Solar and Lunar Almanac for central Maryland

What are the Solar and Lunar Almanacs?

The Solar and Lunar Almanacs give Solar and Lunar rise and set times, transit times, and twilight times. They also give the semidiameter of the sun and moon. Each time is called an event and is designated by a three letter code as given below. 
                EVENT KEY
SLT: Sun Lower Transit           SUT: Sun Upper Transit
SRS: Sun Rise                    SST: Sun Set
                     Twilights:
SMC: Sun Morning Civil           SEC: Sun Evening Civil
SMN: Sun Morning Nautical        SEN: Sun Evening Nautical
SMA: Sun Morning Astronomical    SEA: Sun Evening Astronomical

MLT: Moon Lower Transit          MUT: Moon Upper Transit
MRS: Moon Rise                   MST: Moon Set

SD = Object semidiameter in arc minutes.

The Solar and Lunar events are listed in the order of occurrence so are mixed together.

How good are the listed times?

Under ideal conditions times should be good to better than a minute. This assumes standard temperature and pressure at sea level. It also assumes that the true horizon is visible. Usually one or more of these conditions does not hold exactly so times will differ from those listed somewhat. Atmospheric variations can cause several minutes of time difference.

A major source of time error is a difference in the observer location from the reference location.

Where are the listed times valid?

Reference Location: 77 degrees West Longitude
                 39 degrees North Latitude
  This is in Silver Spring, MD.  This location gives
  even coordinates and is fairly central.

For ideal conditions times are accurate to better than one minute but not as good as a second. I would guess the accuracy is around 20 seconds. Times are given to seconds to allow better correction to another location. It is easy to correct times to another location in the area.

Almanacs by month

Be careful of time zones used. One time zone is used for each entire month even though times may change within a month. The time zone is either EST (Eastern Standard Time, 5 hours behind GMT) or EDT (Eastern Daylight Time, 4 hours behind GMT).