Melotte 15: A Stunning Narrowband Astrophotography Deep Dive

Welcome back to the blog! Today, I'm thrilled to share my latest deep-sky project: Melotte 15. This has been my most ambitious integration to date, spanning an impressive 33 hours and 31 minutes. As someone who's been actively pursuing astrophotography for just over a year, and delving into monochrome imaging since April, this project has truly pushed my boundaries and solidified my love for narrowband imaging.

Living in a Bortle 5-6 zone near a capital city makes narrowband imaging essential, and the ability to pull such a rich spectrum of colors with different filters is nothing short of magical. The SHO palette, in particular, allows us to visualize nebulae in ways our eyes simply cannot perceive, mapping specific emission lines to striking colors.

The Image

Melotte 15

Imaging Details

Total Integration: 33 hours 31 minutes
For Nebula (SHO Palette):
- Sulfur II (S II): 128 x 5 minutes
- Hydrogen Alpha (Hα): 128 x 5 minutes
- Oxygen III (O III): 127 x 5 minutes
For RGB Stars:
- Red (R): 11 x 3 minutes
- Green (G): 11 x 3 minutes
- Blue (B): 10 x 3 minutes

Equipment

Telescope: Askar V (80mm) with Extender (600mm focal length)
Camera: QHY MiniCam8
Mount: Sky Watcher Wave 100i Strain Wave Mount
Focuser: Gemini Electronic Auto Foccuser
Guide Scope: ZWO 30mm
Guide Camera: ZWO ASI 120mm Mini
Accessories: SVBony SV241 USB/Power Hub, Jackery 500
Processing Machine: Mele Quieter 4c (N150, 32GB RAM)

Software & Processing

Acquisition: N.I.N.A.
Guiding: PHD2
Stacking & Processing: PixInsight
- BlurXterminator
- NoiseX & StarX
- Narrowband Normalization
- Selective Color Adjustment

The Magic of the SHO Palette

Many of you might wonder why the image appears so vibrant and colorful when capturing nebulae with narrowband filters. The reason lies in how we assign these specific light emissions to colors. In essence, the SHO palette maps Sulfur II emissions to red, Hydrogen Alpha to green, and Oxygen III to blue.

Our eyes, particularly the cones responsible for color vision in low light, perceive these emissions as a dull grey. However, by dedicating extended exposure times with specialized filters and then mapping these captured emissions to the visible color spectrum, cameras can reveal the breathtaking beauty and intricate structures that are invisible to the naked eye. It's a testament to the power of technology and careful processing in unlocking the universe's hidden palettes.

See More

For those interested in exploring this image in higher resolution, you can find it on my website here: .

I hope you enjoyed this glimpse into the detailed process of capturing and processing Melotte 15. What celestial objects would you like to see me tackle next?