31st conjunction. This one is not so easy to see, but rewarding for those who make the effort to find the two planets shining through the rosy glow of sunset.

Visit http://spaceweather.com for sky maps and photos of the converging planets.

BONUS: Is Venus really bright enough to cast shadows?  The answer is yes, and the proof may be found on today's edition of Spaceweather.com.  A French photographer has captured rare images of Venus casting a shadow and he has even made a movie of the shadow in motion.

First Meteor Shower of 2009

Space Weather News for Jan. 2, 2009
http://spaceweather.com

FIRST METEORS OF 2009:  The annual Quadrantid meteor shower peaks on Jan. 3rd when Earth enters a stream of debris from shattered comet 2003 EH1. The timing of the encounter favors observers in western North America and across the Pacific Ocean who could see dozens to hundreds of meteors during the dark hours before sunrise this Saturday morning. Visit http://spaceweather.com for a sky map and more information.

SOMETHING NEW: For the new year, Spaceweather.com is pleased to announce a new service: Space Weather Radio, broadcasting live "sounds from space" around the clock.  Today you can listen to the Air Force Space Surveillance Radar in Texas.  When a meteor passes over the facility--ping!--there is an audible echo. (Activity should be high during the Quadrantid meteor shower this weekend.)  In the near future we'll be adding broadcasts of solar radio bursts and VLF signals from the ionosphere. The streams are punctuated by Daily Space Weather Updates from Dr. Tony Phillips.  Click here to begin listening:  http://SpaceweatherRadio.com

Jupiter and Mercury in the Evening Twilight

S.P.A Forum...

Astrocomet
Joined: 01 May 2006
Posts: 245
Location: Kessingland, Lowestoft, Suffolk
Posted: 01 Thu Jan, 2009 1:54 pm Post subject:
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Grey cloud these past 2 days from my location here in suffolk-can't even see the Crescent Moon with Venus let alone Jupiter and Mercury-I fear it may be too late if this continues and they will probably be consumed by the evening Twilight before I get to see these 2....

Astrocomet
Joined: 01 May 2006
Posts: 245
Location: Kessingland, Lowestoft, Suffolk
Posted: 02 Fri Jan, 2009 9:23 pm Post subject:
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Luvly and clear this evening looking out to the South West after the Sun had set around 16.03 U.T and lighting up time occurring half and hour later at 16.33 U.T and around that time I could pick out the small bland yellow disc of Jupiter low in the South South West and the small white pin prick of Mercury just along from it and a little higher up low in the yellow orange glow of the cold evening twilight about half an hour before they both disappeared over the Horizon into dark cloud and haze.

Venus and the Crescent Moon higher up in the South was unmissable and unmistakable-looking like a glittering white Diamond against a dark blue sky.

A fantastic view of them and I was very pleased to have seen them after making the effort to get to a clear Southern Horizon at the back of the Village Church where I live and well worth being out in the cold to see them-very pleased...
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Good Clear Skies