Thursday, October 31, 2013

Comet ISON in November

Comet ISON will continue to brighten throughout the month as it nears its late November perihelion (closest point to sun). ISON will pass very close to the bright star Spica and the planet Saturn, both in the constellation Virgo.  Its perihelion on November 28 will be an exciting time. The comet will come within 1.2 million km of our sun’s surface. If all goes well, and the comet doesn’t break up (as comets sometimes do), the terrific heating Comet ISON will undergo when it’s closest to our parent star might turn the comet into a brilliant object. Some are predicting that ISON will become as bright as a full moon! That would make Comet ISON a daylight object, briefly. Remember, though, at perihelion, Comet ISON will appear close to the sun on the sky’s dome (only 4.4° north of the sun on November 28) Impossible and Dangerous for us to try to find ISON.

Date       UT      R.A. (J2000) Decl.   El.    m     Sky Motion
            h m s                                      "/min
2013 10 31 000000 11 07 28.0 +06 59 53   52.3   8.1    3.38
2013 11 01 000000 11 12 24.0 +06 21 40   52.0   7.9    3.53
2013 11 02 000000 11 17 32.9 +05 41 29   51.5   7.8    3.69
2013 11 03 000000 11 22 55.5 +04 59 14   51.0   7.7    3.87
2013 11 04 000000 11 28 33.0 +04 14 47   50.4   7.5    4.06
2013 11 05 000000 11 34 26.3 +03 28 00   49.8   7.4    4.26
2013 11 06 000000 11 40 36.6 +02 38 45   49.0   7.2    4.47
2013 11 07 000000 11 47 05.1 +01 46 55   48.2   7.1    4.70
2013 11 08 000000 11 53 53.1 +00 52 23   47.3   6.9    4.94
2013 11 09 000000 12 01 01.9 -00 04 57   46.3   6.7    5.19
2013 11 10 000000 12 08 32.9 -01 05 12   45.2   6.6    5.46
2013 11 11 000000 12 16 27.7 -02 08 24   43.9   6.4    5.74
2013 11 12 000000 12 24 47.6 -03 14 36   42.6   6.2    6.04
2013 11 13 000000 12 33 34.3 -04 23 46   41.1   6.0    6.34
2013 11 14 000000 12 42 49.2 -05 35 50   39.6   5.8    6.65
2013 11 15 000000 12 52 33.9 -06 50 39   37.9   5.6    6.97
2013 11 16 000000 13 02 49.7 -08 08 00   36.0   5.4    7.29
2013 11 17 000000 13 13 38.0 -09 27 32   34.1   5.2    7.61
2013 11 18 000000 13 24 59.8 -10 48 50   32.0   5.0    7.93
2013 11 19 000000 13 36 56.2 -12 11 21   29.8   4.7    8.23
2013 11 20 000000 13 49 28.0 -13 34 23   27.5   4.4    8.53
2013 11 21 000000 14 02 35.7 -14 57 08   25.0   4.1    8.81
2013 11 22 000000 14 16 20.1 -16 18 43   22.5   3.8    9.07
2013 11 23 000000 14 30 42.1 -17 38 03   19.9   3.5    9.33
2013 11 24 000000 14 45 43.4 -18 54 00   17.1   3.0    9.59
2013 11 25 000000 15 01 28.0 -20 05 13   14.3   2.5    9.90
2013 11 26 000000 15 18 05.4 -21 10 01   11.4   1.8   10.32
2013 11 27 000000 15 35 59.2 -22 05 33    8.2   0.7   11.09
2013 11 28 000000 15 56 29.3 -22 43 30    4.6  -1.3   13.34
2013 11 29 000000 16 23 17.6 -19 52 41    1.8  -4.5   14.51
2013 11 30 000000 16 21 22.3 -16 20 25    5.3  -0.2    6.75

Wednesday, October 23, 2013

Meanwhile another Comet explodes!!!

Almost 450 million km from Earth, Comet C/2012 X1 (LINEAR) has
exploded. Amateur astronomers are reporting a 200-fold increase in the
comet's brightness on Oct. 20th, and the comet's atmosphere or "coma"
now resembles that of exploding Comet 17P/Holmes in 2007. Using a
remotely-controlled 0.5 meter telescope in New Mexico, European
observers Ernesto Guido, Martino Nicolini and Nick Howes took this
picture of the spherical explosion on Oct 21st:



"The predicted magnitude of the comet, pre-outburst, was about +14,"
says Guido. "Now it is close to +8.5." This is below the threshold for
naked-eye visibility, but bright enough for backyard telescopes
equipped with digital cameras.

Prompted by the reports of Guido et al, Romanian amateur astronomer
Maximilian Teodorescu observed the comet on Oct. 22nd, confirming its
brightness and spherical structure: image. "It looked exactly like
Comet Holmes back in 2007," says Teodorescu.

Located in the constellation Coma Berenices, Comet LINEAR X1 rises in
the east about an hour before the sun. The low altitude of the comet
in morning twilight is a challenge. "I could not see the comet through
the eyepiece of my 4.5 inch refracting telescope," adds Teodorescu,
"but the camera detected it easily enough." The comet could become
brighter in the days ahead as its coma expands. Monitoring is
encouraged.

Monday, October 14, 2013

Comet ISON as seen from the surface of Mars on October 1


If you were standing on the surface of Mars, at the North Pole, how would Comet ISON appear to you, as it crosses the Martian sky?

Courtesy: http://shadowandsubstance.com

Mars Regulus ISON conjunction

Mars, the 1st-magnitude star Regulus, and Comet ISON have gathered together in the pre-dawn sky only a few degrees apart. Comet ISON is invisible to the naked eye, but Mars and Regulus are bright enough to see without optics. They form a pretty red-blue "double star" that can lead telescopic observers to the comet.







Friday, October 4, 2013


 The Path of Comet ISON


Comet McNaught as seen from a Dark site with huge tail and Moon shining bright above horizon
Comet ISON is expected to be visible just like this comet.


Comet ISON was discovered on Sept 21, 2012, by Russian astronomers Vitali Nevski and Artyom Novichonok using a telescope of the International Scientific Optical Network (ISON) located near Kislovodsk.
Shortly after discovery, it was noted that some of the orbital elements of C/2012 S1 were similar to that of the Great Comet of 1680, which suggested the two comets may have fragmented from the same parent body. However, further observations of ISON have shown that the two comets are not related.
Like all comets, ISON is a clump of frozen gases mixed with dust. Often described as "dirty snowballs," comets emit gas and dust whenever they venture near enough to the sun that the icy material transforms from a solid to gas, a process called sublimation. Jets powered by sublimating ice also release dust, which reflects sunlight and brightens the comet.
On Nov. 28, ISON will make a sweltering passage around the sun. The comet will approach within about 1.2 million km of its visible surface, which classifies ISON as a sungrazing comet. In late November, its icy material will furiously sublimate and release torrents of dust as the surface erodes under the sun's fierce heat, all as sun-monitoring satellites look on. Around this time, the comet may become bright enough to glimpse just by holding up a hand to block the sun's glare.
Sungrazing comets often shed large fragments or even completely disrupt following close encounters with the sun, but for ISON neither fate is a foregone conclusion.
C/2012 S1 will come to perihelion (closest approach to the Sun) on 28 November 2013 at a distance of 0.012 AU (1,800,000 km) from the centre point of the Sun. Accounting for the solar radius of 695,500 km, C/2012 S1 will pass approximately 1,100,000 km above the Sun's surface. Its trajectory is nearly parabolic, which suggests that it may be a dynamically new comet coming freshly from the Oort cloud. On its closest approach, C/2012 S1 will pass about 0.0724 AU (10,830,000 km) from Mars on 1 October 2013, and it will pass about 0.429 AU (64,200,000 km) from Earth on 26 December 2013.
Following ISON's solar swing by, the comet will depart the sun and move toward Earth, appearing in morning twilight through December. The comet will swing past Earth on Dec. 26, approaching within 64.2 million km or about 167 times farther than the moon.
Comet C/2012 S1, better known as comet ISON, may become a dazzling sight as it traverses the inner solar system in late 2013. During the weeks before its Nov. 28 close approach to the sun, the comet will be observable with small telescopes, and binoculars. Observatories around the world and in space will track the comet during its fiery trek around the sun. If ISON survives its searing solar passage, which seems likely but is not certain, the comet may be visible to the unaided eye in the pre-dawn sky during December.
Earth will pass near the orbit of C/2012 S1 on 14–15 January 2014, well after the comet has passed, when micron-sized dust particles blown by the Sun's radiation may cause a meteor shower, or noctilucent clouds. However, both events are highly improbable. Because Earth just passes near C/2012 S1's orbit, not actually through the tail, the chances that a meteor shower will occur are very slim. In addition, meteor showers from long period comets that make just one pass into the inner solar system are very rare, if ever recorded.
The possibility that small particles left behind on the orbital path—almost one hundred days after the nucleus has passed—could form noctilucent clouds is also slim. A significant amount of dust should enter Earth's atmosphere, and besides that, no such events are known to have taken place in the past, under similar circumstances.

5 Things to know about ISON
Comet ISON may put on a show when it skims through the sun's atmosphere later this year. Right now, it's still far away, but we're keeping track and will give you regular updates. Here are five key facts about ISON as we await its arrival:

1.      What's with the funky name?
Comet ISON was named after their night-sky survey program, the International Scientific Optical Network, a group of observatories in 10 countries organized to track objects in space.
2.     How big is it?
Measurements taken by the Hubble Space Telescope in April indicate ISON has a nucleus that is 5 to 6.5 kms across. The comet's head, or coma, is estimated to be 5000 kms across, or 1.2 times the width of Australia. The Hubble team says its dust tail extends more than 93,000 kms -- more than twice the circumference of Earth, and far beyond the telescope's field of view.
3.     OK, it's a comet. Aren't there lots of comets? Why is this one special?
Some early comet prognosticators have tagged ISON "the comet of the century."
"Comet ISON has the potential to be among the brightest comets of the last 50 years," Dennis Bodewits, an astronomer at University of Maryland at College Park, told NASA.
Bodewits and other astronomers used NASA's Swift satellite to estimate ISON's water and dust production.
4.     How to tell space rocks apart
"Comet ISON belongs to a class of comets called Sungrazing comets," Karl Battams of the Naval Research Lab told CNN. This means it will fly relatively close to our sun. These comets "teach us not only about comets, but also yield valuable and unique results about the sun," he said.
“But before you get too excited, other experts caution it's too early to know what ISON will do”
"Predicting the behavior of comets is like predicting the behavior of cats -- can't really be done," Don Yeomans of NASA's Near-Earth Object Program told CNN.com in March.

5.     When can I see it?
In November, ISON is expected to fly through the sun's atmosphere at about 700,000 miles above the surface. If it survives the sun's heat, experts say it might glow as brightly as the moon and be briefly visible in daylight. Its tail might stretch far across the night sky. Or the sun could cause it to break apart.
6.     What if ISON breaks apart? Is Earth in danger?
No. Experts say the comet won't threaten Earth. In fact, even if it breaks up, Battams says it could put on a big show.
"If Comet ISON splits, it might appear as a 'string of pearls' when viewed through a telescope," Battams told NASA. "It might even resemble the famous Comet Shoemaker-Levy 9 that hit Jupiter in 1994."
Whatever happens to ISON, sky watchers in the Northern Hemisphere should have a good view for several months. NASA says it will pass almost directly over the North Pole and will be visible all night long.



Track comet ISON all October using the following illustrations:


Comet ISON as seen on October 1, 2013 in due East just before Sunrise



Comet ISON close to Mars and Moon as seen on Oct. 11, 2013 in due East just before sunrise



Comet ISON on October 21, 2013 near to Mars as seen in the East just before sunrise



Orbital Parameters for Comet ISON as seen from various points in Space

Orbital parameters for Comet ISON*

Position

Right ascension                                                 9h 42.6m
Declination                                                        16° 50'
Constellation                                                    Leo
Distance from Earth                                        2.043 AU
Last observed magnitude                              15.0
Date of last reported observation                03/10/2013
Angular separation from Sun                      49.1°
Ecliptic latitude                                              3.8°

Orbit

Distance from Sun                                          1.581 AU
Perihelion                                                         0.012 AU   (28/11/2013)
Eccentricity                                                       1.000002
Inclination to ecliptic                                   62.4°
Speed relative to Sun                                     33.500 km/s


* Source: www.heavens-above.com