C6 — Cat's Eye Nebula

About

A planetary nebula in Draco: the shell of gas shed by a dying star, roughly 3,300 light-years away. Hubble images show knots, jets and faint concentric rings around the bright centre, and the bright part is thought to be about 1,000 years old.

Imaging tips

• The bright core is only about 20 arcseconds across, so it is too small to frame: use a long focal length and a fine pixel scale.
• The core is very bright and the surrounding shell is very dim, so expect to blend a short-exposure core with deep data for the halo.
• One image of the shell used close to 24 hours, mostly Hα and OIII, since the halo spans some fifteen times the width of the core.
• In a wider field, NGC 6552 (a barred spiral, about 350 million light-years off) is the most prominent galaxy.
• Best around June and July; it peaks near 73° altitude from 50°N.