Waterfall and Chevron Nebula Region
and Reflection Nebulas in Orion
Instrument: 12.5" f/5 Home made Newtonian
Platform: Astrophysics 1200 QMD
CCD Camera: SBIG 10XME NABG with Enhanced Water Cooling
Guider: SBIG ST4
Exposure: (Ha+R)GB = 120+20:20:20
RGB Combine Ratio: 1: 1.05: 1.11
Filters: AstroDon RGB Tricolor
Location: Payson, Arizona
Elevation: 5150 ft.
Sky: Seeing FWHM = 10 arcsec (Maxim DL - 10min subframe), Transparency 9/10
Outside Temperature: 35 F
CCD Temperature: -30 C
Processing Tools: Maxim DL, Gralaks Sigma, Photoshop, PixInsight, CCDOps Debloomer.
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was specifically selected to include both the two primary nebulosities
- HH222 and HH401 in center, the small patch to the upper right
- HH33 & HH40, and finally a surprising unidentified reflection
nebula on the left. At top center is Herbig Haro 222, known from
a research paper as the "Waterfall Nebula". I brought
this unique object to the spot light a few years ago, when I
posted a color image of it with my ST7E. Now I'd like to introduce
to you another heavily researched object just below it, known
from the same research paper as the "Chevron Nebula".
This object is Herbig Haro 401 and is also a jet of gas streaming
out of a cocoon surrounding an enclosed young star. Both nebulas
are extremely faint, and require deep images to show their nature
well. At the top are two more Herbig Haro objects, HH33 and HH40
connected by a nebulous bridge of material.
On the left
edge is a very mysterious object. I first recorded it in a quick
1 minute exposure the night before, seconds before being clouded
out. Later that night, I discovered this strange combination
of dust and reflection nebulosity and I knew I had to include
it in the composition. The deeper exposure above shows it to
be white to greenish in color, a combination of blue reflection
nebulosity and yellow dust.
A standard series of unbinned RGB frames were taken, and followed
by 2h of an Ha filtered series. The RGB data was combined normally
for a standard G2V calibrated image. The Ha data was combined
to make a high resolution deep frame. The R channel was extracted
from the RGB, combined with the Ha data at 80% Ha - 20% Red.
This was then combined again with the R channel using lighten
to return the stars to the red channel. Finally, this was the
new R channel and recombined with the G and B data for a RGB
color image. This technique avoids white clipping the R channel,
and allows the full blue nebulosity to be present in the image.