View Full Version : Pre-telescopic Sun: what had been discovered?

2011-Apr-28, 02:25 PM
That the Sun was round, and so very likely a sphere (heliocentrism required?).

That it had, sometimes, sunspots.

The existence of the corona.

That its light was constant, both in intensity and colour (heliocentrism required?).

How well was its size (radius) known, before 1609?

Had prominences been reliably observed (and recorded!), during total eclipses, before Galileo?

In Galileo's day, the following were discovered:
~1620: faculae (I'm not sure of this)
1630: solar rotation (Scheiner)

Post-Galileo discoveries (to 19th century):

1748: limb darkening (Bouguer)

1700s? chromosphere

1800-1802: granulation (Herschel), infrared emission (also Herschel), ultraviolet emission (Ritter), absorption lines (Wollaston; Fraunhofer independently discovered them in 1814)

1843: solar cycle (Schwabe)

1859: solar flares (Carrington)

Plages, filaments, super-granulation: ??

Edits and additions welcome! :)

2011-Apr-28, 02:40 PM
I believe sun spots where known over 2,000 years ago by Chinese astronomers. They were very good with both observations and recording and preserving the data. They have records of solar prominences from about 1400 BC

2011-Apr-29, 08:15 PM
As late as 1939 to 1942, Hoyle and Lyttleton thought that the Sun's constant energy output was fueled simply by the Sun's travels through the galaxy, accreting gas as it went. - ref: Simon Mitton (2005) Conflict in the Cosmos, Fred Hoyle's Life in Science