Comet C/2011 L4 (Pan-STARRS)

 

     Comet C/2011 L4 (PANSTARRS) is a non-periodic comet discovered in June 2011 that became visible to the naked eye when it was near perihelion in March 2013. The comet was discovered using the Pan-STARRS telescope located near the summit of Haleakalā, on the island of Maui in Hawaii (U.S.).
     Comet C/2011 L4 had an apparent magnitude of 19 when it was discovered in June 2011. By early May 2012, the comet had brightened to magnitude 13.5, and could be seen visually when using a large amateur telescope from a dark site. As of October 2012, the coma (expanding tenuous dust atmosphere) was estimated to be about 120,000 kilometers (75,000 miles) in diameter.
     The comet was spotted without optical aid on 7 February 2013 at a magnitude of ~6. Comet PANSTARRS was visible from both hemispheres in the first weeks of March, and passed closest to Earth on 5 March 2013 at a distance of 1.09 AU. It came to perihelion (closest approach to the Sun) on 10 March 2013. Original estimates predicted the comet would brighten to roughly apparent magnitude 0 (roughly the brightness of Alpha Centauri A or Vega).
     An estimate in October 2012 predicted the comet might brighten to magnitude -4 (roughly equivalent to Venus). In January 2013 there was a noticeable brightening slowdown that suggested the comet may only brighten to magnitude +1. During February the brightness curve showed a further slowdown suggesting a perihelion magnitude of around +2.
     However, a study using the secular light curve indicates that the comet had a "slowdown event" when it was 3.6 AU from the Sun at a magnitude 5.6. The brightness increase rate decreased and the estimated magnitude at perihelion was predicted as +3.5. Comet Halley would be magnitude −1.0 at the same perihelion distance. The same study concluded that the comet is very young and belongs to the class of "baby comets" (i.e. those with a photometric age of less than 4 comet years).

     Almost missed that one. Those days, when the Comet was the brightest, many attempts been made by local astronomers to catch it, but with no success. Due to the weather conditions and Sand Storm from Egypt, there was always something that will obscure the view of the Comet.

     That is the reason why the sky's on the image is not blue and the sunset is brown, what you see is the actually sand in the air and some thin layers of clouds. It seemed that it was impossible to catch it at all. So, the only reasonable thing to do against those kind of conditions, was to try and get to a higher position and try to shoot above this mess. I was right.​

     Luckily, some half an hour drive from my home, we astronomers got one observation spot, that have some 800 meters elevation above the sea. And that is of course 800 meter less of polluted air to see through.

     Catching that Comet was almost got me frustrated. Because, although condition was much better than in the city, it still wasn't visible to the naked eye and even to 10 x 56 binoculars. We searched and searched, hundreds of shots  and try after try we fail, it simply wasn't visible, not to the eye, nor to the camera.

     Then, as almost always this happens this way, i thought about getting packed up and leave the place, when I told my self to try it one last time. I pointed camera once again to the area where it supposed to be, readjusted settings, set it to 3 seconds exposure and shot for one last frame. And what are you know? Boom, there its was, for the first time in my life i felt like a real Comet Hunter. :-)

     What is left  after that, is to take the advantage of the moment. 

 

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Technical Info:

Optics        :   Canon EF-S 55-250mm f/4.0-5.6 IS II @ 200mm @ f5.6

Camera      :   Canon T3i (600D) Baader Mod           

Mount        :   Tripod​

Guiding      :   No guiding            

Acquisition :    In Camera   

Exposure    :   3 seconds 

Stacking     :   No stacking

​Processing  :   Photoshop

 

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                                                                    And some Animation :

 Copyright  © 2019  Sergio Kaminsky. All rights reserved.