SPACE.com's Skywatching Columnist Joe Rao called it "one of the rarest of all cometary spectacles."
Omens – good or bad?
Great Kings, Cesaer, Harold died a year after Halley. C, http://www.geocities.com/Athens/Olympus/6745/haleyhome.html
Nuremberg Chronicles at an Art Exhibit at the Smithsonian Air and Space Museum in Washington, D.C., entitled: "Fire and Ice - A History of Comets in Art" The copy is in the Library of Congress collection
Giotto di Bondoni, painted the return of Halley's Comet in 1301 as the star of Bethlehem in his Nativity fresco, shown below.
Crash into Jupiter and
The hairy visitor – The word comet came to the English language through Latin cometes. From the Greek word komē, meaning "hair of the head," Aristotle first used the derivation komētēs to depict comets as "stars with hair."
Do your homework –know your subject - Caught napping. Ordinary photo in paper – reminder of seeing halley’s –
What is it - http://www.solarviews.com/eng/comet.htm
perihelion on January 12th, due to pass just 0.17 astronomical unit from the Sun (half Mercury’s distance). But it has recently been lurking beyond the Sun, as seen from Earth, so the prospects for a bright comet were difficult to assess until the start of this year.
passes almost between Earth and Sun. For example, Joseph N. Marcus has assessed the degree to which the comet’s gas and dust will forward-scatter sunlight
Afterall been lurking below the horizon with the Northern hemisphere was getting excited. It’s already as bright as the brightest stars, but it is also sticking close to the glare of the Sun. For this reason the general public won’t be gathering on street corners to gaze at it, as they did Comet Hyakutake (in 1996) or Comet Hale-Bopp (1997).
No idea - Brightest since 1965
McNaught has become minus 5 on an astronomers brightness scale in which smaller numbers are brighter and negative numbers are the brightest of all. Venus shines at minus 4, brighter than any star. The full Moon is minus 12.7.
life goes on, miss seeing it, no priority.
Guilt – someones else waiting. Sometimes there is no time for justification or priorities – window of opportunity only so big. Get it in the ‘can’, then rearrange your life. For all the problems you have caused.
Projection on sky – context in universe – massive tail – clear space –overwhelming
Silence, distant lights. Scale, our insignificance under it.
We are all collectors of some kind. Just need to have more than one.
Focus on phenomina, atmospheric effects, cosmos, what next telescope, scuba gear under sea, aerial perspectives, brockenspectre – what can surpass a comet. Inconceivable. haileys Expected but unexpected spectacle. Compulsion – absolute priority
Stays put, one factor improvement over aurora. Technique development, improvement over film. – just keep on trying.
Star trails – meteors - spacecraft
The last comet to get this type of attention was Hale-Bopp back in 1997. In the days that followed, comet McNaught brightened rapidly. It attained a magnitude of 0 on January 6, -1 on January 7, -2 on January 9, and -3 on January 11.
The comet was at its brightest on January 13 and 14. - Observers typically estimated the brightness as -5 to -6 and many were able to easily spot the comet in broad daylight just by blocking the sun with their hand.
Poised in space between the Earth and Sun, SOHO ceaselessly watches the Sun and objects that pass nearby.
The comet entered the field of the Large Angle and Spectrometric Coronagraph (LASCO) camera aboard the Solar and Heliospheric Observatory (SOHO) on January 12. SOHO is orbiting the sun, not far from Earth, and has been imaging the sun 24 hours a day since 1996. It has photographed some of the brightest comets of the last 10 years, but when comet McNaught entered the field of view it was obvious that this was the brightest comet seem by SOHO. An image from SOHO is also displayed below.
Copyright © 2007 by the Solar and Heliospheric Observatory (SOHO)
In this image from SOHO taken on January 14.50, the sun is at the center of the image and blocked by an occulting disk, while the comet is located near the lower left of the field with the tail streaming upwards and to the left. The brightness of the comet's head is strongly saturating the pixels of the CCD chip which causes the horizontal spikes. For comparison, Mercury is located just below and to the right of the comet's head.
Following its closest approach to the sun, the comet moved into the evening skies of the Southern Hemisphere and developed a spectacular tail that was being compared to comet West during March of 1976. Experienced visual observers were reporting that comet McNaught was between magnitude -2 to -3 on January 17, while the tail was 5 degrees long. The comet finally faded to magnitude 0 by January 22. As the comet climbed out of evening twilight, the tail became much more apparent. Terry Lovejoy (Queensland, Australia) estimated the tail length as 15 degrees on January 18, while Andrew Pearce (Western Australia) gave it as 20 degrees on January 19, and 24 degrees on January 21 and 22. Photographs began showing striae or luminous bands in the tail on January 17, while Lovejoy said the striae were visible to the naked eye on January 18. Jim Gifford (Bridgetown, Western Australia, Australia) estimated the naked-eye tail length as 35 degrees on January 23, 31 degrees on January 24, and 30 degrees on January 25.
It's really getting cooked
Cornering the Comet.
22 January 2007
Ruben’s text message triggered my well practiced ‘fireman drill’ routine to get beyond the city lights asap. Marthy, was close behind. In the street we stopped dead -gob smacked by the big bright visitor hanging there in the sky. We were driving nowhere!
A photo of Comet McNaught in the newspaper the previous week did nothing to excite me about the merits of photographing it. Remembering the faint fuzz ball we saw of Haley’s Comet, I figured that even a giant telescope would yield an image for passing interest only. The cloudy nights that followed added little disappointment.
Little did I know how acute my time would be and how over the next 48 hours I would be wound up in a once-in-a-lifetime chase even using a super wide angles lens to capture the enormous scale and wonder of a comets tail in our southern sky.
My get-the-photo instinct snapped in. Before any clouds could possibly re-gather, my camera was setup in a shadow, away from the flare of street lights and I made my first ever photographs of a comet - a totally unexpected crowning addition to my collection of phenomenal phenomena photos.
Low light photography technique.
I knew from photographing the aurora, exposure time needed to be very short or the stars (and therefore comets) would trace annoying streaking lines as they slowly rotate in the night sky. This is most noticeable with long lenses covering small parts of the sky, so telephoto lenses need to be used with exposure times of less than 5 seconds where 15-30 seconds may be tolerable for wider lens.
The trade-off is to use lenses set with wide-open apertures and suffer the noticeable distortion and lens flare. Sensor ‘noise’ will also have to be tolerated as the ISO rating may need to be set as high as 1600. At this extreme, advantages of camera expense really shows. Large mega pixel sensors help to reduce the pixel size of the noise, and big fat lenses full of fast glass are essential to let in every last photon of the faint light.
Wide open lenses means very shallow depths of field, which means a critical focus problem - the longer the lens the great the problem. Auto focus is unlikely to assist in such low light and the problem gets worse as you cannot see enough detail to manually focus the lens. Any slight error and stars render into unseemly blotches.
My Canon lenses also focus past infinity so I cannot simply rotate the focus ring until it stops. Tape from the first aid kit (also a camera bag item) comes in useful here to fasten the focus ring once critically focused. Remember to keep a torch in your camera bag too. Your only remaining chance for sharp focus may be the use of the distance calibrations on the lens barrel to manually set the lens on infinity. Remember to turn of the auto focus though, or the lens will ignore your setting and go ‘hunting’ again. With telephoto lenses I often find precise setting of this infinity mark to be still a bit of a guess and I have been able to use auto focus on the moon or some very distant light on the horizon, switching off the auto focus before recomposing.
The nice thing about digital cameras is that images can be progressively checked for focus etc. on the LCD screen. Comets, as fast as they are, are not going to rush off the scene, so I sometimes took the luxury of downloading to my notebook computer for fuller examination.
Another thing to check is that lens with image stabilizers are turned of when used on tripods – otherwise the lens elements will shake inside and you will be worrying about some crazy star trails – believe me I have done it.
Tonal range and contrast can also be problems especially if any foreground is lit by moonlight or other light. Separate exposures can be made for each area of differing brightness, and merged later as masked layers in software such as Photoshop. I find shooting in RAW format is essential as I am able to capture several more ‘f stops’ outside of the normal tonal range of the Jpeg image format. This can be recovered with appropriate computer software.
Fastidious computer processing is also critical to reduce the effect of noise and correct lens vignette and aberration and to keep up the colour intensity. Despite all this, many of my images will not pass close-up scrutiny. Amazing as the technology is, there are still limitations. But hey… we would not have got anything like this a year or two ago either.
I’ll live with that.
Inevitably the clouds encroached but a long lens and teleconverter (400mm) allowed me to pick out the comet from among them. To my surprise I soon found this very excessive. As the sky dimmed the tail grew. Lens focal length rapidly shortened to get it all in. After dodging the clouds, it dawned on me that they may even add something, giving something other than stars for a sense of scale and presence.
Delighted to have some images ‘in the can’ it was time to venture out and find a horizon, preferably a well known landmark on our mountain backdrop. Marthy took the wheel and we instinctively drove to the nearest and clearest view Southwest. It must have been a good choice as quite a crowd was gathering. I stood my tripod by several others who obviously had the same ideas of the best viewpoint. As I busied myself with the task of composing, focusing and cursing the cloud, a serious conversion arose about the problems of night sky photography. Those with basic cameras must have been beyond straining point.
It was all very social and the odd voice was soon recognized in the darkness, friendships renewed leading to wide conversion about the cosmos and beyond. Comets come and go every year, but few glow this bright for decades. I learnt this one was taking an extra-ordinary frying, looping in front of the Sun within the orbit of Mercury. Apparently this one does this every 85,000 years or so, swinging in from freezing darkness, way beyond our solar system. Basically, this thing is nothing but a dirty snowball the size of Mt Everest, vapourising in the solar wind yielding a small bucket load of dust, blown away from the sun as flails of glowing gossamer for a mere million kilometers.
Such a simple thing but easily supersedes my notion of the aurora being the greatest show on earth. No wonder comets have created such wonder, inspiring countless civilizations into endless ponderings and prophecies.
Usually comets are considered unlucky, or with some stretch of imagination, terrestrial invasions. Not everyone seems preoccupied with prophecy though.
Some early civilisations probably saw comets as just hairy looking things in the sky. Afterall, the Greek word komē, means "hair of the head”. But then,Aristotle did use the derivation komētēs to depict comets as "stars with hair." Apparently he thought a fair bit about things, so maybe there is more to it than this. He reckoned comets were an atmospheric effect. Great thoughts at the time but these were found to be wrong by the 16th centuary by s Danish astronomer Tycho Brahe who determined the comet he and others were measured were four times distant than the moon. Too far away to be of our atmosphere’s doings.
Seeing the comet hanging there poised for plunging, I easily thought of the ancient Greek story of the Sword of Damocles, and its reminder doom to any power-broker. Was oath breaking King Harold shaken to his own failure and death after being warned of by an ‘evil star’ - a great ball of fire with a flaming tail in 1066. “Isti mirant stella” – “they wondered at a star” it says on frame 33 of the Bayeaux Tapestry. This may seem a little flippant but I would have done more than wonder knowing the Norman fleet was coming.
Astronomers must also have philosophical moments too. I was intrigued to learn that Robert McNaught, discoverer of this comet, used this very concept to name an asteroid he discovered in 1991. ‘5335 Damocles’ has the probability of crossing earths orbit some day. This was the first discovered Damocloid class of asteroid believed to be the nuclei of Halley type comets, now the darkest of all objects in the solar system having ‘outgased’ themselves. Sounds more like something for politicians than power-brokers!
Today we are more concerned about these things colliding with Earth. This would certainly be bad luck and would take out more than just those in positions of power.
No wonder we have had such preoccupation about comets, and to prove it our modern day powers-that-be have justified many taxpayer dollars sending spacecraft out just to tail and crash into them. And what for? Just to say we can? So we can finally say we have the power over territorial visitors and we aren’t scared anymore?
It seems Saturn, and more particularly, Jupiter are good allies in our wish to corner comets. They do have great power to gradually pull them in during each infrequent orbits and dispose of them, once and for all. In 1994 the comet Shoemaker-Levy showed the whole world live, how fallible comets really are - this one was certainly not going to shatter human lives. Caught by Jupiter’s gravitational force, it circled for a few years, broke into 21 pieces eventually peppering the stormy Jovian atmosphere with a week of gargantuan fireballs, detected from earth.
This animation - Impact A Fireball, from Calar Alto Observatory ftp://seds.lpl.arizona.edu/pub/astro/SL9/animations/cao_a1.mpg
- would have helped Aristotle’s comprehension of comets greatly improving his long term credibility.
Other comets are known to have wound in closer to the sun becoming ‘sun grazing’ and either self destruct, plunging into the sun or throw back out to Saturn and Jupiter as scraps for annihilation.
With these big garbage disposal units in our sky, do comets become dog tucker and nothing for us to be afraid of? Not quite, apparently. The moon shows the odd chain of craters suggesting Earth is a comet catcher too. The impact of just a fragment of one would wipe life of the surface of Earth. Hmmm.
Fortunately others only see only good in comets. When seen horizontally across the sky in a comet can easily be construed as a traveller, a messenger or even a pointer. The “Star of Bethlehem” my well have been a comet and giving us a lot to hope for. Giotto di Bondoni must have thought so as he painted the return of Halley's Comet in 1301 as the star of Bethlehem in his Nativity fresco.
Two millennia later, this ‘star’ is still seen a promise of good times to come: peace and goodwill to all mankind. Hardly a doomsday story, but until everyday is filled with peace and goodwill, everyday is effectively a doomsday!
Upon previewing one image I noticed I had a photographer loom up in the foreground, having been barely visible to the naked eye. About to move location for a clearer view I hesitated and decided to keep him in view to add human perspective. Later I was able to recognize him and show him this image
This made me realize A good photo would require not just a skyline but an entire foreground. We headed of into the country in search of one, only the clouds were soon again beating us to it. I used a wide angle lens to get all the cloud in as well, for just the fun of it or was that for some extra sense of satisfaction. Sometime after midnight we conceded and went home.
The night’s shooting had to be reviewed before sleeping even in he early hours of the morning. I was extremely surprised to how much tail could be seen with such a little amount of highlight adjustment. Through the cloud, just above the horizon, was a huge half circle of radiating trails of light. Our eyes barely detected it but real it was. This was just amazing.
Very curious now, I did quickly searched the internet for images of this comet and became totally blown-away with several, clearly showing the same amazing extent but set against a deep glowing evening sky. Just stunning!
"Comet McNaught had it's nearest brush with the sun and became visible only to Southern Hemisphere sky-watchers. Right now the 6.2-mile-wide (10-kilometer-wide) comet is about 74.5 million miles (120 million kilometers) away from Earth and is traveling at nearly 62 miles (100 kilometers) a second. The once-in-a-lifetime view would last for a few more days."
23 January 2007
That did it! I had a very serious task on hand. But the cloud remained… all next day and looked to stay for quite a while.
A friend suggested a trip to the high country, away from this South-Easterly cloud build up A striking and well known foreground was needed too. Checking the map for likely comet alignments, only one real option was found: the lights of Tekapo village pillared over the lake water. After several checks of weather satellites and Tekapo webcam views, clear skies were assured and by 10:20pm Hamish, Angela, Marthy and I were on the eastern shore of LakeTekapo standing under endless myriads of shimmering stars in pitch blackness, awfully silent, as the comet began its nightly descent into visibility.
Two hours quickly passed with frantic experimentation and a search through the dark scrub for a clearer foreground view. I had thought my 50mm standard lens with a f1.4 aperture would be then most logical lens to use, but the pinpoints of starlight were flaring badly. Suspecting focus problems I persevered to no avail. My 24-105mm zoom fared better but at f4, exposure was far too slow with star trails starting to show. Dispensing with this it was the 17mm-35mm zoom that saved the day. At f2.8, corner distortion could be tolerated and exposures were still possible within 30 secs even though the night had darkened very deeply.
The comet crawled down lower, skimming slowly across the line of Tekapo lights. Finally it dipped below, leaving its huge fantail to flag its whereabouts for the remainder of the night.
24 January 2007
The next night showed prospects for a clear night over Timaru. Cars were lining up anywhere there was a clear view of the sky. I left a gathering crowd on the Marine Parade at sundown deciding to go onto the eastern port extension, for a waterfront foreground. Everyone was chatty and I almost got more caught up in meeting interesting people than getting my camera ready. Out of nowhere, patches of cloud appeared, threatening any view, but up there the comet entered like an apparition. Back on the Marine Parade, cars were leaving as the last glow in the sky grew very hazy. We were being fogged out. I headed home to study the weather and took a punt on going up the coastline for a southwards view of the lights of the port and Timaru.
The lights lit the air above in a dark orange haze, making any clear view of the comet seem impossible, but there, despite the brightness the comet shone out, hanging high above. The fog drifted in and out but shots were possible amidst frantic bouts of camera and lens cleaning. Finally the breeze changed to the west sending warmer puffs of air for a respite to the heavy condensation.. Past midnight, the comet swung lower and lower into the orange haze remaining incredibly clear. I can only assume the scatter of light was intensifying the light of the comet tail. The telephoto lens could easily be used at f2.8 to pick out landmarks like the port cranes and clock tower with the corona of the comet careening closely above. The impact was striking and I realized there was enough brightness to use the teleconverter at its minimum of f5.6. Now the comet appeared to be zooming along. It finally blended with the glow of the strong port lights.
Thinking it was about to set I packed up feeling very satisfied with my night out. Heading home I realized it was not going to go below the horizon at all, so I made for the dark side of town, in time to see it weaken from in the heavy atmosphere beyond the Jacks Point Lighthouse.
I went inland in search of higher ground and became absolutely fog bound. The higher I went the thicker to fog. It was then a toss up to stay out for pre dawn shots or go home and get some sleep. Figuring fog usually gets worse towards morning I opted for the sleep.
A week later
Our summers are usually full of clear sky but this one was nothing but a series of southerly cold fronts and air flows totally clouding our sky. It was to be a week before we could see stars again, and still heavy patches of cloud persisted which the moon shone through forming a corona.
Even with a full moon the comet was unexpectedly visible although the tail had diminished. Trying again I discovered how well my camera could perform in the moonlight – until it clouded in again. Next night started off slightly better, but mist was soon forming, running like a waterfall down the steep western side of Mt Horrible. As I watched the moon rise over the Pacific Ocean, the mist pooled in every low lying place offering a new photography challenges. Eventually it thickened crawled up the hillsides and drowned the landscape. Once again, I was driven home by cloud.
Chances of moonlit scenes with comets were diminishing and I made one final dash out the following night for a much needed view for a photographic project associated with Mt Horrible. It was still very dark. Even as the moon rose, one minute exposures were required to see the land properly. Tiring of waiting for the cloud to show a glimpse I set the camera on interval timer and worked on my notebook while waiting. Without realizing this neat little animation came about.
What a special two weeks. Expected but unexpected spectacle. This was not a time to consider any other priorities. I will cherish these very rare sights dubbed the rarest of all cometary spectacles." Unlikely to be repeated in my life time this had to be my most prized capture of all photographic phenomena.
In the euphoria I felt I had not cornered a comet but conquered it.
-2 to -3
moved into the evening skies of the Southern Hemisphere. luminous show bands in the tail.
Moves above evening twilight, and the tail became much more apparent. Striae visible
Comet McNaught had it's nearest brush with the sun and became visible only to Southern Hemisphere sky-watchers. Right now the 6.2-mile-wide (10-kilometer-wide) comet is about 74.5 million miles (120 million kilometers) away from Earth and is traveling at nearly 62 miles (100 kilometers) a second. The once-in-a-lifetime view would last for a few more days.