Thực đơn
NGC_491Thực đơn
NGC_491Liên quan
NGC 491 NGC 4993 NGC 499 NGC 495 NGC 4138 NGC 4111 NGC 496 NGC 4319 NGC 4151 NGC 498Tài liệu tham khảo
WikiPedia: NGC_491 http://cseligman.com/text/atlas/ngc4a.htm#480 http://ned.ipac.caltech.edu/cgi-bin/objsearch?objn... https://dso-browser.com/deep-sky/1380/ngc-491/gala...