Capturing the Cosmos: My First Milky Way Mosaic in Yosemite

As a budding astrophotographer, there's something incredibly rewarding about finally getting a clear view of the Milky Way. My recent trip to Yosemite National Park provided the perfect backdrop for my first mosaic and a serious attempt at capturing our galactic home.

The Journey to the Stars

The allure of the night sky in a place as breathtaking as Yosemite is undeniable. Away from the light pollution of the city, the stars truly come alive. This experience was all about pushing my skills and equipment to their limits.

Gear Up!

For this ambitious project, I relied on my trusty OM-1 camera paired with the versatile 12-100mm F4 PRO lens, set at its widest at 12mm and F4. This combination offers a great balance of wide-angle capability and light-gathering power, essential for capturing faint celestial details.

The Mosaic Technique

To achieve a sweeping view of the Milky Way, I opted for a mosaic approach. The final image is composed of 5 slices, with each slice consisting of 5 individual shots. This brought my total shot count to 30, a significant undertaking that requires careful planning and execution.

Exposure and Settings

Each frame was captured with an exposure of 8 seconds at an ISO of 3200. These settings are crucial for balancing the faint light of the stars and the Milky Way while minimizing noise and avoiding star trails.

The Art of Processing

Bringing the raw data together into a stunning final image is where the magic truly happens. Here's a breakdown of my processing workflow:

Stacking and Freezing Background: I used Sequator for stacking the individual frames. This process helps to reduce noise and enhance detail. I also utilized its "freezing background" feature, which is vital for panoramas.
Denoising: GraXpert was my go-to for intelligent denoising, helping to clean up any remaining noise without sacrificing crucial detail.
Color and Contrast: A simple curves adjustment in GIMP was used to fine-tune the contrast and bring out the subtle colors in the sky.
Stitching the Panorama: The individual slices were expertly stitched together using Hugin to create a seamless wide-field view.
Star Removal and Enhancement: For the most critical step of separating the stars from the background, I turned to SIRIL with Starnet++. This powerful combination allowed me to remove the stars and then adjust the Milky Way background separately. Finally, I recombined the stars and the enhanced Milky Way in SIRIL to achieve the desired final look.

A Glimpse of Airglow

One of the most exciting discoveries during this process was the presence of what I believe is airglow on the left side of the image. This faint, natural emission of light in the Earth's upper atmosphere adds another layer of depth and wonder to the shot. While the image might appear slightly dark, I'm considering further adjustments to bring out more detail, especially in those faint celestial features.

Living closer to a city can indeed make seeing the Milky Way a challenge, but moments like these, especially during a camping trip, remind us of the incredible beauty that awaits when we escape the urban glow.

Milky Way in Yosemite