Plot Sun's RA vs Dec in MS Excel

[Astroegg]

I want to demonstrate the equatorial coordinates of the Sun in an excel chart (plotting Right Ascension against Declination) as a nice type of sine curve, and show the points on the curve where the equinoxes are and the solstices. Can anybody please tell me what equation I should use to get the data into a nice curve?

Data...

Vernal Equinox: 0h 00m, 23.4˚

Summer Solstice: 6h 00m, 0.0˚

Autumnal Equinox: 12h 00m, -23.4˚

Winter Solstice: 18h 00m, 0.0˚

Vernal Equinox: 24h 00m, 23.4˚

[Astroegg]

A suitable example graph: Positional Astronomy: Ecliptic coordinates