Category Archives: Image

Road Trip: Eastern Sierra, California

Do you know how to get permission” … is how it began.  And this question set in motion a two-and-a-half day trek with 16 hours (800 miles) of driving plus the usual sleepless nights.  The first night found us shivering at Mono Lake.  I knew it would be cold, but it was colder than I anticipated and my 7 layers of clothes were just barely keeping the frigidity at bay.  Unfortunately due to a low fog that crept in and the aforementioned bracing cold, we were unable to hang out until moonrise which that night was to be at 12:20 am.

Takeaway: Always be prepared for 20 degrees lower temperature than the forecast!

After sleeping in, and grabbing breakfast we took a long drive to Bishop by going through Benton and stopping at several Petroglyph sites.  There were some remarkable locations I’d never seen before along the route, including a place that looks strongly like the formations at Alabama Hills.  Unfortunately the photos I took with my Spyglass application were never saved… we’ll be talking about Spyglass in the future, so stay tuned.

Andy stares down #13

Andy stares down #13 as the sun sets.

The second evening we found ourselves at 7,200 feet elevation where clear skies turn a noticeable purple after sunset. But I talked Mr. Mean 🙂 into remaining until at least moonrise which on that night followed the rise of Sagittarius.

The Milky Way rises over the 10.4 meter radio telescopes at Cedar Flat, California.

The Milky Way rises over the 10.4 meter radio telescopes at Cedar Flat, California.

Here is a short timelapse from which the above is taken:

Awake All Night (PS CS6 version) from Steven Christenson

For a slightly different take including an additional sequence, see here.

The Route

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WIth Tioga pass closed, we traveled through Sonora Pass on the way out and by accident through Carson Pass on the way back.  There was precious little snow anywhere except in Carson Pass.  The area around Caples Lake was particularly nice.

Caples Lake, Ebbetts Pass, California. This is a little bay in the lake the lakes is MUCH larger.

Caples Lake, Ebbetts Pass, California. This is a little bay in the lake. Caples Lakes is MUCH larger.

The shoreline of Mono Lake with a large Tufa formation and stars of the North Western skies.

The shoreline of Mono Lake with a large Tufa formation and stars of the north western skies.

By the way, I’ve referred to Andy as Mr. Mean only because he was insistent that I not pay for the gasoline for this long trip.  I don’t think he really has a mean bone in his body. Meanwhile, you might want to check out his antics on his blog: PhotoshopScaresMe.com

Star Trail Creation – Step By Step

Originally Published: November 19, 2012
Last Revised: March 3, 2017

I dredged this one up out of the archives. Many people ask me “how do you do those star trails, Steven.”  If you want a grand overview of the process, my Treatise on Star Trails is a good read. However here I reveal step-by-step how I create a star trail image from the first shots to the finished image. The method shown below is for creating simple (lighten mode) star trails. If you want to do some fancy effects, please take a look at our Advanced Stacker Plus.

Here we go.

South Side [C_009842-75br]

Photo 1: Quickly stacked image which is a composite of thirty-three 6-minute 500 ISO exposures and one 30 second, ISO 2000 exposure.

The above is my first quick attempt at creating a star trail, and following is summary of how I created it.

It starts with the test image and continues with the exposure set. For background on how to navigate the various shooting choices, see: the summary Stacker’s Checklist. The theory about selecting exposures may help.  And there is a two-part series that addresses the difficulties you may encounter. See Part 1 and Part 2. If you’re curious how I get the stars to form circles, this article will provide the information.

I usually start with a short (30 second or less), high ISO exposure to gauge several things: 1. How well framed my subject is, 2. How sharp the focus is, and 3. What I may need to adjust to control the sky-glow.

Photo 2: First, image: ISO 2000, f/2.8, 30 seconds.

After taking the first image, I realized two things: one is that the trucks passing were providing helpful light on my foreground – but not always illuminating the entire thing.  The other is that the exposure (ISO 2000, f/2.8, 30 seconds) was under exposed.  I needed to at least double the exposure to 1 minute. Let me stop for a moment. Those of you who don’t do much night photography are thinking “Whoa from 30 seconds to 1 minute is a huge difference.”  But no, it’s not. It’s only one f-stop. It is no different from changing a daylight exposure from 1/200 of a second to 1/100 of a second.

Starting with an exposure at 1 minute, 2000 ISO f/2.8 as a starting point I calculated an  ISO 500, 6 minute exposures at f/3.5. Here is how: A 1 minute exposure at ISO 2000 is equivalent to a 4 minute exposure at ISO 500 (500 is 1/4 of 2000).  Changing the aperture from f/2.8 to f/3.5 drops the light by about 33%, so I increased the exposure from 4 to 6 minutes.

I set my camera to record in RAW and my interval timer to take 5 minute, 59 second exposures every 6 minutes. I pulled out my reclining beach chair, a sleeping bag and slept while the camera clicked.  Below are a few of the shots. Note how the light changes from passing trucks!  You can also see the counter-clockwise rotation of the Milky Way. The last shot was taken as twilight approached is too bright to use because the sky is losing contrast and the light on the cliff is looking flat. I did not include that last shot in the stack.

Photo 3: Collage of some of the photos used in the stack.

I downloaded all the images from my card to my Incoming folder which is organized by date.  I used Digital Photo Professional to pull up the images, applied a bit of contrast enhancement, a slight exposure increase (1/3 of an f-stop), and a very slight noise control over the entire image. I exported in Landscape style which adds a slight saturation increase (Photoshop Saturation and Vividness) and modest sharpening. I cloned the recipe to all the photos and exported them into a “RedRockEast” folder in a temporary directory.  I could have done all these things with ACR (Adobe Camera Raw) or Lightroom.  In this case I didn’t have to do any white balance adjustments because I had preset the camera to approximately 4100K.

I then dragged and dropped all the exported (JPG) images onto Image Stacker which took about 3 seconds per image – less than two minutes to create a result. My option for Image Stacker was “Brighten” mode. I could have used the Star Circle Academy Stacking Action in Photoshop instead and the result would have been identical.  The stacking action takes about the same amount of time, but is more versatile and can even use raw images. (Note: StarStax is a program that supports Mac, Unix and Windows and works well, too!)

Photo 4: First Results stacking 34 images in Image Stacker by Tawbaware – this is effectively a 3 hour, 24 minute exposure.

The result was a little dark and flat so I used Picasa 3 to increase the exposure (called Fill Light), highlights and shadows – each by about 1/4 of the scale, and I warmed the photo by slightly tweaking the white balance (Color Temperature). That was all I needed to get the image shown in Photo 1.

Screen Shot 1: Picasa Adjustments

One obvious problem with the result is that the combination of the early short exposure with the sequence of shots left a gap. There really was no reason to include the first shot.

I want the cliff to pop a bit better, so my next course of action was to work on improving the foreground.  I found all the brightest shots of the cliff face (e.g. when the trucks were lighting them), and combined them using additive stacking to brighten them and averaging to reduce the noise. Remember that “brighten mode” (Lighten in Photoshop) does not brighten anything – what it actually does is select the brightest pixels at each location from each of the images in the stack.  The brightest pixels may also be noise! Using averaging reduces the noise significantly – but it will not remove “hot” pixels; we will address those later.  Fortunately Image Stacker has an option to stack and average. All you need do is specify the divisor.  If you have 10 images and specify a divisor of 10 then you are simply averaging. But if you specify a divisor of, say 5, then you are averaging AND effectively increasing the brightness by about 1 stop.  I used 12 images and a divisor of 3. And I made the same adjustment to the result in Picasa as I showed in Screen Shot 1. But I wasn’t happy with the result – the foreground still wasn’t bright enough.

Next I took 10 of the brightest images and Stacked them (additive).  After tweaking shadows and brightness in Picasa I got this:

Photo 4: Additive stack of 10 images.

Now my foreground is better, but I have created a new problem. The sky is over-bright and the hot pixels and the noise are significant as shown in a 100% crop below.

Screen Shot 2: 100% view showing Hot Pixels and noise (white speckles)

The hot pixels here have a purple fringe to them. Sometimes hot pixels are tinged red, green, blue, white or gray. I will fix hot pixels in my next to last step using the clone stamp (Picasa’s retouch) or the healing brush in Photoshop.

While the noise is obvious at 100% I think it will be fine so I am not going to address it.  If I later find the noise intolerable I will go back and stack more images and average them. Or I may return to the original images and apply stronger noise reduction in Digital Photo Professional and re-export them.

My next task is to remove the over-bright sky from the Photo 4, above. Sky removal is rather easy with the wand selection tool in Photoshop. I select all the sky and fill with black after making a few more tweaks to contrast and color.

Photo 5: Sky removed and replaced with black.

Since I now have a black sky version with the foreground as I like it, I can include this frame in any other stacks I make, and my foreground will be just as I want it. If I were working entirely in Photoshop, I would not have to fill with black, I could just use the result as a layer with only the foreground revealed by a mask.

To complete the process, I restacked 33 images together with the sky-less foreground image (Photo 5). Some more minor shadow and color temperature tweaks and some spot corrections of the few hot pixels (there were about 15), an addition of my copyright and this is the result:

Photo 6: Final Image

Since I had all the images for the stack, I was challenged on Flickr to also make a time-lapse video. This video below also helps to illustrate how stacking works. I collected the original thirty-three 6 minute exposures and cropped them to HD format (1920 x 1080). I then created and a sequence of stacked images using the intermediates option of Star Circle Academy Stacking action and joined them into an animation complete with a lovely snippet of the song Kidstuff by Acoustic Alchemy. In my next column, I’ll show how to create the time-lapse animation.

Red Rock Dancing *Explored 03-03-2011*

If you would like hands on experience and instruction, you can join us at a StarCircleAcademy Workshop

Meteor Hunting

I thought the evening was a disaster. I got to bed at 10 pm. Set the alarm for midnight. Got up and saw that the clouds were impenetrable at my home near Los Gatos, California. With a sigh I finished packing up my equipment and set out toward the place I had picked days before.  It was a private home with an open lot and a great view of the Diablo Mountain Range.  The owners had agreed to let me arrive at midnight and remain until about 5 am. BUT when I arrived I couldn’t see the stars or the mountains. Darn.

I know that sometimes the mountains east of the San Francisco Bay Area block the low clouds from advancing inland, so I continued on. Sure enough I noticed from the freeway that I could actually see a huge hole in the sky. Astronomers call them “sucker holes” because they sucker you in to thinking its worth setting up equipment.  I had to find a way to turn around on the freeway and find an off-freeway road with a decent view.  Finding such a place took about 20 minutes, and by the time I arrived, thick clouds had enveloped the eastern sky, but at least I could sometimes make out stars to the north, including the all important Polaris.

I set up and aligned my Polarie, and started the automatic timer to take continuous 44 second exposures (2000 ISO) starting at 1:28 AM. I figured, the clouds were sometimes thin enough that I might capture a meteor through them – after all, once in a while I could make out where the bright planet Jupiter was.  Time passed and I huddled in my car with what seemed like 20 layers of clothes. I had forgotten my pillow and my sleeping bag and didn’t have my customary thermos of hot chai. The night was cold, breezy and a little damp so the shelter of the car was essential.  I slept fitfully. Each time I awoke I saw thick clouds. From 2:16 to 2:23 the clouds seemed like they were going to disappear but they were just teasing me! I slept and shivered some more. I finally found my emergency coat – a tattered old garment I keep in the car which my wife would never willingly let me be seen in public with,  and a towel to use as a blanket on my legs. By 3:56 AM the Polarie had tracked Orion high into the sky so little of the foreground was left in the shot. But now the sky was dramatically clearer! Thick clouds threatened in the west but my view of the sky was much better.

I moved the camera and reoriented it vertically so I could keep the slope of the hillside in the shot for at least a while. I watched for a bit hearing the familiar sounds of the shutter closing, pausing, opening…  A brilliant meteor appeared – it was definitely in my field of view! I was almost ecstatic until I noticed the sound of the shutter opening again and realized the bright one had appeared and left while the camera was between shots. It got away! I later discovered that I did catch one little meteor in the vertical mode (see above).

From 4:16 to 4:55 I let the rig continue running in the vertical alignment and retreated again to my car for warmth. But now Orion was heading farther and farther south where the fierce light pollution from Fremont and San José was daunting. I aborted the vertical shot and framed up a lovely spreading oak tree that caught my eye. I spent a solid 15 minutes on that oak tree with Orion hanging above it.

It was now 5:03 in the morning and I was colder than ever.  So I decided I’d reframe the sky shot to avoid the glow of the cities and retreat to the car out of the wind. It was then that I finally really slept and I woke when my alarm went off: 6:02 AM.  I was leading a group of hikers to scrub graffiti off the summit of Mission Peak and some were going to meet for breakfast at 6:30 AM.  The sky was mostly cloudy again, but I spent a few more minutes framing up my friend the oak, collected my equipment and headed for Denny’s.  I spent the rest of the morning and afternoon with a wire brush and paint remover.

After my graffiti scrubbing expedition I was exhausted and slept until early Saturday evening. I copied and started looking through my images. I found a very peculiar one almost right away.  I wondered what the “squiggle” was.

Looking at the frame before the squiggle was still there, though the shape was different.  I kept going backward until I found a brilliant flash. BINGO! It seems the meteor appeared at almost exactly the time that my alarm went off. I never saw it with my tired eyes.

I hastily grabbed the frames from just before the meteor until the floating squiggle ceased to be visible and assembled them into a timelapse:

And there you have it. Almost 5 hours of clouds, a very few meteors and one of the most fascinating phenomenon I’ve ever captured.

By the way, I now have literally thousands of shots to sort through from the following night which was much clearer. So far no brilliant streaks. 🙁

If you’re wondering what settings and tricks to use to capture a meteor, please see my article.

If You Want a Better Star Trail…

When I went the Department of Motor Vehicles in Raleigh, North Carolina there was a sign next to the camera that was a bit harsh for the genteel south, especially if you did not have much of a sense of humor.  The sign read:

If you want a better picture bring a better face.”

I doubt the sign is still there, but the thought is more profound than it may seem at first blush. Beware because you are about to read something that might disturb you just as the DMV sign caused some people to sneer while others, like me laughed.

Brother's StarburdenPictures of star trails (like the one at left) are BORING. Ho Hum. Yes, taking star trail photos is technically a bit challenging. And it is also interesting – for a short while – to the photographer and even friends of the photographer. But really, what do you have? White, and sometimes colored lines across a frame. It’s the KNOWING that those are stars and the photo represents time that starts the mind in motion.

I may form a strong emotional connection to a photo of my cat  but that does not mean it’s a good picture. It means I have a strong bond to MY cat. Something compelling and visual must be present for my cat photo to be interesting to someone else.  (PS I don’t have a cat – my wife is allergic to them).

(son of) Bristlecone Pine Star CircleTo me, a star trail must attach earth and sky, tell a story, suggest something of wonder or awe or longing.  That is why for the better part of 2 years I’ve been collecting star trails in a gallery on Flickr called “The Best of Star Trails.” I am the primary judge of what makes it in to the photo pool so the photos reflect my opinion. But if you look through those photos you should notice something. Actually two things.

  1. Almost every image has more than lines in the sky – there is also light on something in the foreground.
  2. Most of the images would be interesting even if there were no stars or star trails at all.

I have never set out to capture a star trail where the sole goal was a star trail. I always attempt to marry an interesting foreground with the sky.  The more interesting the foreground, the more interesting the photo, at least that’s the way I see it.

Moon Break - Restacked...

Here are a few more tips – your mileage may vary:

  • Don’t “center” the circle of a circular star trail. Leave it off to the left or right to strengthen an image (e.g. like the rule of thirds).
  • Leave some breathing space around the center point.  This usually means super wide angle lens unless you are shooting at a low latitude.
  • It doesn’t have to be a circular star trail to be interesting!
  • The moon can be your friend.
Foreground Revisionism [B_02555-714br]

Mauna Kea, Hawaii, moonlit, 7 hours of exposures.

What about you? What makes a star trail shot interesting to you?  Please comment, we’d love to hear from you.

South Side [C_009842-75br]

Red Rock Canyon State Park, California. The star trails are dense because a very high ISO was used.