For this image I used a Sony A7III camera and a Sony 35mm f/1.4 lens. The camera I had astro-modified by removing a stock filter so it would be sensitive to red wavelengths present in the nebulae.
The image is a combination of three separate images: one two-minute exposure of the land, plus two images of the sky: one full spectrum and one only capturing light in the wavelength of the hydrogen alpha. For the sky images, the camera and lens sat on a star tracker, a portable mount that counters the earth’s rotation allowing for long exposures without star trails.
I shot an hour worth of 60s exposures with this set-up. I then added a filter which only allowed light in from the very specific wavelength of light in nebulae and stars (H-alpha) and shot another hour of 60s exposures with this filter. This allowed me to bring out in great detail areas of emissions in the Milky Way that would have been much fainter without this filter. After collecting all these exposures, I used a free program called Starry Sky Stacker to “stack” the images — compiling the data in the exposures together to refine the target and reduce noise.
Once I had done that with both the H-alpha exposures and the full spectrum exposures, I was able to compile the final sky image. To do this I split the full spectrum image into its individual RGB components and replaced the Red channel with the H-alpha image. With that the sky image was near final, and I only needed to make some global adjustments in Adobe Lightroom to get it to the style I wanted.
After I shot the sky, I then shot the land. Once I had all these images, I used masks in photoshop to blend all the images together for the final composite.
This is shot at 35 mm so a pretty accurate representation of the size of the constellation in the sky. The moon is around 1/2 of a degree whereas Orion from Rigel at the “foot” of the constellation to Betelgeuse at its “shoulder” is over 20 degrees. So about 40x the size of the moon.
MrJackDog OP t1_iy0q74m wrote
For this image I used a Sony A7III camera and a Sony 35mm f/1.4 lens. The camera I had astro-modified by removing a stock filter so it would be sensitive to red wavelengths present in the nebulae.
The image is a combination of three separate images: one two-minute exposure of the land, plus two images of the sky: one full spectrum and one only capturing light in the wavelength of the hydrogen alpha. For the sky images, the camera and lens sat on a star tracker, a portable mount that counters the earth’s rotation allowing for long exposures without star trails.
I shot an hour worth of 60s exposures with this set-up. I then added a filter which only allowed light in from the very specific wavelength of light in nebulae and stars (H-alpha) and shot another hour of 60s exposures with this filter. This allowed me to bring out in great detail areas of emissions in the Milky Way that would have been much fainter without this filter. After collecting all these exposures, I used a free program called Starry Sky Stacker to “stack” the images — compiling the data in the exposures together to refine the target and reduce noise.
Once I had done that with both the H-alpha exposures and the full spectrum exposures, I was able to compile the final sky image. To do this I split the full spectrum image into its individual RGB components and replaced the Red channel with the H-alpha image. With that the sky image was near final, and I only needed to make some global adjustments in Adobe Lightroom to get it to the style I wanted.
After I shot the sky, I then shot the land. Once I had all these images, I used masks in photoshop to blend all the images together for the final composite.
For more of my work, check out my Instagram: @brennangilmorephoto