Celestial hemisphere:  Southern  ·  Constellation: Aquarius (Aqr)  ·  Contains:  Helix Nebula  ·  NGC 7293
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NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”), Mark Wetzel
NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”)
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NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”)

Getting plate-solving status, please wait...
NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”), Mark Wetzel
NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”)
Powered byPixInsight

NGC 7293, The Helix Planetary Nebula in Aquarius (“The Eye of God”)

Equipment

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Acquisition details

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Description

Casitas de Gila, Gila, NM, Oct 16 – 20, 2020

Reprocessed 02/21/2023

Original Version:

I went to Casitas de Gila, Gila, New Mexico in October for astrophotography under clear, dark skies.  I was there for 12 days and there were a few nights of excellent transparency and seeing.  However, high altitude smoke from the California wildfires made imaging a challenge for a few nights.  The first deep sky object that I imaged was the Helix Nebula in the constellation Aquarius.  This planetary nebula was captured with two narrowband filters, Hydrogen-alpha (Ha) and Oxygen-III (OIII) over three nights.  This is a false color image that combines Ha in the red channel, and Ha and OIII in the green channel and OIII in the blue channel.  The white dwarf can be seen in the center of the pupil of the eye.  This image also reveals the outer “eyebrow” of expanding hydrogen gas.

Reprocessed:

Since I have had a good run reprocessing old DSO data sets using my current workflow and new PixInsight tools, I decided to reprocess the Helix Nebula as an HOO false color image.  I used Russ Croman’s XTerminator suite and new tools in PixInsight.  This image took some effort to remove background issues, and Photoshop was employed to desaturate and burn background regions with color gradients or brighter regions that DBE could not remove.

Description:

NGC 7293 is a large planetary nebula in the constellation Aquarius.  Planetary nebula form when a star the size of the Sun nears the end of its life as a red giant.  Nuclear fusion in the core of the star slows and gravity wins over the outward pressure from the heat and radiation of nuclear fusion.  The core collapses and the resulting shock wave pushes the expanded gas and plasma of the red giant outwards at high velocity.  The remaining collapsed core becomes a white dwarf.  The radiation from the white dwarf illuminates the expanding cloud.  NGC 7293 is about 2.5 light years across, and it is only 650 light years from Earth (SkySafari6 Pro).  It is about 10,600 years old.

The term planetary nebula is a misnomer.  William Herschel coined the term “planetary nebula” since these objects looked like fuzzy planets with some color, similar to the newly discovered planet Uranus.  Herschel missed the Helix Nebula, as it is large, spreading out the light.  Karl Harding discovered it in 1824 (SkySafari6 Pro).  While planetary nebulae are quite common in the Milky Way galaxy, most are very small.  NGC 7293 is one of the largest in our galactic neighborhood.  In about 5 billion years, our Sun will experience the same fate.

Imaging details:

Celestron 9.25" Edge HD SCT with 0.7x focal reducer and off-axis guider
Celestron CGEM II mount
ZWO ASI 1600MM Pro cooled monochrome camera (-10C)
36mm ZWO Hydrogen-alpha, Oxygen-III

Software: Sequence Generator Pro, PHD2 guiding, Celestron CPWI mount control, 
PixInsight and Photoshop CC 2020/2023

Hydrogen-alpha    5 min x 68 subframes (340 min), Gain 139, Offset 21, 1x1 binning
Oxygen-III    5 min x 62 subframes (310 min), Gain 139, Offset 21, 1x1 binning

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