The nebula has no single designation but is covered by NGC 2237, NGC 2238, NGC 2239 and NGC 2246,
with the central star cluster NGC2244.
Description
The massive young stars in the central cluster formed
perhaps a million or so years ago.
Their intense light causes the surrounding gas to
glow, and combined with their stellar winds has carved out the hollow
central portion of the nebula. This process will continue over the next
few million years until the whole nebula has been dissipated.
The image covers an area of sky equivalent to the width of around three full moons.
Prime focus test image. Taken after system optical tilt diagnosed to be due to non-orthogonal
CCD mounting, and fixed with shims made from slices from a can of 7-UP.
Collimation still to be completely dialed-in.
No guidescope yet connected. Short exposures used to reduce trailing.
Threw away worst 50% of results. Remaining star trailing fixed with Focus Magic motion blur removal.
Dithered. CCD setpoint 0C to avoid CCD window condensation issues (prior to heater fix).
