NGC7293, known as the Helix nebula, with an apparent diameter of 15' (half of the full moon), is the most extended planetary nebula visible. However, getting good images of it is not so easy, due to the extremely low surface brightness. An amazing image of the Helix was got from HST, but much of the details can be revealed (of course with a lower resolution) also with small scopes and all of the most recent CCD cameras, with very long exposures and the use of Ha filters. The Helix distance from earth is estimated to be about 400 l.y., very close to us.
- Camera : Starlight Xpress SXV-H9 with Astronomik 13nm Ha dichroic filter
- Telescope : Takahashi FS-102 at F/8 on a GM2000-FS2
- Guiding : ST4 on a Vixen 80/910mm.
- Exposure : 6x1200sec. unbinned
- Processing : MaxIm (align, combine, stretching) - Photoshop (final enhancing)
- Location : St. Barthelemy (Val d'Aosta) - 1800 mt. height
- Date : September 18, 2004
Click here to see a higher resolution image