3 minutes exposure, Meade 416XT CCD.
5" f/5 refractor at prime focus.
Gum 25 is a fairly small emission nebula in Vela, surrounding a short chain of 10th and 11th magnitude stars. I is situated about 1.5 degrees south of Gum 23. It is relatively bright and quite easy to observe with an 8" telescope under dark skies.
In this image, the stars seem bloated due to the usual problem of unfiltered CCD imaging with a short-focus achromatic refractor. Chromatic aberation causes the infra-red light to focus significantly differently from blue and green light, causing the stars to bloat.
Colin gum was an Australian astronomer in the 1950's who made extensive photographic studies of the southern Milky Way. As a result of his research he published a catalogue of southern emission nebulae he discovered. The most famous object in his catalogue is Gum 12, the Vela supernova remnent, usually just refered to as "The Gum Nebula".
