2 minutes exposure. Meade 416xt CCD.
5" f/5 refractor at prime focus.
The Keyhole Nebula (also sometimes called the Eta Carina Nebula) is the brightest emission nebulae in the sky. It is easily visible to the naked eye as a cloudy patch in the Milky Way, not far from the Southern Cross. The Keyhole nebula is definitely one of the top 5 objects of the southern skies. Even in binoculars, the field is strewn with patches of light and dark nebulosity. In a telescope the view is magnificent. Situated in the heart of one of the richest portions of the Milky Way outside of Sagittarius, the entire region abounds in clusters and double stars. Interestingly however, there are few emission nebulae. It is as though all of the nebulae in the region had been gathered up together to make one stupendous object!
Adding a 10 minute exposure to the first image allows for more of the nebulosity to be visible. Unfortunately, such a long exposure results in many of the brighter stars blooming considerably. The star with the longest bloom streak is the 5th magnitude hypermassive star eta carinae. About 150 years ago this star was the second brightest star in the sky as it underwent a nova-like outburst that lasted many years. A 10" telescope will reveal the tiny nebula surrounding this star, called the Homuclus, which is material that has been ejected by the star.
