A group of amateur astronomers have become the first people to observe the so-called tenth planet 鈥淴ena鈥� through a telescope鈥檚 eyepiece, and not the original discoverers.
The amateur group, mostly from the St Louis and Rockland Astronomical Societies in the US, first determined where Xena should be on 9 October 2005. They then used the 2.1-metre Otto Struve Telescope at McDonald Observatory in Fort Davis, Texas, to catch a peripheral glimpse of the distant and highly inclined world. They released news of the sighting on Monday.
The existence of Xena was first revealed in July 2005, by Caltech鈥檚 Mike Brown and colleagues. They pinpointed the object, officially called 2003 UB313, by examining a series of images captured by an automated camera and telescope in October 2003. It lies about 13.5 billion kilometers from the Earth, about 90 times the distance between Earth and the Sun.
Advertisement
But the members of Brown鈥檚 team did not observed Xena the old-fashioned way 鈥� through a telescope鈥檚 eyepiece.
Faint star
Louis Berman, a member of the St Louis Astronomical Society and the second observer, describes what he saw as 鈥渁 very dim, point-like source that could only be seen through averted vision. If you looked straight at it, you鈥檇 never see it.鈥�
Another observer, Kevin Mace, says 鈥淚t looked like a faint star. It鈥檚 not visually stunning.鈥�
That should be no surprise considering Xena鈥檚 distance and the fact that it is about 5 million times dimmer than Polaris, the North Star. The observatory says Xena is right at the limit of what the un-aided human eye can see using the Struve scope.
Although their view of Xena may not have been aesthetically inspiring, the astronomers spent weeks preparing, reviewing images and carefully charting Xena鈥檚 orbit. The McDonald Observatory鈥檚 Frank Cianciolo applauded the group for what he called 鈥渆xtreme astronomy鈥�.
鈥淚t is a testament to the incredible skill and dedication some amateurs show to their passion for astronomy that the folks on the dome floor that night are, to anyone鈥檚 knowledge, the only humans on the planet to have seen UB313 through an eye-piece,鈥� Cianciolo says.
