In this tutorial I will show you how to stitch and edit your Milky Way panorama photos with some basic editing techniques in both Adobe Lightroom and Photoshop CC.
I captured this 9 image panorama near Hout Bay, South Africa, and although there was quite a bit of light pollution generated from the town, I was still able to capture decent detail of the Milky Way core. I shot a 4x2 panorama, which means I took 4 photos on the same level for the foreground and then 4 images above those for the sky (Milky Way). The reason I have 9 images in this panorama is because I took an extra image of the town on the right which had a little more foreground I wanted to add in. All the other images were taken at 13 seconds, f1.8, iso800. If you want to learn more about taking astrophotography images and which settings to use, please see some of my other articles. This article will focus on stitching and basic editing.
Remember that there are many different ways to do what I'm showing you here and that this is just one way to stitch and edit your photos.
Once you've imported your images into Lightroom CC, select your images and right click.
Click on Photo Merge and select Panorama.
The Panorama Merge Preview option window will open and automatically generate a preview thumbnail on the right for you to see. Select Spherical and leave all other options unchecked. Don't be surprised if your panorama looks all weird with a very curved horizon. This is normal and we will correct this shortly. Once you're happy that all the images have been incorporated into the merge and the image looks correct, click the Merge button on the bottom right.
Lightroom CC will take some time to merge all your images together. Once it's done, right click on the merged image and go to EDIT IN and select edit in Adobe Photoshop CC.
Once you've opened your file in Photoshop CC, select the Filter menu at the top of the screen and click on the Adaptive Wide Angle Tool.
Select the perspective correction on the right (you can try different correction options under this image as some options work better for different distortion issues), slide the Scale slider so that the entire image fits onto the grey zoned area and that none of your image is cut off. Set the Focal Length used and the Crop Factor As Shot. This will correct a lot of the distortion of the Milky Way. You'll already be able to see that the Milky Way is less compressed from the top compared to the previous image.
Now select the line tool on the left (it's the tool on the top). Click on one end of your horizon and move to the other end. You'll see the line will follow the curved contour of your horizon. Once you click on the other end of the horizon, the software will automatically straighten the horizon for you. You can then use the circle (by click and dragging the dot touching the circle) to adjust the angle of your horizon. Once you're happy with this step, click OK.
This step may take a few attempts to get right, but it's worth taking the time to get familiar with it as it can be used to correct distortions on all types of landscape images.
Now select the crop tool on the left hand Photoshop panel and crop any excess parts of the image you don't need. You don't need to crop all the grey areas (areas with no image) otherwise you'll loose large parts of your panorama. I'll show you in the next step how to fill those in.
Try to keep the areas without any image information to a minimum, but you'll normally end up with a few little areas in a panorama that need to be filled in, generally in the sky. Now select the lasso tool from the left panel and circle the blank area as close to the edge as possible. Then click SHIFT & F5 at the same time. This will open Photoshop's Fill content-aware tool (this can also be found under the Edit menu and Fill option). Make sure under Contents it is set to Content-Aware and Color Adaptation is selected (see image below). Click OK.
You'll see now that the area is automatically filled with information from the surrounding areas. Note that if your area is too large, the content-aware may not have enough information to completely fill the gap and may look strange. If this happens you'll have to use other gap-filling techniques such as clone stamping.
This method can also be used to remove unwanted elements from an image such as pollution or people.
Now that all the gaps are filled, we have the final file for editing. See below my merged image with no processing done on it. You can clearly see the Milky Way detail even though it's faint in certain areas.
In this next part I'll show you some basic editing techniques to enhance the information of your RAW file. So now click the File menu in Photoshop CC and click on Save. The file will then automatically be present in your Lightroom CC library next to the file you originally imported.
Click on the Develop tab next to Library in Lightroom CC (top right of screen) and select the image that you saved from Photoshop CC.
The first thing I want to correct in this image (as much as possible) is the bright lights from Hout Bay in the bottom right. To do this I select the radial filter tool (the circle in the same row of tools as the crop button) and drag a circle over the bright area. I then adjust the feather to 100% and select invert (so that I'm only selecting inside of the circle). Next click the Range Mask and select luminance. Click Show Luminance Mask (see image below) and adjust the range and smoothness so that only the area you want to adjust is selected in red. Once you're happy with your area selection, unclick the show luminance range mask so that you can see your adjustment effects. Now you can make adjustments using the sliders. You can see the area I selected in the image below and the only adjustment I made was reducing the highlights by 20%.
For this image I won't be able to reduce a lot of the highlights as I've overexposed most of the town lights, so there isn't any information for me to pull back in this area. Typically, if I have a very bright area such as this, I may consider shooting an image at a much lower exposure that doesn't blow out the highlights and blending in just the lights. But that's for another more advanced tutorial. For now I'm just demonstrating to you several techniques you can use to fine-tune areas of your image.
Next select the graduated filter tool and drag it over the darker foreground areas of your image. Now you can lighten the foreground and bring out some more of the detail there. For this image I increased my exposure, shadows and whites slightly and decreased my black areas (see image above on the right). The red area above shows you the area you're affecting. The further apart the lines are dragged, the softer the transition.
Next I want to enhance the light areas in the Milky Way core to make them stand out a little bit better. I use the same method as previously with the radial filter tool and select only the bright areas in the Milky Way (see above). I increased my highlights, whites and clarity between 5-15% and added a slightly warmer temperature to the highlights to add some colour back into the Milky Way core.
Lastly, I adjusted a few global settings to my image to finish it off. These can be seen on the right hand panel in the image below. You may find when shooting the Milky Way near the ocean or humid areas that you have to use the dehaze tool to reduce the haze in the air. I only increased the saturation by 9% and adjusted the highlights and shadows until I has happy with the level of detail in the image.
You'll find that because you're shooting at a high ISO for astrophotography, you will need to use the noise reduction slider. Adjust the the luminance slider under Noise reduction to between 15-30% depending on your ISO. If you go higher than that, your image will lose a lot of detail and look blurry.
Lastly, select Remove Chromatic Aberration and add a little bit of a vignette to darken the corner of your images. This will help draw the viewer's eye to the centre of the image.
Remember these are a few examples of how to edit your Milky Way images. You could spend a lot more time fine tuning all the settings and do a lot more localised area edits. This tutorial is just to give you a basic idea of how to edit your Milky Way panorama image from a bunch of photos to a final product.
I hope this was helpful to you and that you at least learnt something new. If there's anything you want to ask or any feedback you want to give, please let me know know by commenting on this article or by sending me an email to firstname.lastname@example.org.