How to Read the Time zone Image
Here you can find some information about how to read the time zone image on which you have clicked.
The Clock
The clock shows Universal Time (UT) for the time and date setting which was entered for the chosen city. If UT does not fall on the same day, the date is shown as well. Morning hours (AM) are shown in red and afternoon hours (PM) in blue.
The Map
The image on which you clicked shows a world map of all the atlas places contained in our atlas database. The red crosshairs meet at the exact location of the place you have selected. The red lines are labelled with latitude and longitude respectively. Places which are in the same time zone as your selected place are highlighted in the green area which is labelled at the top of the map.
and The Bubble
Near the selected location a yellow bubble is shown which holds two lines of additional information: the offset from Universal Time and the time type. 
This is an example for locations which are one hour east of Greenwich,
i.e. one hour later than Universal Time. The abbreviation 'Std.'
denotes that we have Standard Time as opposed to Daylight Savings
Time which is abbreviated as 'DST'.
A bubble similar to the one shown on the right is used for dates prior to the
introduction of time zones. It shows the Local Mean Time offset (LMT)
of a meridian which is 21 degrees and 15 minutes of arc to the east of the meridian
through Greenwich, i.e. we have (dividing by 15) one hour and 25 minutes later
than Universal Time here.
Special dates
To enter a date in the years 0001 to 0099 AD, you must prefix the year with two zeroes. Any year number between 1 and 99 will otherwise be transposed into the current epoch.Years before 1 AD must be entered in astronomical year style as negative numbers. The astronomical year -1 corresponds to the historical year 2 BC. The difference arises from the fact that the astronomical year numbering has a year zero, while in the historical year numbering 1 BC is followed by 1 AD.