h alpha filter

flickr

Bubble Nebula - June 15, 2016 by Joseph Brimacombe
Via Flickr:
Taken from New Mexico Skies with an SBIG STL-11000 camera and 51-cm RCOS telescope on a Software Bisque PME II mount. Red and H-alpha filters were used and the data blended to form the final image.

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Jones 1, PK 104-29.1 by hauk sven
Via Flickr:
PK 104-29.1, also known as “Jones 1”, is a very faint, ghostlike planetary nebula in the constellation of Pegasus. This image was taken at the Mayall telescope with the Mosaic camera, with [OIII] (assigned a blue color) and H-alpha (orange) filters. In the image North is up and East is to the left. Imaged August 28, 2009.