Hubble Space Telescope image of Terzan 1, a globular cluster that lies about 22,000 light-years from Earth in the constellation Scorpius. Credit: ESA/Hubble & & NASA, R. Cohen
Terzan 1 is a globular cluster situated around 22,000 light-years away from Earth in the constellation Scorpius. It is one of 11 globular clusters that were found by the Turkish-Armenian astronomer Agop Terzan in between 1966 and 1971. This is a period when he was working in France, based mostly at Lyon Observatory.
Rather confusingly, the 11 Terzan globular clusters are numbered from Terzan 1 to Terzan 12. He did not make it clear that Terzan 5 and Terzan 11 were one and the very same, although another astronomer, Ivan Robert King, did publish a note to try and clear up the confusion. These days, most papers recognize the initial Terzan 5 and Terzan 12, and accept the curiosity that there is no Terzan 11.
Hubble Space Telescope picture of Terzan 1 caught by the Wide Field Planetary Camera 2. Credit: NASA & & ESA, Acknowledgment: Judy Schmidt (Geckzilla).
Terzan 1 is not a brand-new target for Hubble– a picture of the cluster was released back in 2015 (see image above), taken by Hubbles Wide Field Planetary Camera 2 (WFPC2). That instrument was replaced by the Wide Field Camera 3 (WFC3) throughout the 2009 Hubble servicing mission. WFC3 has both remarkable solving power and a wider field of view than WFPC2, and the enhancement is obvious in this exceptionally detailed image.
By ESA/Hubble
October 9, 2022
Somewhat confusingly, the 11 Terzan globular clusters are numbered from Terzan 1 to Terzan 12. He did not make it clear that Terzan 5 and Terzan 11 were one and the exact same, although another astronomer, Ivan Robert King, did release a note to attempt and clear up the confusion. These days, most documents recognize the original Terzan 5 and Terzan 12, and accept the quirk that there is no Terzan 11.