THANKS as ISON keeps GIVING!

UPDATE: 10:00 UT

It is clear that a part (reduced or fragment) of the nucleus of Comet ISON made it round the sun and is now moving away from the sun. After initally brightening and reforming a dust tail derived from its momentum as it swung around the sun, it seems to be fading now as it moves towards the outer FOV of the Lasco C3 camera of the SOHO observatory. The tail is gradually swinging around to the outbound direction. It will be interesting to see what the mission scientists can gleen from this from the multitude of data sets.

For now my rule of thumb, is really not very sciency, but if a naked eye comet reaches the Lasco C3 FOV - its going round! Not a lot of math in that, but its two from two in 3 years! Seriously though for the real science - read NASA's Comet ISON observing campaign blog which is being regularly updated by respected comet supremo Karl Battams.

UPDATE: 05:30 UT

ISON continues to brighten and a new dust tail appears to be swinging around from its transit path towards its outbound trajectory.

Image Credit: Solar and Heliospheric Observatory - Lasco C3 23:30 UT 28/11/2013

What we know about comets is alot more than we used to know, but not everything there is to know!

Like most people with a passing interest in astronomy I have been following the passage of Comet ISON as it approached perihelion. I have followed the intense debates about what might constitute a "secular light curve" and observed daily predictions and alerts about what was about to happen.

Today it has been hilarious to see people pronounce ISON dead on arrival at perihelion and wander off to their thanksgiving dinner thinking its all over red rover!

Currently twitter is ablaze with witty retorts and updates as some sort of remenant has re-emerged and continues to brighten. Most of the wise observers are doing the appropriate thing and "waiting for more information". So far on twitter it has been re-named Schrodinger's Comet, Schwartzneger's "I'll be back" comet.

Image Credit: Solar and Heliospheric Observatory - Lasco C2

As for me, I am reminded of Comet Lovejoy (2011) which surprised everyone and made it past perihelion and broke up outbound after a spectacular display at Christmas 2011. I couldn't help remembering that the tail didn't really return immediately after perhelion, until the Comet moved away from the immediate vicintiy of the Sun. In fact in 2011 Lovejoy's tail didn't really reform until it was even further out than it is now.

One thing to consider here is that the perspective from which we view these images is only two dimentional, ie whats in the image, and its very hard to tell from that perspective what at the front or behind.

Image credit: Comet Lovejoy (2011) Solar and Heliospheric Observatory - Lasco C3

Whilst comets are not made of sugar, think of creme brulee, the sugar gets heated up, some smoke comes off, it suffers intense heat, changes its composition and comes out the otherside a crunchy piece of toffee with roughly its same mass but slightly different texture. Now this is a bit of a stretch scientifically as I said, as comets are not made of sugar, but with the heat, the increase in speed, the change of direction, the resultant slowing and cooling after perihelion, there is alot going on there that we really just don't know enough about.

Which is why comets are, always have been, and always will be, incredibly undpredicatable.

Comet Lovejoy's sunny death dive! Strike that - It lives on!

UPDATE: 2011/12/16 11:00 UTC


Oooops....no one told Comet Lovejoy it was supposed to conk out near the sun. It has surprised everyone by surviving the close pass and stunning the SOHO team with their birthday present.

As the saying goes "16 and never been kissed" December the 2nd was the 16th birthday of the SOHO mission and what better way to celebrate than Lovejoy "kissing" the sun and emerging from the other side. Sungrazing comets are so-called because they pass so close to the sun that they rarely survive the passage. Multiple satellite instruments have picked up the comet exiting from behind the sun with its tail gyrating wildly in the solar wind. Latest Lasco instrument photos now show it moving away, still very bright and a partially visible tail that is still mostly obscured by the pixel bleed from the CCD camera.

Comet Lovejoy has lived up to its expectations of being one of the brightest Kreutz Class (Sungrazing) comets of all time.

Blazing at mag -3 and out of view for all "earthbound" observers, it is expected to cease to exist sometime in the next 12-18 hours as it approaches within 1.8 Solar radii.




This spectacular sequence from the LASCO C3 instrument on the SOHO observatory records the final death plunge. Note the horizontal artifact is due to the brightness of the coma which overloads the well count of the CCD camera causing pixel bleed.

In the highly unlikely event that the comet does make it round the sun it will be even more news worthy!

"The SOHO/LASCO data used here are produced by a consortium of the Naval Research Laboratory (USA), Max-Planck-Institut fuer Aeronomie (Germany), Laboratoire d'Astronomie (France), and the University of Birmingham (UK). SOHO is a project of international cooperation between ESA and NASA."

UPDATE: Lovejoy appears to have survived its passage, scientists noting with interest the presence of an Ion Tail in a addition to the dust tail, this has apparently not been seen before in a Kreutz Class comet. SOHO website and NASA having been live blogging and its a little early to know yet if we are going to get a great Christmas comet.