Owl Nebula (M97)

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About this Image

The faint Owl Nebula M97 is one of the more complex planetary nebulae. Its appearance has been interpreted as that of a cylindrical torus shell (or globe without poles), viewed oblique, so that the projected matter-poor ends of the cylinder correspond to the owl's eyes. This shell is enveloped by a fainter nebula of lower ionization and a very faint O-III envelope, just visible in this image.
The mass of the nebula has been estimated to amount 0.15 solar masses, while the 16 mag central star is believed to be of about 0.7 solar masses. Its dynamical age is about 6,000 years. Its distance is some few thousand light years.
In the background around this nebula there are many faint and distant background galaxies, the brightest one to the right of M97, mag 16 PGC34279. North is to the bottom left.


Technical Details


16" cassegrain in corrected secondary focus at f/10

Mount ASA DDM-85XL
Camera SBIG STX16803 at -30C, STX filter wheel
Filters Baader LRGB-Ha-OIII
Date March 2011.
Location Wildon/Austria
Sky Conditions mag 5-5.5 sky, raw FWHM 1.6-2.2", temperature 5-10 C
Exposure L:R:G:B = 600:60:60:80 minutes (20-minute sub-exposures),
Ha:O3 = 240:180 minutes (30-minute sub-exposures)
Programs used Maxim DL 5;
Photoshop CS5
North is to the bottom right side;