Category Archives: Creativity

Stacking: the Overloaded Word That Needs Explanation

The current rage of “stacked Milky Way” (or night sky) captures is quite different from the star trail or timestacks style of captures. Huh? The words stack and stacking are overloaded with many different meanings. Let’s see if we can add some precision and clarification.

Here are some of the variations possible:

  • Auto Blend Layers with Stacking: Used for macro/focus stacking, HDR, and generic image blending – NOT for astro images!
  • Lighten Mode Stacking: Creating Star Trails!
  • Statistics Mode Blending (Stacking): Can perform the same operation as Lighten Mode Stacking when the option “Maximum” is used, however Statistics are heavy weight and more complicated to do in our opinion.
  • Align and Stack: Deep sky astrophotography using several images taken one after another as quickly as possible. Photoshop doesn’t do this well, but we describe how in the next section. Align is the distinguishing word here.
  • Tracked Stacked Images: For still astrophotography images with less noise and greater detail. A device is required that tracks the sky rotation – the word tracked is the key here.

    Adobe Lightroom and Adobe Bridge “Stacking”

  • Group into Stack:  Not stacking at all! It really just means “create a group”.

The above is NOT an exhaustive list of the kinds of stacking you may hear about!

Stacking Types Explained

Group into Stack

Let’s start with the easy one: Stacking may mean add to group. In Lightroom and Adobe Bridge you can pick several photos and the options  Stacking -> Group into Stack. Or pick several photos and either Photo Merge to HDR or Panorama with the “Create Stack” option checked. In this context, Stacking and Stack just means group.  Unfortunately a photo can only appear in one stack, and you cannot stack photos from different folders together.

Why would you want a photo to appear in two (or more) stacks groups? Here is an example where I used a single top shot and created two different panoramas.

Panoramas 1 and 2 were both created using image 3 (608095.NEF) but when panorama 2 was created, image 3 was removed from the stack (group) for 1 and added to the stack (group) with 2. Furthermore, you can see that the panorama and the two photos used to create it were all added into the group (notice the last image says 3 of 3).

Blend Layers using Lighten Mode

Stacking may mean blend photos in lighten or darken blend mode – examples are star trails and timestacks. In this usage, the lightest (or darkest) of all the pixels in each image is selected. This is the kind of stacking that AdvancedStacker Plus does. Below is an example of taking several images that we collected over time with long delays between each exposure causing the “dotted” appearance of the star trail.

Several layers of images taken at intervals all set to blend mode “Lighten”

Align and Blend Stacking

Stacking can ALSO mean ALIGN and blend images with median, mean (aka average) or more sophisticated algorithms. Indeed astroimagers have been doing this style of blending for years using techniques that involve “star registration” (aligning stars with stars) and some pretty fancy stacking algorithms like Alpha-Kappa Median Clipping and Entropy Weighted Average. The key point here is the alignment. Indeed, here at StarCircleAcademy, we’ve explained how you can brighten and reduce noise in your foreground using simple astrophotography processing techniques.  See below for how to accomplish Align and Blend Stacking in Photoshop, and plenty of warnings about why this method is very likely to FAIL using Photoshop as the tool.

You may also see references to tracked, stacked images. These are the same as “align and blend” just described, except that to capture the image, the camera is guided by an external device (or by some fancy internal hardware), to allow longer exposures of the stars without getting unintentional trailing (smears) of stars.

The takeaway is that not all stacking is created equal. You need to know the context to understand what is meant by the word: stacking.

Focus Stacking / Auto Blend Layers

In Photoshop there is Edit -> Auto-Blend Layers -> Stack Images this is yet another kind of stacking (focus stacking) and despite the wording is NOT the kind of operation needed to ALIGN and Blend astro images. If you don’t believe us, give it a try and you’ll see it will do very weird things with your layers. Below are the same images as earlier. Note the bizarre masks it created to do the blending.

Edit -> Auto-Blend Layers -> Stack Images makes a mess. We told you so! Click to see a bigger image.


Aligned, Stacked Starry Landscape Images

While it would probably be better to make this a separate article in itself, we found it painful enough that we don’t recommend bothering – and yet we proceed to explain HOW to do it anyway!

If you want the cleanest possible images, you’ll – of course – want to reduce the overall noise  and bring out details by using many images instead of one. This approach is not all puppies and kittens. Here are some of the pitfalls:

  1. The direction of sky movement relative to the ground has a significant influence on the quality of the result (as well as the order chosen for alignment). In general, setting constellations are better than rising ones.
  2. Most of the existing tutorials will assume that you have a recent (CC) version of Photoshop with statistics and an an “Auto Align” that properly manages masked regions.
  3. Some of the tutorials we’ve observed are more cumbersome than they need be. There are plenty of hotkeys and mouse shortcuts to make the process go pretty quickly.
  4. More than 10 or so images can become quite demanding on machine resources.
  5. The complexity of your foreground will also affect the outcome. A clean, crisp separation between sky and land is preferable. Trees, poles, wires, and other things that extend through the sky are problematic.
  6. Lens distortion can also adversely affect the outcome.

Aligned Stacking Procedure

  1. Load all the photos as layers in Photoshop.
  2. Heal out airplane and satellite trails from each layer.
  3. Select all the layers and add to a group named “Sky
  4. Right click the Sky Group and duplicate the whole group as “Foreground”
  5. Select all the layers in Foreground.  Use Layer -> Smart Object -> Convert to Smart Object.
  6. Select Layer -> Smart Object -> Stack Mode -> Mean
  7. Duplicate Mean using Ctl-Alt-Shift-E (Command-Option-Shift-E on MAC). Label the newly created layer “Mean” and turn it off.
  8. Select all layers in Sky. Set blend mode to “Lighten” and observe the direction of star movement against the ground.
  9. Be sure the image with stars nearest the ground is at the BOTTOM of the stack. The bottom layer will be your base for alignment. You can drag layers around, or Layer -> Arrange -> Reverse may do the trick.
  10. Create a mask keeping as much of the sky as is easy to do but that DOESN’T include any ground  or fixed location objects. IMPORTANT: Be sure the mask doesn’t have holes in it, including at the bottom corners. Click the layer mask, hold down the Alt (Option) key and drag the mask to the next sky layer. Repeat until all sky images are masked with the same mask.
  11. Select the bottom layer and lock it  (Layers -> Lock Layers -> check Position -> Ok)
  12. Select all the sky layers.
  13. Chose Edit -> Auto Align Layers -> Auto
  14. When alignment is done, set blend mode for all sky layers to Darken. If stars are disappearing in the result image, that’s bad.
    1. If alignment is great everywhere, that is you have plenty of stars, you’re done. But it probably won’t be. So…
    2. Duplicate the current layers to a NEW document – call it whatever you want, but perhaps “Left looks good” makes sense.
    3. Open the history palette and click just above the “Align Layers” item (to restore to before the alignment was done). Lock the TOP layer (see item 11) and repeat steps 12-14.
    4. If a large portion of the image still has streaks in some quadrant, try undoing align, undoing the lock and re-aligning.
    5. If you’re still getting a significant amount of streaking you can also try Auto Align -> Reposition rather than auto.

      Q: Why do I have disappearing stars?
      A: The reason they are disappearing is because they are not aligned. In Darken mode, the darker sky “wins” out over the several stars. This COULD be a good thing in other situations, but not here!

      Q: If I went through the trouble of doing all this alignment, why is it still “off”?
      A: Photoshop isn’t optimized to align stars. Secondly, lens distortion makes a star move non-uniformly across the sensor. And third: stars at different declinations (celestial latitudes) travel at different speeds across the field. To eliminate streaks, the best solution is to track the sky.


  15. Take the aligned sky, delete all the layer masks. With all the aligned sky layers selected, create a smart Object.
  16. Do the same Stack Mode “Mean” trick for the sky smart object that you previously did for the foreground.
  17. The rest is pretty straight forward. Turn the foreground (mean) back on. Use a selection to reveal only the foreground and apply that to the Foreground Group.
  18. Adjust contrast, color balance, vibrance, etc. to your satisfaction.
  19. Save the kit and caboodle.

Does all this seem too complicated? Well, then perhaps you might consider using these tools instead. They do most of the hard work for you and they KNOW the difference between stars and foreground (usually because you help them know).

  • On a Mac: Starry Landscape Stacker – from the Mac App Store
  • On a PC: Sequator – do a Google Search to download it.

By the way there are many astro processing tools, like Deep Sky Stacker – but most/all of them expect that your images will have NO foreground or non-moving objects like wires in them.

Landscape Astrophotography

Thanks for attending my Landscape Astrophotography discourse with the San Jose Astronomical Association on Tuesday, June 19, 2018. 7:30 PM to 10:00 PM. Most of the audience are Astrophotographers.

Below is a form you can fill out and we will email you a PDF of the notes from this lecture.  Following are some brief excerpts from the talk.

The Meeting of Earth and Sky

Big Sur, California, has earned a reputation for being The Greatest Meeting of Land & Sea, a phrase attributed to Robinson Jeffers, the “Walt Whitman” of the West Coast. Indeed living here is inspiring. The towering cliffs and mountains, lush forests, crashing, craggy Pacific surf all work together to evoke a sense of beauty and wonder that is astonishingly intimate.  There are certainly other beautiful places in the world – even nearby. But I believe that there is awesome, virtually undiscovered beauty that touches nearly everywhere in the world: the night sky.

Night Sky photography has grown by leaps and bounds in the last decades. Prior to the age of digital photography, there were relatively few painters of the night sky. Not surprisingly, none of those painters painted just stars. All featured stars with landscapes. Perhaps the most well-known painter of the night is Vincent Van Gogh. In Van Gogh’s day, light pollution was far, far less noxious than it is now. Indeed our super abundance of artificial light has rendered our night sky almost unobservable. But the night sky has such depth and mystery that everyone should find a dark sky to sit under for a time. Part of the allure of the night sky is its expansiveness… its immense scale.

Because the scale of the night sky is difficult to grasp I believe it is important to link human-scale to the starry night. Deep-sky photography of nebula and galaxies reveals things completely unseen or unseeable by the naked eye – and the revelation of those objects is  compelling and engaging. But even more compelling are photographs that tie humanly identifiable scale to the mysterious night.

In addition to scale, compelling photographs reveal the unexpected. Photographs can show time, location, relationships, colors, and details that are unobservable by looking. To draw lay people, however, I believe there must be a strong link between what is observable with what is not: a Marriage of Earth and Sky. And for that reason, I’m urging Astrophotographers and astronomers to try Landscape Astrophotography.

As Numerous as the Grains of Sand

This is truly a meeting of Land, Sea and Sky

For more details, please see the accompanying notes.


Landscape Astrophotography Notes
Landscape Astrophotography Notes
71+ Pages of notes covering the following topics:
  1. How to Make Images Memorable
    • Scale / Grandeur
    • Connectedness
    • Interest
    • Revelation
  2. Impact of Photos
  3. How to Create Scale / Grandeur
  4. How to Connect - Interest and Familiarity
  5. Revelatory Photographs
    • Time | Location | Relationships | Familiarity | Seeing Differently | Surprising Colors | Intricate Detail
  6. Inspiration from Painting
  7. A sense of place
  8. An Astrophotography Idea
  9. Conclusion
  10. Resources and References





 

Other articles on this site that you may find relevant include:

Why Aim North?

Reaching for the Sky

Reaching for the Sky: 112 images, each f/4, ISO 800 for 60 seconds including a shot from twilight hour for the foreground Alabama Hills, Lone Pine, California

Want to capture Perseid meteors, the Milky Way, and star trails in an awesome location?

Join us for our>>> Field Event: Meteors, Milk Way in Alabama Hills <<<Sunday, August 12, 2018 (with an optional second night).  SORRY EVENT IS FULL

I live and travel in the Northern Hemisphere. In fact I have yet to travel south of the equator, so my apologies to those of you from the southern half of the planet for my obvious northern bias.  I believe those of you in the bottom half of the planet can just substitute the word South for North everywhere and everything should be correct.  I have added [parenthetical content for those who are in the southern hemisphere where that north/south swap doesn’t work]

The results obtained by shooting a long exposure at night depend quite a lot on which direction the camera is pointed. I favor long star exposures with a northern view for many reasons.

The Advantages of Shooting To the North

  1. Curvature of the star trails is strongest around the north star. Exposures of about 6 hours will appear to be full circles (24 hours of exposures are actually needed to make complete circles and that is not possible in one night except near the North Pole!).
  2. The moon will never intervene into the shot because the moon never passes through the northern sky.  [NOTE: those in the southern hemisphere still have to worry about a moon in their Southern shots]
  3. Cassiopeia and Ursa Major (the Big Dipper) are bright constellations that can always be found in the Northern Sky – so there is always some interesting sweep of stars possible. The region immediately around the North Star, however has dimmer stars which may only be captured through long exposures. [The southern hemisphere suffers for lack of many bright constellations near the southern celestial equator]
  4. With just a smidgen of star hopping skill it is easy to find the north star which, weather permitting, is always visible in the night sky.
  5. The moon sweeps east to west giving long shadows from the right or left of the subject. And when the moon is highest in the sky it can cast strong face light.
  6. The sun also never appears in the northern sky so it is safe to leave a camera running from before sundown to after sun up. Camera damage can result from a long exposure pointed at the sun.  [NOTE: those in the southern hemisphere still have to worry about a sun in their Southern shots]
  7. Since the moon cannot enter into a northern shot a photo can be made regardless of the moon’s phase and for as long as I choose. For shots toward the East, South or West it is important to know the moon phase and location during the hours of shooting to prevent problems from flare or washout. [NOTE: those in the southern hemisphere still have to worry about a moon in their Southern shots].
  8. The stars in the north move the slowest through the field of view which allows them to be brighter and reduces inter-exposure gaps in the trails.
  9. If I know my latitude I know how high to point the camera and be guaranteed to get a circle in the view.
  10. I do not need to know what constellations will be visible in the direction I will shoot.
  11. Two major meteor showers (the Perseids and Quadrantids) and 3 periodic meteor showers (the Giacobinids or Draconids, the Ursids and the Andromedids) are well placed in the northern sky.

The Disadvantages

There are a few detriments to pointing north, however:

  • Not every situation lends itself to a view from the south.
  • It takes a longer exposure to form a pleasing arc.
  • To get a circular arc, I must include at least 10 degrees or so above and below the North Star. The farther north you are, the higher in the sky the center of rotation. Those at more northerly latitudes will be more constrained in their choices.
  • The altitude (degrees above the horizon) of the north celestial pole may constrain the choice of lenses to very wide-angle – and may force you to use portrait mode. Or you can create your exposure by stitching together foreground and sky shots.

Another Northern View

Grand View [C_009613-686br]

Looking North from Grandview Campground, White Mountains, Bishop, California.  Shot at ISO 800, f/3.2 for 6 minutes each. Began at 10:11 PM and ended at 5:35 AM. That is 75 shots x 6 minutes = seven and a half hours. Grandview is at latitude 37 degrees North, so the center of the circular pattern is 37 degrees above the horizon.

What About OTHER Directions?

Southern View

Woosh

Woosh: 19 images. Each image: 6 minutes, ISO 800, f/3.2, Canon 5D Mark II, 16mm; Patriarch Grove, White Mountain, California

Eastern View

Valley of Stars (Remix) *Explored*

Western View

Stars and Stripes [5_065561-626li]
Granite Park - 53 Minutes (edited)

Notes

Contrary to popular belief, Polaris, the North Star, is not the brightest star in the sky. Sirius is the brightest star. The brightest objects in the night sky are the moon, and the planets Venus, Mars, Jupiter and Saturn. Also while Polaris is quite NEAR to the North Celestial Pole, it’s not exactly there so even Polaris will make a trail.

This is a reissue of an article originally written in October 11, 2010; Thoroughly revised and updated.

What Makes An Image Memorable?

Perhaps the highest praise Steven gets as a speaker is this:

Wow, his passion is infectious. I’m now eager to try night photography.”

Almost every photographer makes pictures to SHARE with others so praise of passion is high praise, indeed. Not everyone will have similar interests or feel the connection you feel with your work, but there are some questions you can ask yourself to strengthen the broader appeal of your work, that is, make your image more memorable.

My friend and mentor, Kip Evans sold his photography from a gallery in Carmel, California. One of his laments to me was: I don’t really sell what I find beautiful and compelling, I mostly sell what others have a connection to – often touristy things like images of the Golden Gate Bridge. What drew us into Kip’s gallery was an image of a large breaking wave called Winter Swell. We have print of Winter Swell hanging in our bedroom (and so does at least one coastal hotel).

        Kip Evans: Winter Swell

My wife loves waves – and I share her affinity. She will stand in awe and clap as huge surf crashes on to our coast. There is a visceral connection with the spectacle and power of the scene.

If we spend a little time thinking about what causes that kind of connection, we can endeavor to put elements of it in our work.


From my perspective, images need the following:

  • Scale that inspires awe, grandeur
  • Connectedness – intimacy in the viewer caused by an emotive reaction to the image
  • Interest – an alignment with the passions of the viewer – even if only tangential
  • Revelation – an innovative view that illuminates something either unnoticed or unseeable.

Of course these characteristics are inter-related and if only two of the four are strongly present that may be enough to wow the viewer.

Vote!

Before you move on to the explanations, consider the following 4 images. Decide which image is the one that best reveals scale, the one that speaks to you (connects with you), the one that is most in line with your interests, and the one that reveals something you’ve not seen or understood before. The answer to each question may be a different image. Indeed, we would love it if you’d answer the four questions in the polls below… If you want to elaborate or leave a comment listing your choices (e.g. “A,B,B,D”) that’s fine, too. And yes, we realize we have mixed in a photo of a cute dog that has nothing to do with Night Photography.

The images are
A: Sky from Orion to the Pleiades, B: Trona Pinnacles with Orion and Canis Major, C: Mount Whitney in Moonlight; D: Pierre Grazin’ in the Grass.

WHICH IMAGE:

... most shows Scale or Grandeur
... draws you the most?
... aligns with YOUR interests
... gives a unique/new insight

 

Revelation

Fortunately for Night Photography, the last part – Revelation – is the easiest. Few people have seen a truly dark sky with starry heavens. If you can connect the viewer by linking Earth and Heaven you can draw people in.  Even fewer people realize that the Milky Way is awesome, and that stars have discernible colors. It is not hard to enchant viewers with a revelatory image.

Revelation can take many forms, however. For example: showing an unfamiliar but interesting place, illustrating a relationship that was not obvious before, revealing unexpected or unobserved colors or details. The camera is very good at seeing color, even in dim light – so it’s almost easy to be revelatory in a night image. In my opinion the single most significant mistake that people make in night images is in not selecting or not providing sufficient interest in the foreground – either because the foreground is boring, or because it is not well enough illuminated to speak on its own. My personal bias is to tune out a photo of a car under the stars, for example, unless the car is really, really sexy looking. My wife, who is a car fan, feels a little differently. I am also not a fan of junkyard scenes with garish colors, but my judgments (biases) are not about revelation, but about Interest.

Perhaps one of the revelatory aspects of image D is the “on-eye-level-ness” with a furry little creature.

Photon Worshippers **Winner Astronomy Photographer of the Year, 2010 - People and Space **

Photon Worshippers **Winner Astronomy Photographer of the Year, 2010 – People and Space **

Interest

How many images of sunsets have you seen? Most of them are immediately emotive, colorful, and often compelling… but are they different enough to hold your interest?

People are all over the map in interests: favorite colors, past-times, subjects, hobbies … It is impossible to create an image that will be interesting to everyone. The point here is to think about your audience.  The photo that won Astronomy Photographer of the Year in 2010 (above) garnered interest because it was not a run-of-the-mill, same as everyone else night sky photo indeed it wasn’t a night sky photo at all! The image was something that I calculated would be of interest to judges in the UK. In the UK Stonehenge is an ancient, human-made edifice apparently built to measure seasons. My Photon Worshipper image is of a natural formation that does a similar thing – it only forms a beam of light during the winter solstice.  The image is also unlike the many existing images of the same phenomenon: it is a different view, and includes people to give it human scale.

Scale / Grandeur

Likewise my runner-up image in 2012 (below) was arguably the least well executed of my awarded work: focus is soft, color is off. But the scale and human interest of Lost In Yosemite is hard to miss. The contrast of tiny figures – once you recognize them as people – against towering trees and an immense sky was not lost on the judges.

I love this photo because it illustrates how humbling, even frightening, both the natural world and the cold depths of space can be for us as tiny, fragile human beings. ~ Olivia Johnson

Lost in Yosemite [C_033706] Runner Up - Astronomy Photographer of the Year, 2012

Lost in Yosemite: Two tiny hikers in flashlight against the enormity of the environment.

If you’ve seen it in person the scale of the Grand Canyon is inspiring. If you’ve seen it in photos, the Grand Canyon is LESS impressive. Why? My thought is that most photos lack human-scaled perspective of the kind in Lost in Yosemite above. Image A, above, is an image in which you likely found no sense of scale – unless you’re an astronomer. Image C shows rugged mountains (Mount Whitney, in fact). Hikers and mountaineers will implicitly understand the scale. Image B, however has formations that are of indeterminate size unless you have first-hand experience with them. Image D also gives scale clues… You see the size of the ears in proportion to the dog (named Pierre), and the size of the dog in proportion to the grass and flowers. But it’s not likely that it was the scale or size revelation of the dog that drew you in, is it?  If you found affinity with Pierre, it’s because you have – or had – a pet you are fond of, or wished that you had a pet. But we will address connectedness in a moment.

My suggestion is to be sure that something in your image imparts an easily recognizable scale.  In fact, putting a human in the shot can be powerful – Ben Canales won a National Geographic competition with an image featuring himself and Crater Lake – and a bit of whimsy.

Connectedness

Connectedness, or perhaps better term intimacy is not a single characteristic. By connectedness, I mean that involuntary emotive sense of drawing your attention – either as awwwww or that’s beautiful, or that’s disgusting, or my heart hurts. Sunsets, puppies, and kittens are perhaps the most photographed items of all. Why? Because most of them come laden with affection and fond memories – or sadness, or whimsy.  I immediately feel connectedness with well crafted night skies because I have many fond memories of sitting out in the dark under a horizon-to-horizon Milky Way.

I am reminded that compared to the enormity of the sky I feel small, but somehow embedded in that smallness is always a feeling of importance and one-ness with nature.

I assert that connectedness is usually a product of scale, revelation and interest, but connectedness can also occur spontaneously out of past experience and the human condition. My wife would put it this way:

Life is not measured by the breaths you take, but by the moments that take your breath away.

Technical Competency

I gave thought to avoiding discussion of this important aspect of an image. Some of my most viewed, appreciated and commented images are NOT images that exhibit technical mastery! I purposely chose images B and C because they are older work, and lack technical robustness. Indeed, I have much better images from Trona Pinnacles (Image B), but none have been as popular as image B!

In summary, while technical mastery is a great goal to seek, if you work too hard on making your image sharp, color balanced, and so on, you may neglect choosing environments and images that have more compelling characteristics: Scale, Interest, Connectedness and Revelation.

So What is My Favorite Image – And Why?

If you’ve been paying attention you’ll understand that images, like aromas, colors and words carry different weights due to our personal experiences. I always gravitate to the image below. It’s my wife on our last evening in Santorini, Greece.  We had just finished a fantastic meal, I had given her that ring, and our view was awesome. And, it happens to be a sunset I shot with my cell phone.

Last Evening in Santorini

You probably wanted to know what’s my favorite Night Image, though.  It’s hard to choose, but it’s probably one of these two. I’ve never uploaded the first one, though it’s predecessor was released.

“South Side,” Red Rock Canyon State Park, California

“Like Grains of Sand,” Pfeiffer State Beach, Big Sur, California

If you ask my wife the same question about my images, I am pretty sure she would pick this one:

Famous III [C_035478]

This is all part of a larger talk I am planning for a local Astronomy Club.  I appreciate your votes on the images above so I have a good set of data to go on. Also, please comment on an image that really inspired you – mine or anyone elses!