[PAR] [TLE] 101 Helena [SEP] 101 Helena is a rocky main-belt asteroid.  It was discovered by Canadian-American astronomer J. C. Watson on August 15, 1868, and was named after Helen of Troy in Greek mythology.  Radar observations were made of this object on Oct 7 and 19, 2001 from the Arecibo Observatory.  Analysis of the data gave an estimated ellipsoidal diameter of 71×63×63 ± 16% km.  The diameter estimated from IRAS infrared measurements is 66 km.  It is classified as an S-type asteroid in the Tholen system. [PAR] [TLE] Arecibo Observatory [SEP] The Arecibo Observatory is a radio telescope in the municipality of Arecibo, Puerto Rico.  This observatory is operated by SRI International, USRA and UMET, under cooperative agreement with the National Science Foundation (NSF).  The observatory is the sole facility of the National Astronomy and Ionosphere Center (NAIC), which refers to the observatory, and the staff that operates it.  From its construction in the 1960s until 2011, the observatory was managed by Cornell University.
[PAR] [TLE] 101 Helena [ SEP ] 101 Helena is a rocky main - belt asteroid . It was discovered by Canadian - American astronomer J. C. Watson on August 15 , 1868 , and was named after Helen of Troy in Greek mythology . Radar observations were made of this object on Oct 7 and 19 , 2001 from the Arecibo Observatory . Analysis of the data gave an estimated ellipsoidal diameter of 71×63×63 ± 16 % km . The diameter estimated from IRAS infrared measurements is 66 km . It is classified as an S - type asteroid in the Tholen system . [PAR] [TLE] Arecibo Observatory [ SEP ] The Arecibo Observatory is a radio telescope in the municipality of Arecibo , Puerto Rico . This observatory is operated by SRI International , USRA and UMET , under cooperative agreement with the National Science Foundation ( NSF ) . The observatory is the sole facility of the National Astronomy and Ionosphere Center ( NAIC ) , which refers to the observatory , and the staff that operates it . From its construction in the 1960s until 2011 , the observatory was managed by Cornell University .
Radar observations of 101 Helena were made from the Arecibo Observatory in what year?
Radar observations of 101 Helena were made from the Arecibo Observatory in what year ?
2001
2001