Daily Image

Click here or on the picture for a full size image.

Colours in the summer sky

Submitter: Albert van Duin
Description: M27, the Dumbbell nebula, was discovered in 1764 by Charles Messier. It is a so called planetary nebula, which has nothing to do with planets, but in the telescopes of those days they resembled faint planetary disks. What we actually see is star (in the center) that has been shedding shells of gas. This is one of the brightest and most colourful nebulae in the northern sky.

Visually, through a telescope, it looks greyish because the colours are so faint. But when we make a photograph the bright shades of red and green show. Red colours are caused by ionized Hydrogen (H-Alpha) and green by ionized Oxygen (OIII), the UV-light of the central star is causing the ionisation. This image is a combination of only three a CCD exposures of 5 minutes each through RGB filters. The telescope used is a homemade 40cm f/4 Newtonian.
Copyright: Albert van Duin
  Follow us on Twitter
Please feel free to submit an image using the Submit page.