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This is the Rosette Nebula, an emission nebula roughly 5000 light years from Earth in the constellation of Monoceros, as photographed from my pool deck. This nebula is a cloud of, primarily, ionized hydrogen gas. It gave rise to the birth of a clump of stars forming the open star cluster NGC 2244 easily seen in the center of the object. These hot, bright stars blew solar winds and emitted tremendous solar radiation blowing a bubble in the cloud of gas and ionizing the surrounding cloud of hydrogen gas. 

To find The Rosette Nebula in the night sky, look between the stars Betelgeuse and Procyon right in the edge of the Milky Way band.


Telescope: William Optics Zenithstar 103 APO Doublet Refractor
Mount: iOptron CEM60
Focal Reducer/Field Flattener: William Optics Flat 6IIIA .8 Reducer
Camera: ZWO ASI 1600MM Pro
Auto Guider: ZWO Off Axis Guider
Guide Camera: Starlight Xpress Lodestar X2 Mono
Filter Wheel: ZWO 8-Position Filter Wheel
Ha: 26 x 10 Mins
Oiii: 24 x 10 Mins
Sii: 24 x 10 Mins
Total: 12.33 Hours

Capture Details

I photographed this object over two nights, Jan 29, and Feb 2, 2021. I set my equipment up on the pool deck in the late afternoon. I had everything set up, balanced, and hooked up to the computer and waiting on sunset for both nights. I used a computer planetarium called Stellarium for planning and target framing. I used PHD2 for autoguiding and Astrophotography Tool (APT) for session management and plate solving interface. I used ASTAP for plate solving and iOptron Commander to control the telescope. 

Shortly after sunset, Polaris (The North Star) became visible and I polar aligned my mount with the in-mount polar scope and the Polar Finder phone app. During the time immediately after Polaris becomes visible, it is still too light to get useful images. I used this time to cool the camera, navigate to a focus star, focus the scope, focus the guide scope, and synchronize the mount. Then I moved to the Rosette Nebula, started my autoguider, and set up the imaging plan in APT. By now, it is fully dark, and I launched the imaging plan.

Both nights went very smoothly. I had no equipment issues, no operator errors, and the night remained clear and cloudless. I rarely have two nights in a row where I am able to collect 6 hours of images without any issues. The raw images were high quality and very easy to process with almost no light pollution noise.

When processing the image, I tried several different color mapping palettes. While most of them were pleasing, I settled on an HSS_O color palette. This means I mapped Hydrogen (Ha) to the red channel, Sulfur (Sii) to the green and the blue channels and used Oxygen (Oiii) as a luminance layer. I used Photoshop to blend the colors and clean up the light pollution and read noise from the camera. I used Deep Sky Stacker to stack all of my 10-minute exposures and dithered between every image. The process of stacking and dithering removes almost all random noise and pollution and preserves the details collected in the photographs.

Anyhow, 5000 years ago when Stonehenge was beginning construction, the Harappan civilization flourishes in Indus, somebody started up the city of Troy, and the Egyptians domesticated camels, this nebula fired some photons towards Earth. Last night I caught some of them.


If you like this photograph and would like to see how it was done, go to the video section on the home page to see the documentation video of how I photographed the Rosette Nebula.


The Rosette Nebula

  • If you order a metal print of The Rosette Nebula, you can choose the size, surface, and finish of your picture.

    Canvas Prints come in only one finish (Flat/Matte) and one hanging option, so you will not be prompted for those options.

    Acrylic prints come with only one finish and one hanging option (French Cleat -- because of their heavier weight).

    You can order several different sizes of Metal, Canvas, and Acrylic Prints.

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