Saturday, November 30, 2013

COMET ISON LIVES

Cancel the funeral. Comet ISON is back from the dead. On Nov. 28th, Comet ISON flew through the sun's atmosphere and appeared to disintegrate before the cameras of several NASA and ESA spacecraft. This prompted reports of the comet's demise. Hours later the comet revived, sprouted two tails and rapidly brightened. It is now receding from the sun with a fair chance of becoming a photographic object in the morning sky as early as Dec. 2nd or 3rd. A new coronagraph movie from SOHO documents the flyby (updated Nov. 30 @ 00:09 UT):



Before the flyby, experts had made many predictions about what might happen to the comet, ranging from utter disintegration to glorious survival. No one predicted both.

Karl Battams of NASA's Comet ISON Observing Campaign says, "[colleague] Matthew Knight and I are ripping our hair out right now as we know that so many people in the public, the media and in science teams want to know what's happened. We'd love to know that too! Right now, here's our working hypothesis:

"As comet ISON plunged towards to the Sun, it began to fall apart, losing not giant fragments but at least a lot of reasonably sized chunks. There's evidence of very large dust in the long thin tail we saw in the [SOHO coronagraph] images. Then, as ISON plunged through the corona, it continued to fall apart and vaporize, losing its coma and tail completely just like sungrazing Comet Lovejoy did in 2011. What emerged from the Sun was a small but perhaps somewhat coherent nucleus that has resumed emitting dust and gas for at least the time being."

Battams emphasizes that it is too soon to tell how big the remnant nucleus is or how bright the resurgent comet will ultimately become. "We have a whole new set of unknowns, and this ridiculous, crazy, dynamic and unpredictable object continues to amaze, astound and confuse us to no end. We ask that you please be patient with us for a couple of days as we analyze the data and try to work out what is happening."

Courtesy - spaceweather.com

Friday, November 29, 2013

Few updates on universetoday.com showing fate of ISON

Update, 8:35 p.m. EST: Uncertainty about Comet ISON’s fate likely will persist for some time. Karl Battams just tweeted that after 2,000 sungrazing comet observations, he has never seen brightening in the same way that ISON (or its remains) appear to be doing right now. We’ll keep watching. Real-time images are available on this website.

Update, 6:30 p.m. EST: An excellent blog post from Phil Plait (who writes the Bad Astronomy blog on Slate) summarizes his take of the comet’s fate; debris (most likely, he says) continues to show up in images. An except: “It held together a long time, got very bright last night, faded this morning, then apparently fell apart. This isn’t surprising; we see comets disintegrate often enough as they round the Sun. ISON’s nucleus was only a couple of kilometers across at best, so it would have suffered under the Sun’s heat more than a bigger comet would have. Still, there’s more observing to do, and of course much data over which to pore.”

Update, 4:40 p.m. EST: On Twitter, the European Space Agency (quoting SOHO scientist Bernhard Fleck) said the comet is gone. Separately, the Naval Research Laboratory’s Karl Battams posted that he thinks recent observations show debris from ISON, but not a nucleus. Astronomers are still monitoring, however.

Update, 3:56 p.m. EST: Something has emerged from perihelion, but the experts are divided as to whether it’s leftovers of ISON’s tail, or the comet itself. 

Comet ISON Fizzles as it Rounds the Sun

Comet ISON went around the sun on Nov. 28, 2013. Several solar observatories watched the comet throughout this closest approach to the sun, known as perihelion. While the fate of the comet is not yet established, it is likely that it did not survive the trip. The comet grew faint while within both the view of NASA's Solar Terrestrial Relations Observatory, and the joint European Space Agency and NASA's Solar and Heliospheric Observatory. The comet was not visible at all in NASA's Solar Dynamics Observatory.



"We didn't see Comet ISON in SDO," said Dean Pesnell, project scientist for SDO.


This image from NASA's Solar Dynamics Observatory shows the sun, but no Comet ISON was seen. A white plus sign shows where the Comet should have appeared. It is likely that the comet did not survive the trip.
Image Credit: NASA/SDO

"So we think it must have broken up and evaporated before it reached perihelion."

While this means that Comet ISON will not be visible in the night sky in December, the wealth of observations gathered of the comet over the last year will provide great research opportunities for some time. One important question will simply be to figure out why it is no longer visible.

Courtesy - Karen C. Fox
NASA's Goddard Space Flight Center, Greenbelt, Md. NASA/SDO/ESA/SOHO/GSFC

Thursday, November 28, 2013

ISON animation of images till few hours back




ISON updates

Comet ISON is brightening rapidly as it plunges into the sun's atmosphere. At closest approach around 1:45 p.m. EST (18:45 UT) on Nov. 28th, the comet will be little more than a million kilometers above the sun's fiery surface. Temperatures around ISON's icy nucleus could rise as high as 5000 deg C.  No one knows if it can survive that kind of baking.

Researchers have been wondering what might happen if a CME strikes Comet ISON. They might find out before the day is over. As the movie shows, CMEs are billowing away from the sun in all directions. Avoiding a collision will become increasingly difficult as the comet moves closer to active regions on the sun's surface.

During the hours around closest approach, NASA's Solar Dynamics Observatory (SDO) will take high-resolution pictures of the comet flying through the sun's atmosphere. This diagram illustrates the sequence of events:



Usually, SDO points straight at the sun. In this case, however, the observatory is being offset and moved three times to track the speeding comet. SDO images of sungrazing Comet Lovejoy in Dec. 2011 were dramatic. Comet ISON could be even better.

Wednesday, November 27, 2013

Comet Ison enters SOHO's LASCO C3 field of view

Created from first 8 images 

IS COMET ISON IN TROUBLE?


Astronomers using the IRAM millimeter telescope in Spain are reporting a sharp change in Comet ISON. "We observe consistent, rapid fading of the molecular emission lines between Nov. 21 and Nov. 25 by at least a factor of 20. This may indicate that the nucleus is now at best marginally active or that... it no longer exists," says Michal Drahus of Caltech.

Astronomer Karl Battams of NASA's Comet ISON Observing Campaign comments: "[The fading emission lines] could indicate that the nucleus has completely disrupted, releasing an enormous volume of dust while significantly reducing emission rates. Fragmentation or disruption of the nucleus has always been the highest risk factor for this comet so if this has indeed happened then while unfortunate, it would not be a surprise."

"However," he continues, "these reports are new, and while they are undoubtedly valid, we do still need to keep observing the comet to be sure what it happening. Remember: Comet ISON is a dynamically new sungrazing comet, fresh in from the Oort Cloud, and the last time we saw an object like this was never! Furthermore, a sungrazing comet just three days from perihelion has never been studied in this kind of detail - we're breaking new ground! When we factor in your standard 'comets are unpredictable' disclaimer, what we have is a huge recipe for the unknown.

Courtesy - Spaceweather.com

Tuesday, November 26, 2013

ISON few hours from entering into SOHO's C3 field of view

In another 10 hours  enters in SOHO's LASCO C3 field of view at 2:00 UT (7:30 IST) Nov 27th

Is Comet ISON disintegrating?

There has talk for some days about whether Comet ISON has fragmented. The sungrazing comet experts were saying no, but Monday morning Karl Battams – one of the great communicators at NASA’s Comet ISON Observing Campaign website – said that something is happening to the comet. There are signs it may be fragmenting. He wrote:

    There’s evidence that ISON’s nucleus might not be holding up well (by which I mean falling apart!) It was always a possibility…we’ll see!

Later, he added:

    It is absolutely conceivable that ISON remains in one piece, and is just being a sungrazer.

In other words, the word isn’t in yet on whether ISON is still intact.

The evidence for ISON’s possible disintegration comes in the form of a rapid drop in emissions, in recent days, from a certain kind of molecule (hydrogen cyanide molecule) known to be embedded in cometary ice. At his Bad Astronomy blog on Slate, Phil Plait explained that it’s the ice of a comet like ISON that holds the comet together. ISON is full of fresh ice. It’s a first-time visitor from the Oort comet cloud surrounding our solar system. If enough ice boils off the comet as it gets closer to the sun, the comet will literally fall apart.

But how much ice has ISON lost? Enough so that the comet will fall apart? Meanwhile, dust has also been observed to be pouring from the comet. These signs could mean that ISON’s nucleus has completely disrupted. Or not.

Why don’t astronomers know what will happen? Karl Battams explained:

    … these reports are new, and while they are undoubtedly valid, we do still need to keep observing the comet to be sure what it happening. Remember: Comet ISON is a dynamically new sungrazing comet, fresh in from the Oort Cloud, and the last time we saw an object like this was never! Furthermore, a sungrazing comet just three days from perihelion has never been studied in this kind of detail – we’re breaking new ground here! When we factor in your standard ‘comets are unpredictable’ disclaimer, what we have is a huge recipe for the unknown.

We do know that, after traveling at least a million years from the Oort Cloud, Comet ISON is now plummeting fast toward the sun. Its perihelion or closest point to the sun will be on November 28 – Thanksgiving Day in the U.S. At perihelion, the comet will be traveling at 248 miles per second, encountering solar temperatures of up to 5,000 degrees Fahrenheit.

Thus this week will bring Comet ISON’s moment of truth, its day of reckoning. The comet is close to the sun on our sky’s dome now and won’t be seen from Earth this week except, perhaps, by a few experienced observers. However, NASA and ESA’s fleet of sun-observing spacecraft will be watching it.

If it survives its passage near the sun, Comet ISON will return to our skies in early December, and, indeed, early December may be the best time to try to see the comet … if there is a comet left to see.

Courtesy - earthsky.org

COMET MOVIE--UPDATED

In the movie, which spans a three+ day period from Nov. 20 to Nov. 23, the sun is to the right, off-screen. At first glance, Earth and Mercury appear to be labeled backwards. The strange arrangement is actually correct. This is how the two planets appear from STEREO-A's vantage point over the farside of the sun.



"The dark 'clouds' moving from left to right are density enhancements in the solar wind, and these are what are causing the ripples you see in the comet tails," explains Karl Battams of NASA's Comet ISON Observing Campaign.

The ripples could become even more dramatic if a CME hits the comets. This is Comet ISON's first visit to the sun, but Comet Encke has been here before. In 2007 a CME hit Encke and ripped off its tail. Battams and other researchers hope something similar is about to happen now.
Coutsey - Spaceweather.com

Monday, November 25, 2013

Comet ISON vs. the Solar Storm

In 2007, astronomers were amazed when a solar storm hit Comet Encke.  NASA STEREO spacecraft watched as a CME (coronal mass ejection) struck the comet head on and ripped off its tail.
image
A CME strikes Comet Encke in April 2007.
The same thing could be in store for Comet ISON--only worse.
On Nov. 28th, Comet ISON will pass through the sun's atmosphere, flying little more than a million kilometers above the sun's surface. It will be ~30 times closer to the sun than Encke was in 2007 and more likely to encounter a ferocious solar storm.
"For one thing," says Angelos Vourlidas of the Naval Research Lab and a participant in NASA's Comet ISON Observing Campaign (CIOC), "the year 2007 was near solar minimum. Solar activity was low. Now, however, we are near the peak of the solar cycle and eruptions are more frequent."
"I would absolutely love to see Comet ISON get hit by a big CME," says Karl Battams, an astronomer at the Naval Research Lab who also works with the CIOC. "It won't hurt the comet, but it would give us a chance to study extreme interactions with the comet's tail."
CMEs are magnetized clouds of plasma hurled into space by the explosions of sunspots.  The gas inside a CME is not very dense, so its impact would not shatter a comet's core. The fragile tail is another matter. Comet tails are as gossamer as the CMEs themselves, so the interactions can be intense and unpredictable.

"The CME that ran over Comet Encke back in 2007 was slow, barely creating a pressure pulse by compressing the solar wind ahead of it," notes Vourlidas. "It was this compression which caused the Encke's tail to fly off."
He believes that Comet ISON would experience something more dramatic. "Any CME that hits Comet ISON close to the sun would very likely be faster, driving a shock wave with a much stronger magnetic field.  Frankly, we can't predict what would happen."
Comet ISON entered the field of view of STEREO-A's Heliospheric Imager on Nov. 21st.  Coincidentally, Comet Encke is there, too. Presently, the two comets are being gently buffeted by solar wind and their tails are wagging back and forth accordingly.
splash
The Heliospheric Imager on NASA's STEREO-A spacecraft is tracking Comet ISON as it plunges toward the sun. In this movie, which spans a two day period from Nov. 20 to Nov. 22, 2013, the sun is off-screen to the right. Coincidentally, Comet Encke is present too.
If the sun erupts, both comets could be engulfed by the same CME.  This would turn the two comets into solar probes.  Like wind socks, they would sample the storm from two widely separated locations, giving researchers a rare 3D view of a CME's inner structure.
Comet ISON will be passing over the sun's equator on Nov. 28th on the same side of the sun where a group of active sunspots was recently clustered.  In other words, says Battams, "we're going to be in the 'hot zone' for CMEs."
NASA's entire fleet of solar observatories will be watching when ISON takes the plunge.  This includes STEREO-A and STEREO-B, the Solar Dynamics Observatory, and the Solar and Heliophysics Observatory (SOHO), which NASA operates along with the European Space Agency. If a CME strikes the comet, all of the spacecraft are likely to see what happens.
"It would be pretty new territory for us," says Battams.
"...and a nice preview of what NASA's Solar Probe+ spacecraft might experience when it plunges into the sun in the 2020s," adds Vourlidas.
Stay tuned!
Courtsey - Dr. Tony Phillips Science@NASA

Sunday, November 24, 2013

COMETS IN THE SOLAR WIND

NASA's STEREO-A spacecraft is monitoring Comet ISON as it approaches the sun for a close encounter on Nov. 28th. The latest movie from the spacecraft's Heliospheric Imager captures not only Comet ISON but also Earth, Mercury, and Comet Encke.



In the movie, which spans a two day period from Nov. 19 to Nov. 22, the sun is to the right, off-screen. "The dark 'clouds' coming from that direction are density enhancements in the solar wind, and these are what are causing the ripples you see in the comet tails," explains Karl Battams of NASA's Comet ISON Observing Campaign.

Although the two comets seem to be experiencing the same solar wind, their tails ripple differently. "Encke has kind of long waves in the tail, whereas ISON's seems almost like high-frequency puffs," points out Battams.

Appearances notwithstanding, the two comets might be in two different streams of solar wind. "The most likely explanation is that ISON is in a faster stream," he comntinues. "Imagine holding a flag on a slightly breezy day. The flag will waft gently in the breeze. Now imagine holding it in really strong winds. The flag will be rippling violently, but those ripples will be smaller in amplitude."

Courtsey - spaceweather.com

Saturday, November 23, 2013

SOLAR FLEET PICKS UP COMET ISON

SOLAR FLEET PICKS UP COMET ISON: Because NASA's twin STEREO probes are designed to observe the sun, they can see sundiving comets even when the glare becomes intense. Yesterday, Comet ISON joined Earth, Mercury, and Comet Encke in the field of view of STEREO-A's Heliospheric Imager. Click on the image to view ISON's grand entrance:



"The dark 'clouds' of stuff you see coming from the right are density enhancements in the solar wind, and these are what are causing all the ripples you see in comet Encke's tail," explains Karl Battams of NASA's Comet ISON Observing Campaign. "I can pretty much promise you that we're going to see ISON's tail doing that in a couple of day's time, but on a much larger scale!"

Battams points out another exciting development: Comet Encke and Comet ISON are converging for a photogenic close encounter. "No they're not going to hit each other - in reality they are millions of miles apart - but as seen from the STEREO-A spacecraft, they are going to get very close!" he says. "We are probably a couple of days away from seeing two comets almost side-by-side in that camera, with long tails flowing behind them in the solar wind. To say that such an image will be unprecedented is rather an understatement." Courtesy - Spaceweather.com

Friday, November 22, 2013

WHY IS COMET ISON GREEN?

WHY IS COMET ISON GREEN? Taken by hundreds of people around the world, the pictures of Comet ISON we receive every day vary widely in quality, context and camera settings. However, they all seem to have one thing in common: the comet looks green. Why? To answer this question, Italian amateur atronomers Paolo Corelli and Dario Comino used a high-dispersion spectrometer to analyze light from the comet's atmosphere. Here are there results:



The spectrum of Comet ISON is dominated by a green spectral line from diatomic carbon (C2). This substance is common in the atmospheres of comets, and it glows green when illuminated by sunlight in the near-vacuum of space. The spectrum also shows a weaker but still significant blue emission line from C2. Comet ISON's mixture of green and blue light gives it the aqua hue seen in many long-exposure photographs. Finally, the spectrum reveals a contribution from atomic oxygen.
Courtsey - Spaceweather.com

Thursday, November 21, 2013

COMET ISON PLUNGES TOWARD THE SUN

Comet ISON is plunging toward the sun at 140,000 mph (62 km/s). You can almost feel the velocity in this image taken on the morning of Nov. 20th by astronomers using the 0.4 meter telescope at the Observatorio de la Hita in La Puebla de Almoradiel, Toledo, Spain:



"The comet looked very bright," report the observing team. "The tail was not as well defined today because of the proximity of morning twilight...but still splendid!!"

The comet is brightening rapidly as it approaches the sun. Experienced observers put ISON's rising magnitude near +4.0, well above the threshold of naked-eye visibility. The problem is, the glare of the sun is brightening even faster. Amateur photography of the comet will be possible for a few more days and, soon, only NASA's fleet of solar observatories will be able to track the sundiver.

Observationally speaking, the next big event in the timeline of Comet ISON's journey comes on Nov. 21st when the comet enters the field of view of NASA's STEREO-A spacecraft. The Heliospheric Imager on STEREO-A will pick up the comet just as Earth-bound telescopes begin to lose it. In the days that follow, STEREO-B, SOHO and the Solar Dynamics Observatory will join the hunt, providing continuous views of Comet ISON all the way to perihelion (closest approach to the sun) on Nov. 28th. Stay tuned!
Courtesy - spaceweather.com

Wednesday, November 20, 2013

COMET ISON--ANOTHER OUTBURST?

Astronomers working with the TRAPPIST telescope at ESO's La Silla Observatory report that Comet ISON's production of gas and dust surged another six-fold during the early hours of Nov. 19th. This marks the second outburst since Nov. 13th. Experienced observers put the comet's rising magnitude near +4.0, well above the threshold of naked-eye visibility. The problem is, ISON is approaching the sun and becoming increasingly difficult to observe.



Shahrin Ahmad of Kuala Lumpur, Malaysia, photographed the comet's green core framed by twilight blue on the morning of Nov. 19th:

The situation is only going to worsen as the comet plunges toward its Nov. 28th close encounter with the sun. Amateur photography of the comet will be possible for a few more days and, soon, only NASA's fleet of solar observatories will be able to track the sundiver.

Despite the recent outbursts, which could have been caused by a break up of ISON's nucleus, astronomers with NASA's Comet ISON Observing Campaign believe that the comet is still intact. It will need to be to survive next week's hellish plunge through the sun's atmosphere. If it does survive--a big IF--it could emerge as a splendid naked-eye object for sky watchers in the northern hemisphere.

Observationally speaking, the next big event in the timeline of Comet ISON's journey comes on Nov. 21st when the comet enters the field of view of NASA's STEREO-A spacecraft. The Heliospheric Imager on STEREO-A will pick up the comet just as Earth-bound telescopes begin to lose it. In the days that follow, STEREO-B, SOHO and the Solar Dynamics Observatory will join the hunt, providing continuous views of Comet ISON all the way to perihelion. Stay tuned!

Courtesy - spaceweather.com

Tuesday, November 19, 2013

How to Photograph Comet ISON?

In the previous post we read about the equipment needed to photograph comet ISON. Now we will talk about the methods or settings we can use to picture the comet in particular. Let us have a checklist of objects.

·         A Digital Camera
·         Memory Card
·         Battery/AC adapter
·         Lens of your choice (in case of DSLR)
·         Tripod
·         Camera release cable

Digital Camera
Digital Camera will capture the images digitally so we need to have several settings tested before we can actually go out and capture.

Exposure: it is the duration for which the camera collects the light and makes the image look bright. Every camera may be digital or film, has a shutter which blocks the light. Once the shutter is removed from the front (electronically or manually using the shutter button) the light reaches the sensor of unexposed film roll where the image is formed. A correct exposure will give the much needed details of the coma of the comet and the tails as well. A higher than required exposure will give details of the faint tail but the coma will be very bright and hence very little information can be taken out. Less than desired exposure will mean less information and hence the image will not have enough details on this.

ISO: The sensitivity measure of the sensor of the camera is called as ISO. It is increased logarithmically and is double the previous value of it. The sensitivity of the sensor means that every pixel on the sensor has some electronically controlled value of sensation which reacts once a photon (light particle) comes and falls on it. The energy of the photon striking a pixel is responsible for formation of image. ISO decides how sensitive is your sensor? Lower the ISO value higher will be the threshold value for each pixel and hence more photons or more light will be required to form the image. Higher the ISO value, lesser will be threshold value and hence less photons will be required to form the image. But due to the electronic circuit which have a lot of electronic components, prolong used generate artifacts due to internal heating of the sensor and hence grains in the image are visible. This is called NOISE and is different in different camera at different ISOs. So now you need to find that at what value of ISO your camera is generating how much noise. A little noise is welcome and accepted whereas higher amount of noise is not acceptable and it ruins the image.

Aperture: The amount of light entering through the lens can also be controlled through controlling the opening of the lens. This is called as aperture and usually is measured as ratio between total available and actual opening. Lesser the opening less light will enter through lens and hence the image will be dark. If the aperture is open maximum, then more light will enter and hence the image will be brighter.

Now since you have understood the three main parameters of camera handling, you need to identify what setting will be best for you to shoot this comet. The comet will be barely visible to you from a light polluted city so finding it in camera will be tough. You need a camera which can take long exposures. Now if you are not tracking the comet or compensating the rotation of earth then there will be a trail of stars or comet in the image. At 50mm focal length you cannot give exposure of more than 15 seconds which means you need to collect as much as 200 images for the same. The number of total images can be brought down to 50 images only in case you are at a dark location away from the light pollution of cities. So the rule of thumb says that you cannot exceed your exposure beyond 15 seconds so what else can you do to capture this comet? Remember, higher the focal length, less of exposure time will be possible without trailing the comet in the image.

One option is to increase the ISO. Since it would be winter season for northern hemisphere and early morning will have cold weather, you can increase the ISO to 1600. In normal course it will attract huge amount of noise, but due to cold weather, the noise will be low and you can get a brighter than normal image of ISON. Also you can take DARK FRAMES as much as 20% of the total images and then use it in processing to reduce the noise. The idea is to make the image as much noise free as possible so as to make the image look better and not ‘grainy’,

Aperture shall be open to maximum but one step down. So if you are using a camera lens say 50mm and maximum aperture is f1.8, you shall consider f2 or f2.2 as the right choice. This will improve the sharpness of the object without cutting down the quantity of the cutting light.

Focusing is very important in this case. As the comet will appear as hazy object in the sky, I would suggest that use any bright star and focus your camera. In manual cameras, use the focus to infinity as a nice and easy option. In digital cameras auto focus is provided but it is not a good idea to try auto focus. Point your camera towards the bright star say Sirius (visible around 2 am at good height) and focus it. Once you focus the camera, make sure you don’t change the focus for rest of the night. Now point your camera in east direction towards comet ISON (see older posts for the sky map to find exact position of comet ISON).

Make sure the memory card is empty and can hold at least 300 images in the night. Make sure the battery is charged completely. If the battery was charged few days back and haven’t used it since then still it will be a good idea to charge it again. A spare battery may come handy. Attach the remote timer or if using a laptop then please attach the cord. These days the smart phones are very smart and may allow you to control the camera using your android based smart phones. The apps are free to download and use. All you need is a connecting cable of your camera (mini USB mount) to the mount of your smart phones. These connectors are very easily available in the hardware market or on internet forums. This software also allows you to review the clicked image for better sharpness and focus reviewing. You can do remote shooting from your smart phones as well.

Now since you know all the basics, the challenge is to get everything together and start practicing and shooting. Luckily the comet has breached the 7th magnitude mark and is now within range of small telescopes and binoculars from a dark location. Photographing this comet has now become more easy and hence we shall try our hands on this comet.

Infographic on ISON's path

Infographic on ISON's path

Courtesy - Huffington post 

Monday, November 18, 2013

Comet ISON's tail stretches more than 16 million kilometers

just wow. Comet ISON's tail stretches more than 16 million kilometers from end to end


Courtesy spaceweather.com

workshop on Comet ISON by SPACE in collaboration with Nehru Planetarium

Today is the workshop on Comet ISON by SPACE in collaboration with Nehru Planetarium & NMML (Nehru Memorial Museum and Library). followed by an evening observation conducted by SPACE. Timings are: 02:00 pm - 05:00 pm Comet ISON Workshop and 05:00 pm to 08:00 pm Evening observation.

Sunday, November 17, 2013

Comet ISON battles moonlight, twilight

Spica and Mercury to the rescue as Comet ISON battles moonlight, twilight


Just when Comet ISON came to life, the moon crept back into the morning sky to rob the comet, at least temporarily, of its splendor. With a full moon on tap for tomorrow, expect the comet to get harder to see.


Pity. Moonlight, while among the most lovely of lights we know, reduces contrast and makes it impossible to see faint stars and wispy things like comet tails. Twilight’s no friend of comets either. Tomorrow morning, Comet ISON stands only about 11 degrees (one fist held at arm’s length) above the southeastern horizon at the start of dawn. In three days that shrinks to just 6 degrees as the comet rapidly approaches perihelion on Nov. 28.

We peer through much more air and haze near the horizon than higher up. Notice the moon’s lower edge is dimmed more than the top for this reason. Credit: Bob King

When you tilt your head to look straight up you’re looking through what’s defined as “one airmass”. An airmass includes the air we breathe plus additional haze and suspended particles called aerosols. Now tilt your head down to look 30 degrees or three fists above the horizon and you’re peering through 2 airmasses.  At 10 degrees, that increases to 5.6 airmasses.  Every additional airmass dims the comet by 0.4 magnitudes. That means Comet ISON appears two magnitudes or about 6 times fainter now than if it were high in the sky. I’m telling you all this so you don’t blame yourself if you’re having difficulty finding the comet. Thick air and moonlight are the culprits.

That doesn’t mean you shouldn’t try for it. You can wait until early twilight when the comet’s higher up. The brightening sky will eventually compromise your view, but fuzzballs as bright as ISON (now around magnitude 5) aren’t too hard to see in early dawn light. The advantage here is that the comet is higher.

Don’t expect to see much of a tail in binoculars at this time unless ISON has another major surge. Recent reports from amateur astronomers using 10×50 binoculars indicate the tail is dim or invisible due to the double whammy of twilight and moonlight.

The moon will be with us until twilight gobbles up ISON, so views of it will be comprised until some days after perihelion when it once again becomes visible in a dark sky. Assuming the comet has survived the sun’s heavy-handed cooking, it should return bright and glorious.

Courtsey - Astro Bob http://astrobob.areavoices.com/

Saturday, November 16, 2013

All-sky finder chart for C/2012 S1 (ISON)

All-sky finder chart for C/2012 S1 (ISON)


Courtesy - in-the-sky.org

Weekly Ephemeris for Comet C/2012 S1 (ISON)

| Ephemeris for Comet C/2012 S1 (ISON)

| Date                  RA              DEC           Mag      Constellation
| 2013  11  15 |   12  52  01 | -06  46  58 |  5.64 |  | Virgo
| 2013  11  22 |   14  15  46 | -16  15  41 |  3.84 |  | Virgo
| 2013  12  01 |   16  18  43 | -13  55  57 |  1.19 |   Scorpius
| 2013  12  08 |   16  10  51 | -00  36  17 |  4.02 |  | Serpens Caput
| 2013  12  15 |   16  09  47 | +14  48  57 |  4.86 |  | Serpens Caput
| 2013  12  22 |   16  13  38 | +35  32  26 |  5.33 |  | Corona Borealis
| 2014  01  01 |   16  38  10 | +70  55  00 |  6.18 |  | Draco
| 2014  01  08 |   00  03  56 | +87  08  47 |  7.02 |  | Cepheus
| 2014  01  15 |   03  39  51 | +74  38  22 |  7.88 |  | Camelopardalis
| 2014  01  22 |   03  59  40 | +65  33  57 |  8.67 |  | Camelopardalis
| 2014  02  01 |   04  14  39 | +57  16  32 |  9.65 |  | Camelopardalis
| 2014  02  08 |   04  23  20 | +53  24  34 | 10.25 | | Camelopardalis
| 2014  02  15 |   04  31  37 | +50  31  16 | 10.78 | | Perseus
| 2014  02  22 |   04  39  48 | +48  18  02 | 11.26 | | Perseus
| 2014  03  01 |   04  48  00 | +46  33  09 | 11.70 | | Perseus
| 2014  03  08 |   04  56  16 | +45  08  58 | 12.09 | | Auriga
| 2014  03  15 |   05  04  35 | +44  00  16 | 12.46 | | Auriga
| 2014  03  22 |   05  12  57 | +43  03  18 | 12.79 | | Auriga
| 2014  04  01 |   05  24  59 | +41  57  01 | 13.23 | | Auriga
| 2014  04  08 |   05  33  25 | +41  18  38 | 13.51 | | Auriga
| 2014  04  15 |   05  41  52 | +40  45  18 | 13.77 | | Auriga
| 2014  04  22 |   05  50  16 | +40  15  58 | 14.01 | | Auriga
| 2014  05  01 |   06  01  02 | +39  42  52 | 14.29 | | Auriga
| 2014  05  08 |   06  09  21 | +39  20  01 | 14.50 | | Auriga
| 2014  05  15 |   06  17  34 | +38  59  13 | 14.69 | | Auriga
| 2014  05  22 |   06  25  41 | +38  40  08 | 14.88 | | Auriga
| 2014  06  01 |   06  37  06 | +38  15  22 | 15.11 | | Auriga
| 2014  06  08 |   06  44  55 | +37  59  35 | 15.27 | | Auriga
| 2014  06  15 |   06  52  35 | +37  44  58 | 15.41 | | Auriga
| 2014  06  22 |   07  00  04 | +37  31  27 | 15.54 | | Auriga
| 2014  07  01 |   07  09  24 | +37  15  43 | 15.70 | | Auriga
| 2014  07  08 |   07  16  25 | +37  04  50 | 15.82 | | Auriga
| 2014  07  15 |   07  23  12 | +36  55  10 | 15.93 | | Auriga
| 2014  07  22 |   07  29  43 | +36  46  51 | 16.02 | | Auriga
| 2014  08  01 |   07  38  32 | +36  37  32 | 16.15 | | Lynx
| 2014  08  08 |   07  44  19 | +36  33  02 | 16.23 | | Lynx
| 2014  08  15 |   07  49  45 | +36  30  23 | 16.31 | | Lynx
| 2014  08  22 |   07  54  49 | +36  29  46 | 16.38 | | Lynx

Courtsey - In-The-Sky.org

Friday, November 15, 2013

Stop Press!! Comet ISON

Comet ISON has an outburst!

“We simply urge everyone who can to get out and observe it while they can.”

Comet ISON brightened substantially last night and may be becoming visible to the eye alone, in a dark sky.  It could be that the comet is now simply finally “turning on."  Or this could be a temporary brightening, meaning the comet will fade again in a day or two.  Or the comet's nucleus could be fragmenting.  The comet is headed into the morning twilight now, as it hurtles toward its perihelion, or closest point to the sun, on November 28. Morning twilight is beginning to interfere with observations of Comet ISON, so if you’re going to search, grab your binoculars for scanning the eastern sky before dawn … and do it soon!

OT- Comet Lovejoy image

Comet Lovejoy image taken by Rishabh Jain, Sr. Educator at SPACE

Path of ISON from Nov 15th to 27th

Path of ISON from Nov 15th to 27th

Click on the image to see full resolution image

Comet ISON Comes to Life!

Comet ISON Comes to Life!

Veteran comet observer John Bortle reports that Comet ISON is undergoing a major outburst. It was six times brighter when he observed it on morning November 14th than on the previous morning.


Comet ISON on November 10, 2013
John Vermette of Tucson, Arizona, photographed Comet ISON on November 10th, before its recent outburst. Click above to see higher resolution versions of this and other photographs in our Comet ISON gallery.
John Vermette

Bortle noted a short, faint tail while viewing the comet through 15×70 binoculars. At least one observer has reported seeing the comet without optical aid.

Bortle comments: "Just what this event signals for the future of C/ISON, with it now exactly two weeks from perihelion, is difficult to say. Over the next few days it should become apparent whether this event is the result of a single massive release of new volatiles; the nucleus having fractured; or perhaps even a dramatic permanent, sustainable, uptick in the comet's overall brightness."

The predawn sky also boasts another bright comet: Lovejoy C/2013 R1 — not to be confused with the famous sungrazer C/2011 W1, which was also discovered by Terry Lovejoy. Comet Lovejoy is currently roughly equal to ISON in brightness, and it's much better placed for observers in the Northern Hemisphere, above the constellation Leo.

The Moon will be lighting up the morning sky starting November 16th, but both comets should be bright enough to shine through the moonlight. Lovejoy should remain visible all month long for northern observers. ISON, by contrast, is rapidly approaching the Sun, so it's visible only low in the east just before the sky starts to brighten — and getting lower every morning.
Courtesy - Sky and Telescope

Thursday, November 14, 2013

Comet C/2013 R1 Lovejoy makes an appearance as well as ISON
Comet Lovejoy is one of 4 comets currently visible in the sky  along with Comet ISON, C/2012 X1 Linear and Comet 2P/Enke.

The brightest and best placed comet for morning viewing is currently Comet C/2013 R1 Lovejoy. Shining at +6th magnitude, R1 Lovejoy just passed into the constellation Leo after a photogenic pass near the Beehive Cluster (M44) in Cancer last week.


Comet Lovejoy, formally designated C/2011 W3 (Lovejoy), is a long-period comet and Kreutz Sungrazer. It was discovered in November 2011 by Australian amateur astronomer Terry Lovejoy. The comet's perihelion took it through the Sun's corona on 16 December 2011, after which it emerged intact and continued on its orbit to the outer Solar System.


As Comet Lovejoy was announced on the 16th anniversary of the SOHO satellite's launch it became known as "The Great Birthday Comet of 2011", and because it was visible from Earth during the Christmas holiday it was also nicknamed "The Great Christmas Comet of 2011"

In space, the comet first became visible to the STEREO-A spacecraft on 3 December, and to the SOHO spacecraft on 14 December. As the comet approached the Sun it was observed by eighteen instruments on six satellites: STEREO-A and -B, SOHO, SDO, Hinode and PROBA2.
Comet Lovejoy captured using T3 Itelescope by SPACE on Nov 12th 2013


Comet Lovejoy captured using T3 Itelescope by SPACE on Nov 12th 2013


Comet Lovejoy reached perihelion on 16 December 2011 at 00:17 UTC, as it passed approximately 140,000 kilometres (87,000 mi) above the Sun's surface. Before perihelion, the nucleus of Comet Lovejoy had been estimated to be between 100 and 200 metres (330 and 660 ft) in diameter. Since the comet survived perihelion, it is thought that the nucleus must have been larger, perhaps up to 500 metres (1,600 ft). During the coronal passage, it is believed that a significant fraction of the comet's mass was burned off.


Unlike comets Encke and ISON that are plunging near the Sun, Comet R1 Lovejoy never gets closer than 19 degrees elongation from our nearest star in late December. It also reaches a maximum northern declination of 43 degrees on November 28th, the same day that ISON reaches perihelion. For mid-latitude northern hemisphere observers, R1 Lovejoy will remain well placed at 35 to 45 degrees above the northeastern horizon about an hour before sunrise through late November.

Here are some key dates to aid you in your quest to spy Comet R1 Lovejoy in late November:
November 11th: Passes near +4.5 Kappa Leonis.
November 14th: Passes from Leo into the constellation Leo Minor & passes near the +5.3 star 20 Leonis Minoris.
November 16th: Passes near the +5th magnitude stars 28, 30, and 34 Leonis Minoris.
November 18th: Passes into the constellation Ursa Major.
November 19th: Passes near the +4.8 magnitude star 55 Ursae Majoris & +5.3 magnitude star 57 Ursae Majoris.
November 19th: Closest to Earth, at 0.4 AUs distant.





Path of Comet Lovejoy in the sky

How to Photograph Comet ISON?

Now since the closest approaches of comet ISON is 15 days away and still it is expected to become visible to naked eyes in the dawn, it is time for us to take our camera and take some pictures of the night sky so as to brush up our knowledge and hands on experience is astrophotography.
If you’re excited about this comet – and I’m guessing you are, or you wouldn’t be here! – Then you probably won’t be content to just look at other people’s pictures and you’ll want to take some photographs of them yourself to enjoy in years to come. But how? Isn’t “astrophotography” hard? Don’t you need huge lenses? And complicated, mega-expensive cameras?
No, no, and no.
If this comet is bright enough to be easily visible to the naked eye, which we think/hope it will be, then taking their celestial portraits will actually be pretty easy. In fact, you’ve probably got all the gear you’ll need to do that already! 
Taking images of the comet ISON will require a few essentials.
  • A camera (well, isn’t that obvious) with its accessories.
  • A Tripod
  • Somewhere with a clear, unobstructed view of the comet (East Direction as it is rising at 4 am in the morning)
  • A camera release cable for long exposure and also to avoid shake to the camera while clicking the shutter button.
  • Let’s look at each of those in turn.

CAMERA:
If the comet is bright enough to be easily visible to the naked eye, then the camera you already own will probably do the needful. I assume that your camera is a digital one  with full or partial manual control (if you’re still using a film camera don’t worry, you can still take photos of the comets, and most of this post will still be relevant to you).
Oversimplifying it horrendously, I know, there are two types of digital cameras basically – compact cameras (which are fitted with just one lens, that may or may not zoom in and out), and digital SLRS (the more expensive, heavy ones which let you use different lenses).  As long as your compact camera is slightly more advanced than a simple “point and shoot” one, i.e. it has different settings for things like landscapes, portraits and sport, and has a flash that can be turned off, you will be able to photograph the comets with it, if they get nice and bright. If you have a “DSLR” then you will be able to take pictures of the comets regardless of whether they attain naked eye visibility or not, because you’ll be need to take exposures long enough to capture enough light to get a picture.
So, assuming you have a “decent” camera, what else do you need?


SOMETHING TO HOLD IT STEADY
One cannot take a long exposure just by holding the camera in your hands. It will be very shaky and tiring. Which is why, a good, sturdy tripod is required. Why do you need something to hold your camera steady, because unless the comet in question is blazingly bright in the sky, you simply won’t be able to hold your camera steady enough in your hands to get good pictures of it. Any unsteadiness, any camera shake will result in a blurry, pretty rubbish picture.
 Thankfully, most cameras now have a threaded hole in their bottom which allows you to put them onto camera tripods, which are brilliant for astrophotography because you absolutely MUST keep the camera steady while photographing the sky. If your camera has a thread for a tripod, that’s brilliant, you’re halfway there! If your camera doesn’t have a hole for a tripod screw, then you can always try cobbling together something with tape or whatever to fix your camera to a tripod, or get a kind of “clamp” from your local camera shop which will hold your camera steady and screw onto a tripod, but…
What? You don’t have a tripod? Well, my advice would be to go and get one, as soon as possible, you’re really going to need one when ISON appears, trust me! But if you can’t right now, for whatever reason, then what you can do is use a bean bag to keep your camera steady. You place the bean bag on a wall, or the top of your car, or whatever, then put your camera on it and push it down until it’s held securely in the bag. There. That’ll do. It’s all about avoiding camera shake you see, and a camera on a bean bag is a lot steadier than a hand held camera. In fact, it’s very, very unlikely that handheld cameras will get very good pictures of the comets.
Ok… camera… being held steady… next?

CLEAR VIEW OF THE COMET
This might seem like common sense, but think about it. Are you sure, and I mean sure, that you’ll be able to see these comets from where you live, from your garden or nearby street? Are you sure that that tree over there won’t be in the way? Are you positive that the nearby building won’t be in the way..?
You need to do some research. Use the charts on this blog to assess the comets’ visibility from where you live. Chances are that although you might be able to see them, you won’t be able to see them WELL for a number of reasons. That means finding a more suitable viewing – and photographing – location. Maybe your local park will do, because it offers a view of more of the sky? Or maybe the school playing field up the road will do? But places like these suffer a lot from light pollution, so photos you take there will probably suffer from orange glare and flares, which could ruin them. I’d definitely recommend scouting out a few locations out of town, away from the streetlights, advertising lights and security lights. Maybe a farm gateway, or a lay by, or a quiet country road people hardly use? Find somewhere like that, with a clear view of the sunrise sky for, a clear view all around for ISON.


RELEASE CABLE
The release cable is very important in case you are taking a long exposure as the release of shutter for clicking the picture is attached to the camera and while clicking shots at regular intervals will lead to shake in camera. If we use auto timer in the camera or if we put for a delay then the problem will be solved but it will be a tedious task for the photographer. We can use a USB cable and connect a laptop to the camera so as to take pictures from a distance without touching the camera. In case of a film camera, a release cable is used to take pictures without touching the camera. The purpose remains the same and also the function of the cable. If one wants to take a good shake free picture of the comet, it is very necessary to use a release cable or remote shooting method for the same.
I would suggest you to first arrange these materials and then try to take some pictures of the sky and objects in low light and see how things work. Framing of the comet is necessary and hence you need to find some nice foreground in order to make the image look attractive and better. Also the comet can be compared in terms of size and magnitude if we have some foreground object and some known stars in the field. This way you can use the image and extract some science out of it as well.

Soon this page will have link to a public folder where you can share your images and also get expert comments on that about the quality of the images and how to improve it in case there is some problem. Also in the comment section you can ask questions related to “How to Photograph this comet”. Next week another article on How to photograph this comet with suggested settings of the camera will be featured. Till the time enjoy trying and practicing.

Thursday, November 7, 2013

Comet ISON today - animation froM images taken by SPACE

Comet ISON animation from 3 images taken at 11:30 UT today from New Mexico, USA, T4 Telescope at Itelescope facility under "Internet Telescope Project" being run by SPACE

Friday, November 1, 2013

Comet ISON today clicked by SPACE team


Taken with T4 telescope at ITelescope facility at New Mexico, USA under the "Internet Telescope Project" being run by SPACE