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Click the image for a larger view.
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Instrument |
Takahashi FSQ-106ED @
f/5.0 (530 mm F.L.) Captured at 2.1 arcsec/pixel. Shown at
4.2 and 10.66 arcsec/pixel. |
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Mount |
Losmandy G11 with Gemini L4 v1.0 |
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Camera |
SBIG STF-8300M Self
Guiding Package w/ mono ST-i, using Baader LRGB filters. |
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Acquisition Data |
2/5/2013
to 11/9/2013 Chino Valley, AZ... with CCDAutoPilot5 & CCDSoft. |
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Exposure |
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Lum |
525
min. (35 x 15 min. bin 1x1) |
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Red |
120 min. (8 x
15 min. each bin 1x1) |
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Green
|
135 min. (9 x 15 min. each bin 1x1)
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Blue
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165 min. (11 x 15 min. each bin 1x1)
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Software & Processing Notes |
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CCDSoft, CCDStack,
Photoshop CS6, PixInsight and Noel Carboni's actions.
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eXcalibrator v4.2
for (g:r) color balancing, using 59 stars from the SDSS-DR9
database.
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CCDStack to
calibrate, register, normalize, data reject, combine the sub
exposures and to create the RGB and luminance image.
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PixInsight for
color gradient removal, and initial non-linear stretching.
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PhotoShop for the
LRGB combine & final touch-up.
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Noiseware 5, a
PhotoShop plug-in.
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Comment |
The nebula is shown
rotated 180°, with North to the bottom.
IC 2118, also known as
the Witch Head Nebula, is a faint reflection nebula in the
constellation Eridanus, at a distance of about 900 light-years from
Earth. The nearby bright star Rigel illuminates the nebula. Although
Rigel is a blue star, IC 2118 gets much of its blue color because
the gas and dust scatter blue light more so than red. This same
effect makes our sky appear blue.
Observations, at radio
wavelengths, show areas of carbon monoxide emission throughout parts
of IC 2118. This indicates the presence of molecular clouds and star
formation within the nebula.
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