Donuel, you did indeed see two tails on that comet. I photographed the same comet, Hale-Bopp; and the dual tail shows clearly. The two tails thing is not at all uncommon in the world of uncommon comets. The brighter white or white-green tail is composed of out-gassing vapors and dust particles spiraling out pushed by the solar wind. The blue tail is ionized hydrogen plama. The mass of the ionized gas is very low. The gas is blown in a line directly out from Sun by the pressure of light. So it's the difference between the masses of the dust and the ionized gas that makes a difference in angle possible. Both tails are always present in active comets within the inner solar system (roughly inside the orbit of Jupiter). The angle between the observer's position on Earth and the orbital path of the comet determine whether or not you will see ion tails. It's not unusual for them to be hidden behind the much brighter dust tail. Also the dimmer ion tail will tend to be hidden by the level of light pollution that you have in Rockville. Hale-Bopp just happed to be an exceptionally bright comet; so its ion tail was proportionally brighter.