M7, Ptolemy's Cluster, in
A map of the star field. Magnitudes are given without
a decimal point, e.g. 67 is to be interpreted as magnitude 6.7.
A glorious highlight of the summer sky through binoculars. Very bright, and easily seen even from urban areas. A rich central area containing a prominent cross shape is surrounded by a looser sprinkling of stars in a witch's hat configuration.
60-degree field of view
Data (Janes, Duke, and Lynga, 1987) RA 17 54 dec -34 49 total V magnitude 3.3 NGC number 6475 Trumpler class I 3 r angular diameter 80' distance 240 pc age (Myr) 130 integrated B-V .15 observed stars 54 earliest sp. class B8 brightest star 7.0
(c) Copyright 1998 Benjamin Crowell. All right reserved.
Photos from the Digitized Sky Survey, stdatu.stsci.edu/dss/dss_form.html
Sky maps created by Your Sky, www.fourmilab.com