The Dolphin Breathes in Green: Sh2-308 Beneath a Dark Desert Sky

Adrift in the winter constellation Canis Major, the Dolphin Head Nebula (Sh2-308) glows softly in oxygen-rich green, its arc sculpted by stellar winds racing through interstellar space. This vast bubble, nearly 60 light-years across, was carved by the intense outflow from the massive Wolf–Rayet star EZ Canis Majoris, whose powerful winds collide with surrounding gas, causing it to fluoresce in narrow wavelengths of light—especially doubly ionized oxygen.
This image is the result of 95 long exposures, each 600 seconds, captured under a pristine Bortle 2 sky in the Sonoran Desert. Such dark skies are essential for revealing faint nebular structures that are otherwise erased by light pollution. From midnight until dawn, the cold desert air sharpened both the stars and the resolve of the observer, allowing delicate shock fronts and subtle color gradients to emerge.
Beyond its beauty, Sh2-308 reminds us that dark skies are a finite natural resource. Preserving them allows humanity not only to explore the cosmos scientifically, but also to reconnect with the deep night sky that has inspired discovery, wonder, and perspective for millennia.

>Telescope: Celestron Nexstar Evo 9.25 235mm f/10 Schmidt Cassegrain
>Camera: ZWO-ASI2600MCPRO
>Mount: Sky-Watcher EQ-6R Pro Computerized Equatorial Mount S303000
>Guide Scope: ZWO 30F4Miniscope
>Guide Camera: ZWO ASI462 MC Planetary Camera
>Starizona Hyperstar 4HS4-C9.25 white 10014
>ZWO standard Electronic Automatic Focuser EAF-5V
>ZWO ASIAir Plus Wifi Camera Controller
>Optolong- L-Pro 2” multiband Pass Filter
>Samsung Cellular Phone
>Memory Card

Images were stacked in Deepsky Stacker, processed in Pixinsight and Photoshop