It's been my baby project to capture full Milky Way Arch with Mt. Shuksan in center reflection on Picture Lake at Mt. Baker since we went there to capture Milky Way and Northern Light in July. One of our photo team asked me how we can capture the Milky Way in Arch form. I thought it can be captured by a fisheye lens but other team member indicated it is captured with panorama stitching. I started researching on the technique and Milky Way position and end up being a quite project.
Through my research, I found August 31st through September 5th are ideal timing to accomplish the project tasks. Please refer to following plan sheet. http://.../d977046660.pdf
Result #1: This image was taken on August 31st, 2013 around 10:30pm. Because it was Saturday evening, there were some artificial lights from a cottage in Mt. Baker Skiing Resort which shed the trees across the lake.
Milky Way position:
The azimuth ange of the peak of Mt. Shuksan from the main view point at Picture Lake is 124.4 degrees. On the 31st of August 2013, the Milky Way shows up with bright side at south and the other end at northeast around 20:45. The Milky Way moves 15 degrees per hour and reach the ideal (1/3 east from south meaning azimuth angle 120 degrees) around 22:30. A free PC application STELLARIUM is very helpful finding the angle of Milky Way and other stars/sun/moon. The position of Milky Way changes every minutes and starting angle varies day by day. We will need to avoid bright moon days especially the moon gets into the scene. September 5th is new moon day and on the 31st of August the moon was hidden under horizon.
Based on my research, following days and time will be good for same subject at Picture Lake in 2014.
Photo shooting technique:
Three important factors need to be considered. #1/Exposure, #2/Focal length, and #3/Panorama scanning.
Exposure setting: the same as typical astrophotography. ISO 2500-3200, f/2.8, 25-30sec, White Balance 4760K.
Focal Length: I've used 14mm lens. Theoretically, 17mm should be also OK to use. The Milky Way runs almost above your head requiring coverage of over 180 degrees horizontal and over 120 degrees vertical. This ultra wide landscape cannot be captured with a single shot (except for the ones with a fisheye lens). We will need to capture multiple images and stitch together. Initially, I thought 9 images (3 vertical and 3 horizontal) are sufficient to cover, but after I made trials in day light condition I realize that 15 images (3 vertical and 5 horizontal) images are necessary for the software to be able to stitch together. (Please note that my Plan sheet indicates 9 image sequence but this does not work well.)
Panorama scanning: As you can see in my planning sheet, it is required to cover 180 degrees vertically and 200 degrees horizontally. The center image of scanning should direct towards 15-20 degrees upward. I've used a tilt base on the tripod, then a ball head, then panning head. I've marked up -60 degrees, center, and +60 degrees horizontally on a ball head. I've used these markers to position -60, -30, 0, +30, and +60 degrees. The bottom sweep uses about horizontal level and top sweep used mechanical limit of the ball head, and center sweep is in the middle point of both. As the ball head base is tilted, I adjust vertical angle at 0 degree angle first, the move to -60 degree, -30,,,,, the +60 degree starting with the bottom, then middle, and then the top sweep. Since each image takes at least 30 seconds, it will take approx 10 minutes to take one group of 15 images. During this 10 minutes the Milky Way and stars move 2.5 degrees [(360x10)/(24x60)=2.5], stitching is becoming a little bit of challenging for the software. The quicker to complete the better but I do not know if we can accomplish faster than 10 minutes per one photo groups. I think it is important to keep consistency when you sweep and capture those 15 images in terms of optical axis and swivel angles for the software to be able to get consistent result. (Please note that stitched 15 images will be heavily distorted since we are capturing 3 dimensional ultra wide object in a single 2 dimensional form.)
Post shooting processes: I am using LightRoom and Photoshop. Other photo editing software should be able to accomplish the same or similar processes as mine After download and added images to the catalog, apply basic adjustment such as Exposure, Hightlights, Shadows, Blacks, Clarity, Tone Curve, Noise Reduction, Lens Correction, and so on. I found it effective if I apply Lens Correction/ Profile /Enable Profile Correction / Amount 100% before moving to stitching process. I usually create small size files (1500x2250) in JPEG for testing of stitching process. For the stitching, I am using Photoshop / Automate / Photomerge function which it will merge (stitch) those 15 images into one automatically. With the result of small size (1500x2250) testing, I will examine the stitching result, final photo parameter adjustment, and distortion. Once photo merge is complete, another test is if I can distort the image to presentable form ( especially the horizon line straight) by using Photoshop / Edit / Transform / Warp function. If it works well enough to your satisfaction, repeat the processes with large format TIFF image files in order to create your final artwork master file.
Result #2: Taken on September 10th, 2013 around 9:10pm. It contains some bluish sky color from very tiny bit of sun light from below horizon. Also the setting moon lights from southwest sheds the top of Mt. Shuksan.
Result #3: Taken on September 10th, 2013 around 9:20pm. It looses bluish sky color but still some remains.