Thursday, July 28, 2016

Summer Milky Way over Skyline Drive

“Summer Milky Way over Skyline Drive”, Beagle Gap overlook at Shenandoah National Park. July 9th, 2016. Three panel mosaic, 30 second exposures at ISO3200 (sky), one 180 second exposure at ISO800 (foreground), Canon 550D, Rokinon 16mm f/2.0 lens at f2.4, Vixen Polarie Sky Tracker at 1/2 sidereal rate (sky) and fixed (foreground). Full resolution version here:  
Here is an image of the Milky Way over Skyline Drive in Shenandoah National Park, taken from the Beagle Gap overlook soon after I captured my panorama over Rockfish Valley in early July. I was thankful that I had purchased an annual pass to the park a few weeks earlier because I could visit my favorite place in Virginia at any time. On this occasion, I arrived around one in the morning, a little tired but determined to capture the night sky over the Blue Ridge Mountains. As I drove north along Skyline Drive I had to slam on the brakes at least four times as adolescent raccoons darted across the road, sending expensive camera gear tumbling around in the trunk.

After a short drive into the park I arrived at the Beagle Gap overlook, where I hopped out to scan the view and make sure the Milky Way was in a position that complimented the landscape. Indeed, the view was magnificent. The Milky Way arched from Bucks Elbow Mountain in the north and descended into Skyline Drive in the south. Perfect! When I returned to my car to shut off the engine I realized that I was more tired than I thought because I had left the car in drive and had only applied the emergency brake. Let’s put this another way...I almost let my car drive itself off the side of a mountain!

I quickly sat up my gear and began capturing a three-panel mosaic of the view along Skyline Drive. The teapot asterism in Sagittarius was perfectly framed between the trees at the time, but ultimately it was overwhelmed in my picture by the countless stars of the Milky Way.  My whole strategy for framing the mosaic was fraught with rookie mistakes (technical details below), in part because this was only my second attempt at a multi-panel image but also because the silence of the park, though peaceful any other time, was a bit unnerving in the darkness. Just an hour earlier I had visited Raven’s Roost along the Blue Ridge Parkway where the wind howled and shook the trees, yet here a perfect silence was interrupted only by the sound of a twig breaking occasionally in the woods…and nothing else. As any Virginian knows, the Blue Ridge Mountains is home to the densest population of black bears in the eastern United States. This fact was hot on my mind each time a twig broke. Every time I go imaging I have a bright flashlight in my pocket which I’ve named the “WTF was that!?” light. You better believe I had that thing blasting into the darkness at each tiny sound!

Once I finished capturing the view to the south and realized that bears probably weren’t pacing along the outskirts of the overlook, I turned my attention to Bucks Elbow Mountain to the north. By this time clouds had rolled in overhead which then scattered light pollution from Charlottesville and Shenandoah Valley, hence their orange color. I captured a six panel panorama spanning the overlook on the left to Charlottesville on the right. The Andromeda Galaxy is visible toward the middle which is pretty cool. I’m not too crazy about this image though because the color cast on the clouds is not very attractive in my opinion. The location is nice, so I may attempt this scene at another time.

“Starry, Cloudy Night over Bucks Elbow Mountain”, Beagle Gap overlook at Shenandoah National Park. July 9th, 2016. Eight panel mosaic, 30 second exposures at ISO3200, Canon 550D, Rokinon 16mm f/2.0 lens at f2.4, Vixen Polarie Sky Tracker at 1/2 sidereal rate.
Between these shots and my panorama over Rockfish Valley, I had three nightscapes in the bag, which is a successful night given the months of cloud-cover we have endured. I packed up and headed out of Shenandoah National Park around two o’clock, dodging a few more raccoons along the way. After a long, sleepy drive, I arrived home three hours later, ready for some well earned rest and overjoyed with the incredible night I experienced in the Blue Ridge Mountains.

Technical notes:
The Skyline Drive image is a mosaic of three images tracked at ½ sidereal rate at high ISO for the sky and one stationary shot at low ISO for the foreground. I generated two panoramas, one with the three sky images and the other with two sky images and the low ISO foreground image. I must have moved the foreground exposure slightly with respect to the sky images because the two panoramas did not line up perfectly after stitching. Even more difficult, the panoramas are made as stereographic projections so I had to warp and scale the panorama with the foreground to make it match up with the high ISO sky panorama. Looks like I need to plan these types of shots more carefully. The sky and foreground are processed separately, boosting the shadows in the roadway and modestly increasing contrast in the sky. I corrected the light pollution color cast at the very top of the image using a method suggested by Roger Clark which worked out really well.

Processing Workflow
(LR) Lightroom, (ICE) Microsoft Image Composite Editor, (PS) Photoshop CC, (PI) Pixinsight
"Summer Milky Way over Skyline Drive"
1. Raw conversion: correct lens distortion, exposure -0.75 (sky) -1.0 (foreground), blacks +20 (sky) +60 (foreground). Export individual panels as sRGB 16-bit .tiffs (LR)
2. Stitch panels tracked sky photos into panorama and also two upper tracked sky photos with lower stationary foreground photo into panorama (ICE, stereographic projection)
3. Open two panoramas as layers and align using warp/scale tools (PS).
4. Generate foreground selection by duplicating foreground layer, adjusting exposure offset, gamma correction and brightness to darken the foreground and brighten the sky. Use magic want to select foreground and then select/similar. Convert to mask. (PS)
5. Apply mask to foreground image such that only foreground portion of that panorama is visible. (PS).
6. Correct light pollution in sky by selecting a small area near the top-left away from the Milky Way and lowering the black point of the green and red channels until the left side of the RGB histograms lign up (PS, Curves adjustment layer with mask protecting foreground).
7. Contrast curve for the sky (PS, Curves adjustment layer with mask protecting foreground).
8. Increase overall exposure (PS, Brightness/Contrast adjustment layer).
9. Noise reduction (PI, ACDNR to lightness and chrominance, iterations reduced to 2 in lightness, lightness mask enabled, also applied a range mask permitting only 20% of noise reduction in foreground since I primarily wanted noise reduction in the sky).
10. Increase color saturation (PI, ColorSaturation, excluding green with lightness mask).
11. Increase foreground brightness (LR, Shadows +50)
12. Crop (LR)
13. Export as .tiff, jpeg (LR)

"Starry, Cloudy Night over Bucks Elbow Mountain"
1. Raw conversion: correct lens distortion, chromatic aberration, exposure -0.5, blacks +0.25, tone curve to boost foreground brightness (LR).
2. Stitch panorama (ICE)
3. Noise reduction (PI, TGVDenoise to Lightness, strength 5, edge protection 3E-4, iterations 200, extracted lightness as local support and inverted lightness as mask).
4. Correct light LP by lowering G and R curves until RGB histogram peaks align based on a sky-only selection near the top (PS)
5. Increase contrast (PS, Contrast)
6. Desaturate strongly scattering LP yellow near horizon (PS, saturation adjustment with color mask selecting yellow).
7. Increase foreground exposure (PS, exposure adjustment with mask selecting foreground).
8. Increase overall exposure (PS, exposure adjustment)
9. Crop (PS)
10. Fill in a small section where the images left a gap in the foreground grass. I am very uneasy with doing this and don’t plan to make a habit of it, so don’t tell anyone! (PS, duplicate layers and shifting to place grass from another location to where it is missing).
11. Reduce green cast (PI, SCNR to green, 0.15 w/ range mask protecting foreground).
12. Export as .tiff, JPG


  1. Just beautiful. I was just hiking that spot a couple of weeks ago. I totally missed all the night beauty. Your hard work is evident and appreciated. Thank you for sharing them!

    1. Thanks a lot, Kim! It is so great to have such a wonderful national park in our state!

  2. Jason, Great job!! I am trying to capture your work flow so that I can try it with some of my images. Your web site format of white type on a black background makes this very difficult (I have to fat finger your text). In the future will you please type on a white background. Thank you