TY  - GEN
AU  - Gregersen, Erik 
TI  - Astronomical observations: astronomy and the study of deep space 
SN  - 9781615300259
U1  - CH520 
PY  - 2010///
CY  - New York
PB  - Britannica Educational Publishing, 
KW  - Astronomy : Observation
KW  - Astronomical : Instruments
ER  -