Duplicate Signals at the Baltimore Observatory
circa 1818-1819
circa 1818-1819
circa 1856-1860
1887
circa 1931
circa 1805-1860
circa 1867
undated
undated
undated
1863
1863-06-15
circa 1830
circa 1880s
undated
1750
undated
1775-1800
circa 1850-1860
1835
1865
1910-09-18
1792
20th century
1820
circa 1915-1920
circa mid-19th century
circa 1866
1992-1993
1863
1815-1849
circa 1851
circa 1860
1950
circa 1900
1904-06-14
circa 1890
1889-11
1882
circa 1860
circa 1880
undated
circa 1915
circa 1915
circa 1895
circa 1895
1919
circa 1900
circa 1948
1950-12
circa 1850
circa 1800
1955
1804
circa 1881-1882
1936
1792
20th century
circa 1853-1856
1846
1839