IC 4756 is a large bright open cluster in the constellation Serpens. Known as Graff's Cluster, it is bright enough to be seen with the naked eye and considered a fine cluster for binoculars or small telescopes.[2]
IC 4756 is also known as the Tweedledee Cluster (paired with NGC 6633 as Tweedledum), also as the Secret Garden Cluster.[3]
Metallicity of IC 4756 is similar to the Sun, at -0.02±0.01 dex.[4]
Open star clusters IC 4756 (left) and NGC 6633. Original astrophoto.
^ abc"IC 4756". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 30 November 2016.
^Michael Bakich. "The Omega Nebula, Graff's Cluster, and planetary nebula IC 1295". astronomy.com. Retrieved 2020-10-05.
^O'Meara, Stephen James (2007). Deep-Sky Companions: Hidden Treasures. Cambridge University Press. p. 457-458. ISBN 978-0521-83704-0.
^Bagdonas, Vilius; Drazdauskas, Arnas; Tautvaišienė, Gražina; Smiljanic, Rodolfo; Chorniy, Yuriy (2018), "Chemical composition of giant stars in the open cluster IC 4756", Astronomy & Astrophysics, 615: A165, arXiv:1804.01975, Bibcode:2018A&A...615A.165B, doi:10.1051/0004-6361/201832695, S2CID 118857628
IC4756 is a large bright open cluster in the constellation Serpens. Known as Graff's Cluster, it is bright enough to be seen with the naked eye and considered...
post-blue straggler in the open cluster IC4756 that contains a large excess of lithium. HD 172189, also located in IC4756, is an Algol variable eclipsing binary...
Evolution in Five Intermediate-age Clusters: NGC 2360, 2423, 5822, 6811, and IC4756". Astronomy and Astrophysics. 273 (1): 61–72. Bibcode:1990A&A...237...61M...
telescopes. NGC 6633 is also known as the Tweedledum Cluster (paired with IC4756 as Tweedledee), also as the Captain Hook Cluster. It is also designated...
IC 2431 are a group of interacting galaxies in the constellation of Cancer. They are located 684 million light-years away from the Solar System and were...
Evolution in Five Intermediate-age Clusters: NGC 2360, 2423, 5822, 6811, and IC4756" (PDF). Astronomy and Astrophysics. 273 (1): 61–72. Bibcode:1990A&A...237...
2007). "Na, Al, and O Abundances of Open Clusters NGC 7142, NGC 6939, and IC4756". The Astronomical Journal. 134 (3): 1216–1230. Bibcode:2007AJ....134.1216J...
Global Information
