Milky Way Over Lake

Image Critiques Nightscape & Astro Critiques
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2022-06-04-Stack-002.jpg
2022-06-04-Stack-002.jpg2002×2803 603 KB

Critique Style Requested: In-depth

The photographer has shared comprehensive information about their intent and creative vision for this image. Please examine the details and offer feedback on how they can most effectively realize their vision.

Self Critique

This is the first take of an idea I’ve been working on for a couple of years. I’m happy with the general composition but not so much with the technique (reflection of the MW in the lake) or final processing (the very green sky is noticeable in the RAW images with very little color correction in the final image).

I’ve been focused on improving my nightscape images for about three years now, so any feedback is appreciated, even if it’s beyond what I’m asking for here.

Creative direction

The basics for what I’m going for are here - a vertical, detailed MW reflected in the waters of the lake. For the reflection in the lake I’m not concerned about clarity of details, but the reflected light, however distorted, should mirror what the viewer sees in the sky. As for color, I try to get somewhat close to the true colors of the MW.

Specific Feedback

When it comes to shooting a reflection of the night sky in a body of water like this, what techniques are used to keep the two images temporally matched? There are two issues I’m running into: (1) the night sky is a set of tracked images and (2) the foreground is a single long exposure which ends up with the stars trailing. As a result, when I blend the sky and foreground together they are separate in time and they don’t align. I have to rotate the sky to try and match the mirror image I see in the lake. This was much harder than I expected, so I’m wondering if anyone has some tips on how to make this easier. I’m not too concerned about the star trails in the reflection, the lake isn’t still so I think it makes this less noticeable. (Out of curiosity, do the results here look “off”, or does it look like I matched it up fairly well?)

I’m puzzled by the green sky. I returned a couple of years later and got similar results, but I haven’t seen this show up in other pictures I’ve taken. Usually the color tends to be cool blues or warm yellows. I shoot with my camera white balance set to daylight exposure. If I adjust the green channel it looks better, but I then end up with a maroon cast which isn’t what I’m going for, either (and I get some weird color fringing around the trees where I blended in the two images which isn’t ideal). Some pointers or help on how to adjust the color would be appreciated.

How does the blending look at the horizon? If anyone uses Affinity Photo, I’d love to hear how you go about blending. I have a workable method, but it’s pretty tedious. (Although, to be fair, I am blending in pine trees so I’m just asking for it…)

Technical Details

Camera: Nikon Z7
Lens: Nikkor Z 20 mm f/1.8S

Sky:

  • 15, 30 second exposures at f/1.8 using a tracker
  • Preliminary light processing in Capture One, then tiff images are stacked in DeepSkyStacker
  • Capture One used to process the final stacked image

Foreground:

  • 1, 2 minute exposure at f/1.8 shot after the tracked images
  • (Green color cast to the sky is visible in this image)

Final Processing

  • Sky and foreground blended in Affinity Photo

Description

Located up on the Mogollon Rim, this lake is a favorite place of mine to go in the summer. One year I realized it aligns well with a vertical MW, so I’ve made two attempts now, this one and another attempt last year. (As a side bonus, you can take pictures of the ospreys fishing the lake when night gives way to morning, so I take my telephoto lens, too!)

There’s a brief window of opportunity in early summer before the summer monsoon rolls in and brings with it cloudy night skies in the high country. Late May and early June are the best times to shoot. I’ll likely try again this year unless the forests are closed due to the abysmally dry winter we’ve had. I’m really happy with the composition but I would like to get a better quality image, with the colors more closely aligned to my perception and a better reflection. When I try this again, I’ll have a wider lens (Sigma 14mm f/1.4).

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A very brief reply with initial impressions for now and more later… First, it’s great to have a new participant here! Welcome!! The rotation/alignment looks good to me and I wouldn’t have thought it was over some time span. I love the composition!

I’m puzzled by the green, too. Daylight should be best for accurate star colors and I do see some color here, especially in the reflection. And the galactic center should be a warm color. My only (very undeveloped) thought for now is that when I process a tracked stack in PixInsight (even with a dedicated astro camera) there is a strong green cast which is routinely neutralized early in the process. I’ve never questioned it (nor seen anyone else do so), but wonder now if it’s somehow a sensor thing? If nothing else, some sort of neutralization kludge should sever you well here, then lean it toward blue a bit if desired. The debayering is matched to the sensor so that’s not the issue.

A month earlier and later in the night should give a slightly better alignment with the Milky Way a little to the left. I always like to see room given to Antares and the Rho region, which are just touching the trees on the right edge here.

Going off in a dark corner to think about this! I’ve only barely used DSS but haven’t seen greens like this. If anything,I’ve seen low contrast and saturation. I’d love to see if others here can comment!

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@Diane_Miller, thanks for the preliminary feedback!

Your suggestion to shoot a month earlier got me to thinking about the composition and ways to improve it. I see what you mean. At the very least, a little bit of easterly tilt to the galactic plane could help balance the image a bit. I’ll check alignments and see what works.

I thought the green tint might be sensor related, too. But I’m also wondering if it might be location related. There’s a town to the southwest that’s providing the glow on the horizon; maybe that coupled with dust and moisture in the air is creating the color cast? I haven’t seen a similar color cast at other locations I’ve done nightscapes. Closer to Phoenix the sky tends to be dominated by a yellow tint. Deeper in dark sky country (up on the north rim of the Grand Canyon) I get a blue or purple tint.

As far as stacking goes, looking at other posts in this category I see you’ve mentioned PixInsight and Sequator. I’ve used the latter but not the former. I’ll have to check it out. Unfortunately I lost my RAW files for this image when my computer crashed a couple years ago, so I can’t try reprocessing. I still have the old hard drive; I salvaged what I could. Maybe I’ll see if a professional with better tools can recover what I couldn’t.

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Possibly the green is airglow – a normal occurrence in the night sky. (There is a good Wikipedia entry on it.) It is variable, but not usually this extensive. Maybe there was some large event this night? At any rate, there is wide acceptance is the astrophotography community to “normalize” colors. I think there is good understanding there of the difficulty of capturing “accurate” color.

PixInsight is well worth checking out but it makes Photoshop look like a kid’s coloring book. It is constantly evolving new “processes” and there is a confusing array of tutorial material – mostly videos. They come in three varieties:

Those that are so out of date that they do more harm than good, but no way to find out up front.

Those done by people who know what they are doing so thoroughly that they skip over the basic steps that are vital for those who don’t know what they are doing. (“Wait, what did he click to get that…?”)

Those done by people for whom English is a fourth language or by people with a significant speech defect. These can be entertaining to watch because the closed captions can’t understand the guy any better than you can.

Good luck with the drive recovery – in many cases it can be successful.