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C/2011 L4 (PanSTARRS) update

Over the past few days the weather across the UK has been patchy but many people have been able to see this comet and we have received some excellent images. Even though the comet is fading it is becoming easier to see as it moves higher into the western sky. A chart showing its position an hour after sunset is included in this Journal article.

The comet is now high enough that it can be seen or imaged in a darker sky. This allows stars to be included in the images so it is possible to estimate the comet’s magnitude. Using a V filter Richard Miles estimated the magnitude as +0.8 on the evening of March 14 so it probably didn’t quite reach mag zero at perihelion but it wasn’t that far away from some of the more reasonable predictions from earlier in the year.

2013 March 17. 80mm ED Apo + Canon 1000D, 10s at ISO1600, Denis Buczynski

The widefield view in the twilight is still impressive and the comet’s broad dust tail is clearly visible in binoculars. Many people have now reported that the comet is an easy naked eye object if you know where to look.

2013 March 17. 1905UT. Canon 500D at ISO800. 60mm lens. Damian Peach.

The view from space is even more impressive. The comet has been visible in the STEREO-B Heliospheric Imager. This is a camera which takes 20×20 degree images of the space between the Sun and the Earth. In these images the comet has a spectacular dust tail which shows much structure. We can’t see most of this from the ground at the moment but some observers are picking up hints of it. Michael Jäger has probably obtained the best result so far as you can see in this amazing picture.

2012 March 12, 2329 UT. STEREO-B HI image. 1200s exposure, unsharp masked. The bright object top right is the Earth.

Denis Buczynski has uploaded many of the images to the Comet Section gallery. Please keep sending your observations to but please could imagers follow the instructions here. Images should have names like 2011l4_20130317_1904_dgb.jpg. We receive lots of images with names like panstars.jpg and these will need to be renamed to the correct format. This requires a lot of work, particularly when we receive dozens of images a day.

Keep watching this comet. You never know what it will do next.

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