This project shows the meaning of the star within the crescent on Roman coins is likely symbolic for a solar eclipse. The star is a planet to the ancients and the crescent is the sun. The ram is an astrologic symbol for ancient Judea or the lands from Antioch to Egypt.

Please see the below link to, " The Evidence for Aries the Ram as the Astrological Sign of Judea, " by Michael R. Molnar

Clearly one sees a planetary body moving over the sun in this photo. This is the Antioch ram coin issued from Nero in 55-56 AD. From the T. Cartwright collection

Eclipse diagrams are taken from the NASA Website, "Canon of Solar Eclipses"

Acknowlegements, Eclipse Predictions by Fred Espenak, NASA/GSFC

Thanks to the Vcoins search engine website and the individual vendors for the photos as cited