Tips for Post-Processing Your Constellation Photos

Photography Tips

Digital photography is a boon for amateur star photographers. It was next to impossible to capture and then post-process details in film the same way it’s possible in digital. Certainly Lightroom and Photoshop do come into the picture, making it possible for even beginners to create stunningly beautiful compositions of the night sky, but the process starts with capturing the images. The final step is in developing them in the digital darkroom. That is exactly what photographer Ian Norman shows you in this video:

When photographing constellations such as the Orion, the biggest challenges are getting the right white balance and handling digital noise. Norman uses multiple exposures and then stacks them together to reduce noise. He also uses a method known as LRGB (Luminance, Red, Green, Blue) to ensure that the colors are enhanced.

Recommended Gear for Shooting Orion

• Any standard camera with manual shooting options (APS-C, full-frame, 4/3)
• 50mm prime lens (for full-frame sensors), 35mm prime lens for APS-C sensors, and 24mm lens for 4/3 systems
• Lens with a maximum aperture of at least f/2
• Tripod

Recommended Settings for Photographing Constellations

Recommended focal lengths and camera settings for astrophotography.

• Shutter speed of 10 seconds
• Aperture f/2 or lower
• ISO 3200 or higher

Norman recommends capturing at least 32 separate exposures to ensure you have enough data for the final image.

Development Process

The complicated and detailed development process involves the following steps:

• Importing all the images in Lightroom.
• Tweaking white balance, noise reduction, and vignetting to make the images flatter in appearance and devoid of any color cast.
• Syncing all the images so that the changes done to the first image is applied to all the other images.
• Opening the images in Photoshop through the Photomerge dialogue. Uncheck Blend Images Together and allow it to open the images.
• Convert the images to Smart Objects by right clicking and selecting Convert to Smart Object.
• Next step is to stack them together using Layer> Smart Objects> Stack Mode> Median.
• Flatten the image once the changes are to your liking.
• The next step is to execute the LRGB processing.

LRGB Processing

This process involves creating a high contrast black and white luminance layer and then combining this layer with another layer that contains all the colors to complete a high contrast color image. Please note all these steps may or may not be applicable to your particular image. You may choose to skip the ones that you feel is unnecessary.

• The first step is in using a Curves Adjustment Layer so that you can pull down the shadows and boost the highlights.
• Norman next uses a gradient tool to even out the luminosity at the lower part of the image. But before that he uses a Levels Adjustment Layer to reduce the brightness.
• If the image now appears evenly balanced you can convert all the layers into a Smart Object.
• This smart layer is copied three times over for three separate treatment. Norman marks them as Luminosity, Detail, and Color.
• Norman starts with the Color layer first, using Filter > Noise > Dust & Scratches to eliminate most of the stars except the really bright ones. He also adds a Gaussian blur to the layer to smooth it out. When finished, this layer will look subdued in the sense that finer details will be missing.
• The next layer to work with is the Detail layer. Norman gives this layer a black & white treatment and then adjusts the color sliders to bring out more contrast.

The details layer being given a black & white treatment

• To further enhance the contrast, add a Curves Adjustment Layer.
• The final layer is the Nebulosity layer. This one’s all about the Nebula. Norman gives this a black & white treatment. Additionally, just as with the detail layer, he uses the dust and scratch filter to remove all the finer details to leave just the nebula.
• The final steps involves merging each of the color, detail, and nebula layers and fine tuning them using various tools native to Photoshop to create the final look.