2244 - THE
ROSETTE NEBULA in "CFHT" COLORS
Red = Ha, Green
= OIII, Blue = SII
2 frame MOSAIC
is an attempt to take spectral line emission data as
the HST mapped shot (see <here>)
and rearrange the color channels in a technique made
known by the Canada-France-Hawail Telescope, or CFHT.
Whereas the Hubble "maps" the same data set
with Sulfur as Red, Hydrogen as Green, and Oxygen as
Blue, the CFHT mapping simply switches the channels
Therefore, in the image above,
reddish areas represent Hydrogen gases, greenish areas
are Oxygen, and bluish areas are bluish. Of course
when you mix gases in the same area, the colors also
mix to form a distinct "palette" of colors.
For NGC 2244
mapped to "Hubble" colors, click <here>
NGC 2244 in regular RGB, click <here>
Observatory near Azle, Texas and Date: November,
2005 to January 2006
Scope/Mount: 12.5" RCOS
RC and Paramount ME
Camera: SBIG STL-6303e astro
Filters: Custom Scientific 4.5nm Ha,
OIII, and SII spectral line filters.
Exposure Info: Mapped
color mosaic - Ha/OIII/SII - 210:60:90 minutes for left side and
150:90:90 minutes for right side (20 and 30 minute subexposures
Registration, and DDP in CCDStack. Color mapping, cropping, color balance, levels/curves, sharpening, and
noise removal (Astronomy Tools/Pro Digital Software) in Photoshop CS.
The SII data is mapped
to the red channel, Ha to green, and OIII to blue. Seeing
was exceptional for the left side of the mosaic, but poor for the
right. Interesting to note that despite similar conditions,
the left side is much cleaner than the right side despite having
less exposure time in Ha.
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