Widefield of the Ara Constellation in Narrowband

A widefield view of the Ara Constellation in narrowband.

This image includes NGC 6188, above and left of center. NGC 6188 is a colorful emission nebula located in the southern constellation Ara. It is known as the Rim Nebula, but is often called the Fighting Dragons of Ara.

Below NNGC 6188 is the small bright blue emission nebula NGC 6164. It is also known as the Dragon's Egg Nebula. It is located in the constellation Norma.

As stated, this image is a narrowband image. Ionized gases in this nebula produce three prominent emissions: Hydrogen Alpha (656.3 nm), Sulfur II (672 nm) and Oxygen III (500.7 nm). I used the Hubble Palette to map these emissions to RGB image channels. These are as follows:

Red: Sulfur II (672 nm)

Green: Hydrogen Alpha (656.3 nm)

Blue: Oxygen III (500.7 nm)

Bottom line, this mapping communicates the composition of different regions in the nebula. It does not represent the way the nebula appears to our eyes.

Also the widefield nature of this image produces a rainbow of colors. There is an image of the Rim Nebula, NGC 6188, and the Dragon's Egg Nebula, NGC 6164, earlier in this album that was processed using the same Hubble palette. Those images provide a zoomed in perspective of the Hubble palette.

Image processed by Andrew Macica, original data from Telescope Live.

Imaging Details:

Observatory: Heaven's Mirror Observatory, Yass, Australia

Telescope: Takahashi FSQ-106ED

Aperture: 106 mm (4.17 inches), f/3.6

Focal Length: 382 mm (with 0.73x focal reducer)

Camera: FLI ProLine PL16803 CCD

Filters: LRGB

Total Exposure: 34 hours 50 minutes

Image Processing:

PixInsight 1.8.9-3 Ripley (x64);

BlurXTerminator, NoiseXTerminator, StarXTerminator (RC Astro);

Adobe Photoshop 25.12.4;

Adobe Lightroom Classic 15.0.1

Instruction on PixInsight from Adam Block Studios.