The earliest recorded supernova.

[glenc]

RCW 86: Historical Supernova Remnant


(http://chandra.harvard.edu/) Explanation: In 185 AD, Chinese astronomers (http://en.wikipedia.org/wiki/Chinese_astronomy) recorded the appearance of a new star in the Nanmen asterism - a part of the sky identified with Alpha and Beta Centauri on modern star charts. The new star (http://www.tass-survey.org/richmond/answers/historical.html) was visible for months and is thought to be the earliest recorded supernova. (http://arxiv.org/abs/astro-ph/0301603)
See APOD today.
http://antwrp.gsfc.nasa.gov/apod/image/0609/rcw86_xmmchandra_f.jpg

The Chinese noted that it sparkled like a star and did not appear to move in the sky, arguing against it being a comet. Also, the observers noticed that the star took about eight months to fade, consistent with modern observations of supernovas.
http://www.universetoday.com/2006/09/18/the-location-of-the-oldest-recorded-supernova-discovered/

See also:
http://galaxymap.org/cgi-bin/details.py?id=27176&t=hii&s=4_p21.0xp42.0&name=RCW%2086
and
http://archive.eso.org/dss/dss/gif?/tmp/.www/dss/dss4167a1t0.gif

RCW 86 is 1.8 degrees south of Alpha Centauri. (pa 177d)
RA2000 14h 40.5m, dec –62d 40m, size 3’ x 3’

[bojan]

How they managed to see Alpha Cen from China? Perhaps only from southern parts... it must have been very low, just above the horizon....
Possibly precession also helped a bit here, I will check with CdC..

[SMR]

Hi Bojan,

Shouldn't be a problem for them. Modern Hong Kong is around 22N latitude, so Centaurus gets above the horizon there, though not by much. The border with modern Vietnam is around 21N, and Hainan gets you to 18N. Take away the modern light and air pollution, and I reckon it's doable.

Steve.

[glenc]

More information is at:
http://www.blackskies.org/nsp16.htm

The SN was first seen from Lo Yang (112 26E, 34 40N) on 7/12/185.
Precession means it was higher above the horizon then.

Andrew James writes.

Reports and observations in the historical record come from a provincial city known as Lo Yang. (Latitude +34.7dN) Invisible from this location today, precession places this "new star" at declination -51d36' S (185AD) whose southerly culmination is some 3.6d above the horizon.

It was seen for 8 or maybe 20 months. http://arxiv.org/abs/astro-ph/0301603

[mattweather]

Yeah i seen it before, good article anyway:) It nice if you see a supernova because you'ill see nice colours and structures in the sky esp at night. I know it kinda dangerous if they affect us.

[Checker]

Thats really interesting. I read somewhere that it was in Thailand that the first supernova was seen. Oh well, learn something new everyday.

[glenc]

Part of RCW 86 should be visible with an amateur scope and UHC filter.
This image is from galaxymap.org
The pink part at lower right is 1.8 degrees from alpha Cen in pa 177 degrees.
The bright blue star at top left is BT Cir.

[GrahamL]

was this the one we looked for the other night glen ?

[glenc]

yes, must try again when it is higher.