NGC 2237 - The Rosette Nebula in Hydrogen-Alpha light


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Copyright 2009 Hap Griffin

The Rosette Nebula, NGC 2237, certainly lives up to its name.  A glowing cloud of hydrogen 130 light-years across, it is the birthplace of the loose star cluster in its interior (NGC 2244).  This nebula is huge...although 5200 light-years distant, it spans roughly a degree of sky, or twice the diameter of the full moon.  The central star cluster is visible to the naked eye, but the nebula itself is tough to see even in a telescope without a special optical filter such as a Lumicon UHC.  The stars in the central cluster were formed out of the gas and dust in the nebula's center, resulting in its thinness there.

The dark, stringy objects scattered through the nebula are known as Bok Globules, named after Bart Bok, the astronomer who studied them extensively.  They are regions of compressed gas and dust in the first stages of star formation.

This image was captured through a narrowband filter admitting only a narrow slice of spectrum around the wavelength of glowing hydrogen.  Thus it is a monochrome (single color) image displayed as shades of grey.


Date/Location:    November 8, 2009     Griffin/Hunter Observatory    Bethune, SC
Camera: QSI 583wsg
Filters: Astrodon E Series Generation 2 HA (5nm BW)
CCD Temperature: -20 C
Instrument:    Takahashi FSQ-106N 
Focal Ratio:   f/5
Mount: AP-1200
Guiding:    Auto through Orion 10" Newtonian w/ SBIG ST-402
Conditions:    Clear and dry
Weather:    40 to 32 F, still
Exposure: 230 minutes total (23 x 20 min)
Capture: CCDAutopilot w/ Maxim DL Camera Control, focused automatically w/ FocusMax and Robofocus.  
Processing:    Frame calibrations, alignment, initial DDP with ImagesPlus v3.80.  Finishing in Photoshop CS4.