IC 1747 is a very interesting PN even with some difficulties of visual observation. In 8" telescopes it shows a vague anular shape at high magnifications, in which brightness lacks of homogeneity. Infact, a bright arch is visible toward N direction, and a deeper observation could reveal another condensation opposite to the first (toward S). Central star hardly emerges among gases of this nebula.
Astronomical researches haven't been continuous during past years, and it has not been possible yet to resolve some doubts on its morphology: studies carried on in '80s show a bipolar-toroid structure, with its polar axis toward us, so that we can observe its ring coinciding the equatorial toroid.
Recent studies underlined the presence of a faint asymmetrical halo, outside the main nebula, noticeable only with long exposure Halpha survey.
Interesting level: **** |
