M101 Spiral

Enhanced Hydrogen Comparison

Uploaded 6/11/07

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Select an image size for a larger view: 1024 x 768 1600 x 1200

Riding high on May evenings is this stunning face on spiral, sometimes called the "Pinwheel Galaxy" in Ursa Major. The small yellow core, and thick blue arms wrapping around the core studded with a large collection of HII regions, Blue stellar associations and dark nebula set this amazing object off as one of the most beautiful spirals in the sky. A whopping 30 arcminutes in size, it pours over the edges of my field of view with faint wreath like tendrils of nebulosity. At a bright magnitude 8.3, it is a low surface brightness object visually spread over half a degree of sky, however photographically it is a skyshooters delight. Classed as an SAB(rs)cd spiral, its inclination is less than 1 degree and is face on to our line of sight. The B-V index indicates an overall neutral hue, which integrates the yellow core regions with the outer blue but fainter arms. The "average" color of this galaxy is quite neutral.

Hordes of faint background galaxies dot this image, most being a leaden yellow color, dimmed from their great distance through intergalactic dust.

The brightest knot in the arms to the upper right of the nuclear region is NGC5462, an complex blue stellar association with a rim of red hydrogen around its energetic core. When we add the hydrogen data to the image, we get the image on the right. The galaxy dynamics that become visible here simply boggles the mind as we can now easily see the complex interaction between hot OB associations and the surrounding ionized hydrogen. It can also be seen that there are numerous small isolated hydrogen patches in and around this large and close spiral, and in most cases a small blue star or cluster can be seen within or nearby.

Instrument: 12.5" f/5 Home made Newtonian Mount: Astrophysics 1200 QMD CCD Camera: SBIG 10XME NABG with Enhanced Water Cooling Guider: Meade DSI-C w/Lumicon Newt Easy Guider Exposure: L= 4h. RGB = 40:40:40, Ha = 3h Location: Payson, Arizona, Elevation: 5150 ft. Sky: Seeing FWHM = 4.2 arcsec (Maxim DL - 10min subframe), Transparency 9/10 Outside Temperature: 55 F CCD Temperature: -30 C Image Processing Tools: Maxim DL: Calibration, deblooming (Starizona Debloomer), aligning, stacking Gralaks Sigma: Stacking PixInsight: Curves, Deconvolution, noise reduction Photoshop CS2: Curves, Color Correction, Gradient removal (Grad Xterminator), Cleanup HOME GALAXIES EMISSION NEBS REFLECTION NEBS COMETS GLOBULARS OPEN CLUST PLANETARIES LINKS


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