Comprehensive Guide For Photographing Star Trails

Some people consider star trail images to be cliché, but I happen to like well-done clichés. I don’t know what it is, but something about those light streaks captures my attention more than most night subjects. But while it’s ridiculously simple to make a star-trail photo, it’s not so easy to make a good one. It takes a lot of planning and execution.

In an earlier three-part series, I discussed some of the more technical details about star trails. Part One dealt with the shape of the lines, Part Two talked about the length of the trails, and Part Three discussed the color and intensity of the trails. This article is designed to be a comprehensive guide for getting you started shooting star trails or brushing you up if you’re already shooting them. I know there are still a few film shooters out there and while this guide is for the digital photographer, you’ll find that much of it applies for you as well.

Star Trails at PARI radio telescope

Star trails and the 26-meter radio telescope at Pisgah Astronomical Research Institute in North Carolina.

With pinpoint star scenes, we’re trying to create an image that replicates what we see in the sky at night. With star trails, on the other hand, the resulting image looks nothing like what we see, but is instead a representation of Earth’s rotation. The idea is to set up the camera on a fixed tripod and open the shutter long enough to allow Earth’s rotation to cause the stars to record as streaks of light.

If you’re having trouble grasping how star trails work, just imagine the stars as fixed points of light in the sky. For all practical purposes they do not move. But Earth does move (rotates), so if you mount a camera on a tripod and shoot a long exposure, the stars record as streaks. It’s the same thing as photographing fireworks or any other streak of light, but in reverse. With fireworks, the camera remains still while the light streak moves. With star trails, the light source remains still while the camera moves under it. Both scenarios result in the light recording as streaks.

So the concept is simple. Mount the camera to a tripod, point it at the sky, open the shutter for two or three hours, and you got a star trail photo. Simple, right? Yep, except for the part about it being simple. Actually, it is simple to make a star trail photo. But as I said, making a good one requires some work.

The first consideration is that you can’t shoot a two- or three-hour exposure. Well, you could, but the resulting image would show nothing but noise. Back in the film days, we could load an ISO (ASA) 100 film in a camera and open the shutter for a few hours, never worrying about how noisy the image would be. Try that with digital and you’ll be hitting the delete button when you’re finished. If it’s very cold outside (heat contributes to noise) and your camera has good noise characteristics, you might be able to get by with a 30-minute or even longer exposure as long as you shoot at a low ISO. But if you want a relatively noise-free image, or one with long star streaks, you’re going to have to shoot multiple exposures and stack them. Don’t let that scare you; it’s really not that difficult. Read on…

The Concept of Multiple Exposures

Don’t panic! Even if you don’t do any post processing of your images, you can do this. Trust me. I’ll be going into a lot more detail about stacking layers later on in this article, but for now, I want to explain the basic concept. As stated above, with star trails, it’s very hard to shoot a single exposure with digital because of excessive noise. So we shoot a lot of shorter exposures and stack them as layers. This gives us the accumulative effect of the star streaks, while exhibiting only the noise from a single exposure. It’s magic!

But there are other advantages as well. One is that we can also shoot multiple exposures for the foreground and stack those in with the star trails. And here’s the biggie: We don’t have to shoot the foreground in the same exposures with the trails. So we can set up a campsite scene, for instance, and shoot all the exposures we need to get the campfire and tent lighting just right, and then shoot our star trails. Then we stack everything together to create the finished image.

There’s a little catch, though. (There had to be, right?) While you can very easily stack your star trail exposures using free software (more on that later), if you also want to stack foreground layers that you shot separately from the star trails, you’ll have to use a software such as Photoshop that has layer capability. And you’ll need to learn at least the basics of masking with layers. Fortunately, there is an overwhelming amount of information on the Internet to help you with this.

Steel Wool Light Painting-Star Trails

I did the steel wool light painting on a separate exposure from the star-trail captures. Notice how some of the light streaks that are in front of the sky are hidden. That's because the sky is lighter than the steel-wool streaks and the Lighten Blend Mode I used to blend all the layers only shows the lightest part of each frame.

Lots more to come about layers. For now, just keep in mind that by shooting multiple exposures and stacking them, you have a lot more flexibility with the foreground lighting, regardless of how much post-processing you do.

For those of you who just don’t want anything to do with layers and the post-processing side of this, you can get by without shooting the foreground separately. You can simply do any light painting desired during the same exposures you make for the star trails. The disadvantage of this should be obvious, and that is that you have no margin for error in you light-painting exposures. Whatever you do is going to show up in the finished image.

Gear list

  • Camera
  • Lens
  • Tripod
  • Intervalometer
  • Lens warmer
  • Camera power
  • Memory card
  • Miscellaneous goodies

Camera. Most cameras work fine for star trails. The camera must allow you to set the aperture, ISO, and shutter speed manually and the shutter must have a “bulb” setting that lets it remain open for as long as you choose. The only other requirement is that it accepts an external programmable shutter release (intervalometer) that plugs into the camera.

Lens. You can use everything from wide-angle to extreme telephoto lenses for star trails, but you’ll use wide angles the most. See the section on composition for more about this.

Tripod. Unless you have the ability to handhold a 2-hour exposure rock-steady, you’re going to need a tripod. A sturdy tripod. You’re going to be leaving the camera set up for hours at a time. Regardless of how calm the wind is when you begin, a sudden gust could topple a flimsy tripod. A strong heavy tripod is also good insurance against accidental bumping from a night photographer’s bumbling feet. Don’t laugh; you wouldn’t believe how many times I’ve bumped my tripod when shooting at night.

Intervalometer. You need the ability to program the camera for shooting continuous exposures up to several minutes long. Many cameras have programmable timers built into the menu system, but as far as I know, none of them will allow shutter speeds longer than 30 seconds. For Nikon shooters with cameras having a 10-pin port, you want the MC-36A or one of the much cheaper knockoffs. For Canon shooters, it’s the TC-80N3.

Lens warmer. Yes, I said LENS WARMER! If you’ve shot many star trails or nighttime time lapses, you’ve undoubtedly experience the problem of dew or frost forming on your lens. It’s an unfortunate fact of a night photographer’s life. There are several methods for combatting dew, but only two of them really get the job done and only one of them is practical for any shooting scenario. If you’re shooting close to the car, you can use battery-powered heater strips that wrap around the lens and keep it warmed above the dew point. In my opinion, the most practical solution is to use hand warmer packs to heat the lens. I invented the LensMuff™ just for this purpose. This article explains in detail all of the methods of dealing with dew.

Camera power. For most of us, this is not the issue that as it used to be. When I was shooting star trails with my Nikon D200 and then the D700, I was lucky to get two hours on a single battery charge. I had an electrical engineer friend make a special adapter that allowed me to power the camera using a 12-volt battery so I could go as long as I wanted. Now that I use the Nikon D800, I have no need for external power. On a single D800 battery charge, I can go nearly four hours, which is plenty long enough for star trails.

I recommend that you test your battery to see how long it will last for a star-trail sequence. First, make sure it is fully charged. Then set the camera to shoot continuous four-minute exposures, which is a typical shutter speed for star trails. You’ll need the programmable timer for this. Make sure you test all of your batteries, as they probably won’t all be the same unless they’re brand new. And don’t do the test by simply opening the shutter on bulb and leaving it open until the battery dies. For the test to be accurate, it must duplicate the operations of a star-trail capture, which involves closing the shutter after each shot, writing to the memory card, and opening the shutter for the next one.

Campsite with Tent and Star Trails-Camper Drinking Wine

This is a self-portrait setup shot in my backyard. The tent lighting comes from a flash pop with a yellow gel filter attached. I'm controlling the flash with a radio remote trigger. The beverage is red wine, of course!

Once you know how long the battery will power the camera, it’s a good idea to write the time on the battery using a Sharpie pen. That way, you can pick the strongest battery you have and you’ll know just how long it will last for each outing. And since batteries lose capacity over time, you should test them every six months or so.

If your camera battery won’t power the camera long enough to give you the length of trails you want, you have two options. Maybe. For some cameras, there may be other power options offered by the manufacturer or third parties that will give you more juice. The options are so varied that I’ve stopped trying to keep up with it all. You’ll just need to do some research for your camera.

The second option isn’t something I recommend, and that is to switch out batteries during the star trail capture. Even if you’re really fast, it’s going to take at least three or four seconds to turn off the camera and intervalometer, switch batteries, and then turn the camera and intervalometer back on. And you have to turn the camera and intervalometer off before you switch out the batteries or you could screw up their minds. (They are computers, after all.) A three-second gap between star trails is going to show up in the photo and the gap-filling technique I discuss later on won’t help.

Memory card. I’m often asked if you need a fast memory card for shooting star trails, so that the camera can write all those exposure to the card quickly enough. Actually, it’s even less of an issue than in other types of photography. The camera only needs to write one exposure to the card between exposures of at least 30 seconds. If a memory card couldn’t handle that, you wouldn’t be able to take pictures of anything and there would be no need for a camera to have the ability to shoot multiple frames per second. For star trails and most time lapses, the internal buffer in your camera is more than enough for even the slowest memory card.

Miscellaneous goodies. As with any night photo, there are lots of other types of gear you might utilize in the shoot. Light painting gear, alarm clocks, warm clothing, flashlights for focusing on foregrounds, black cloths for shooting dark frames (more on that later). headlamps or Night Vision Hats for setting your gear in the dark, etc., etc. But the items listed above are the only ones you have to have. (Okay, you could get by without an interval timer, but with most cameras the longest shutter speed you can shoot is 30 seconds and the maximum number of exposures you can shoot continuously is 100. And you could get by without a lens warmer, but if dew forms on the lens, the photo is ruined.)


The positions of the stars will vary depending on the direction and time of year you shoot, but once they streak into star trails, they pretty much all look the same. A photo that shows nothing but star trails might look cool at first glance, but it will quickly become boring. You need something beside the star trails for the image to be successful. The elements you include in the foreground will determine the image’s success more than anything else.

Foregrounds can be a silhouettes or lighted objects, or combinations of both. Graphic objects that project in the sky work well as silhouettes—trees, lighthouse, bridges, interesting rooflines, and towers are good choices. For a lighted foreground, almost anything is a good candidate. I like to use campsite scenes, waterfalls, and old barns and cabins.

The foreground and its lighting determine how much of the sky you include in the composition. If it’s a distant mountain range for instance, without anything lighted in the foreground, you’ll probably want to compose so that only a narrow line of the mountains are at the bottom, with star trails taking up most of the frame. You don’t want a big blob of black nothingness occupying a large portion of the composition. If, on the other hand, you are light painting an object in the foreground, you can include less sky and more foreground.

Star trails make very strong compositional elements, so you don’t need to fill the frame with them for a successful image. Compose the scene as you normally would and let the star trails fall as they may. An exception to this is when you want circular trails, as discussed below.

Ideally, you’ll want to set up the composition before it gets dark so you can make sure everything is fine-tuned and in focus. If you do this, be sure to pay attention to the elements that you won’t be light painting and make sure any black areas will complement the scene rather than detract from it. Remember, a little black can be a good thing. A big blob of black nothingness…not so much.

The Shape of Star Trails

I talked in detail about the shape of star trails in this article. Star trails look different according to the direction in the sky in which you shoot. It’s all very interesting stuff (to me, anyway) but it’s not something you really need to think about when deciding on the composition. The exception is with circular trails. When you point the camera toward the north or south celestial poles, star trails record as circles around the pole. It’s a dramatic effect, especially if you choose the foreground subject with this effect in mind.

Star trails at lighthouse

Star trails encircle Polaris behind the a lighthouse on Cape Hatteras National Seashore. I was careful to compose the scene so that Polaris was directly behind the lighthouse light.

Most of you reading this live in the Northern Hemisphere, so your circular star trails will revolve around Polaris, the North Star. Do yourself a favor and learn how to locate Polaris and use it when you compose your photos. Its position in the sky varies according to latitude. The farther south you are, the lower in the sky it will appear. If you stand on the North Pole, it lies directly overhead.

Star trails circling Polaris look really cool, but ANY well-executed star trail looks good, so you shouldn’t get upset if you aren’t able to point north. Choose composition based on the foreground elements.


I probably get more questions about focusing in the dark than any other subject. (Well, except for, “What camera do you use?”) This article goes into a lot of detail about focusing, so I won’t belabor the subject here. If the foreground is far enough away, you can get by with focusing on infinity. Autofocus on a bright star, planet, distant street light, or use Live View. With a close foreground, you’ll want to focus closer to the hyperfocal distance, which will give you the most depth of field from near to far.

With star trails, you’ll be shooting mostly wide-open apertures of f/2.8 or f/4, but with a wide-angle lens you still have a tremendous amount of depth of field. For instance, with a 24mm lens at f/2.8, you have full DOF from roughly 13 feet to infinity when focused at the hyperfocal point of 25 feet. With the 14mm lens that I often use, DOF ranges from an incredible 5 feet to infinity at f/2.8! You can find and print DOF charts online, or use any number of apps. I use an app called TrueDoF.

In all honesty, you don’t have to go to a lot of trouble figuring out hyperfocal distance. As long as you use a 24mm or wider lens and make sure the foreground is at least 25 feet away, you can safely focus on the foreground and be safe at f/2.8

But how do you see to focus in the dark? Good question. First, let me say that I use autofocus for nearly everything. My eyes are just too poor to focus manually, and the distance scales—including infinity—on a lens are simply not accurate enough. But I have no trouble using autofocus on 99% of my night subjects. The article I linked to above goes into more detail, but I’ll explain my technique briefly here.

The first option is to shine a flashlight onto the foreground so that autofocus will work. If that doesn’t work, simply carry the flashlight to the same distance as the foreground subject (or the point where you wish to focus) and lay it on the ground, pointing back at the camera. Then walk back to the camera and autofocus on the light. You can also use a powerful laser pointer to project a dot onto something and focus on that, but I find I don’t need to that very often. Remember, you don’t have to focus on something that is in the composition. The only thing that matters is that the object you focus on is at the desired focusing distance away.

Of course, the best option of all is to set up the composition and focus before it gets dark. I do this whenever I can, even if it means I have to sit around and wait before I can start shooting.

Regardless of how you get the focus set, it is critically important that you turn autofocus off afterward. If you don’t, and depending on how you have the camera set up, the camera may not fire because it will try to focus again when you press the shutter to shoot. Another critical step is to tape the focus ring on the lens so gremlins don’t move it once you start shooting. Trust me, no matter how careful you are, you’ll accidently turn that ring at some point. Make sure you use gaffers or painters tape, so you don’t leave a gummy residue on the lens. The lens I use for star trails is an internal focus lens, which means the lens barrel does not rotate when it focuses. Since I use autofocus for everything, I keep the focus barrel taped down at all times. I just switch out the tape every few weeks so it doesn’t become too stuck.

There is one way to shoot with a very close foreground and still get them both in focus, even when shooting wide open. Focus on the foreground and shoot it first, then refocus on the sky and shoot the trails. You’re going to be stacking multiple exposures anyway, so it doesn’t matter that you change focus between foreground and sky. However, the type of foreground does matter when using this technique. It works best when the foreground you are focusing on has some separation between it and the sky, such as distant tree line or mountain range, or just some black nothingness. The focus on the trees or mountains goes with the focus on the stars, so their edges look sharp. If the foreground object has edges that blend with the sky, you could have problems. An example would be shooting through a window so that the window frame creates a border around the sky. When you refocus on the sky, the window will get blurry and this will show up on all of the star trail exposures. An easy way to prevent problems with this technique is to make sure that the foreground object you are focusing on separately does not project into the sky.


There are two considerations here: Exposure for the foreground and exposure for the star trails. As explained later on, it’s important to understand that you can—probably should—use different exposure settings for each.

Exposure for the Foreground

The settings you use for the star trails have some roughly fixed parameters and as a result will be pretty much the same with each shot, but not so for the foreground. There are so many variables you’re just going to have to figure out this one for yourself. Keep in mind that since the foreground will usually be stacked with the star trails as an entirely separate entity, you can use whatever aperture, ISO, and shutter speed settings you like.

Icicles and Star Trails

The light painting on the icicles comes from passing cars during the star-trail captures. This worked out to my benefit, since the icicles merge with the star trails. If I had light painted the foreground separately, it would have been very difficult to blend it with the star trails.

With this in mind, you’ll want to choose the settings that give you the best image quality, while still providing adequate exposure. Generally, this means the lowest ISO possible in order to minimize noise, an aperture that gives you adequate depth of field, and a shutter speed that is a short as possible, also to minimize the noise.

Don’t forget that you can shoot as many exposures for the foreground as you like. For instance, if you find that you can’t do a good job with the light painting without shooting a very long shutter speed, you can break up the painting into several shorter exposures. That’s how I do most of my light paintings.

There is a very important consideration regarding light painting a foreground for a night-sky scene. If the object you light paint projects in to the sky, you could have some problems when you stack the exposures. The reason is that before you can stack a light-painted foreground layer, you have to brush out the sky (use a black brush in Photoshop to paint over the stars) so that the stars from that layer don’t show up on the finished image. If the exposure you used for the foreground light painting is enough to cause the sky to be very bright, it’s going to be very difficult to selectively brush out the sky, particularly if you have something like trees in the images. You want to make sure that the sky in the foreground exposure is darker than what the sky will be in the star-trail exposures, so it won’t interfere when you stack the layers. If the object you’re light painting doesn’t project into the sky, you don’t have any problems because you can simply brush out everything but the object you painted.

I always use a different battery for the foreground light painting than the one used for the star trails. For the trails, I want a fully charged battery so I can get as many exposures as possible.

Exposure for the Star Trails

Read this article for a more detailed discussion about star trail exposure, although I’m including most of the relevant information from that article here.

For star trails, the most important exposure consideration when making the photo is ISO. High ISOs tend to wash out the color because they are essentially causing over exposure in the stars. Aperture plays a role, too, but it isn’t as important. I shoot all star trails and pinpoint star scenes at mostly wide-open apertures because, as a rule, I’m trying to bring in as much light as possible in the shortest amount of time. But, of course, at a certain point, too much light comes in and washes out the stars. You could adjust this with the aperture, by stopping the lens down, but with all else being equal, it’s much better to lower the ISO first because lower ISOs give you better image quality, with less noise.

Think about what happens when you shoot a star trail. Earth is in constant motion, so the instant you open the shutter, the star begins to streak. The shutter speed at which that streaking becomes obvious in the photo is the subject for another post. For now, just remember that the star is constantly moving across the frame. For it to record at all, the aperture and ISO combination must capture enough of its light before it moves on to the next pixel. If you keep the aperture as a constant, say f/2.8 or f/4—a typical setting for stars—the ISO will determine how much of the star’s light will record.

If the star is very bright to begin with, it won’t take much for it to record even at low ISOs of 100 or 200. (We old farts used to shoot star trails using Fujichrome Velvia film. That’s a film speed of 50!) Two things happen as you crank the ISO higher. One is that the star trail appears brighter. The other is that faint stars—those that might not record with lower ISOs—will show up in the image.

Pondering this, you might wonder why you wouldn’t want to crank that ISO on up to 3200 or even 6400 or higher so you can capture as many stars as possible and have them appear as bright as they can. Yes, you’ll get lots of stars—bright stars—if you do that, but they won’t have much color because they’ll be overexposed. Overexpose anything, even a black subject, and the color goes away. With stars, it doesn’t take much for that to happen. Oh, you’ll also get a bunch of noise with high ISOs, even with short shutter speeds.

Notice that I didn’t say anything about the effect of shutter speed. That’s because there isn’t any. It’s true, shutter speed has no affect whatsoever in the exposure of star trails. Aperture and ISO control the exposure exclusively. Shutter speed only affects how long the star trails will be, not how bright they will be. That’s because the stars are moving. They never occupy the same pixel space long enough for shutter speed (beyond a certain point) to have an appreciable effect on the exposure. Shutter speed does affect the exposure of the background sky, so you do have to take that into consideration.

There’s another consideration with high ISOs and star trails. I said that as you crank up the ISO, faint stars begin to appear. The higher you go, the more stars you’ll record. Seems like that would be a good thing as long as you can retain the color in them, right? Well, that’s up to you.

Night Waterfall-Star Trails-Light Painting

Nikon D800 and Nikon 14-24mm lens. For the star trails, I shot 52 frames at ISO 200, f/3.5, and a shutter speed of 4 minutes. For the waterfall, I shot separate frames and light painted the water with an LED flashlight and a blue gel filter. For the trees, I used a a green gel filter.

Night Waterfall-Star Trails-Light Painting

Nikon D800 and Nikon 14-24mm lens. For the star trails, I shot 337 frames at ISO 1600, f/3.5, and a shutter speed of 30 seconds. For the waterfall, I shot separate frames and light painted the water with an LED flashlight and a blue gel filter. For the trees, I used a a green gel filter.

Look at the two examples in this article. I shot the individual frames for the first one at ISO 200 and a shutter speed of 4 minutes. The second one was ISO 1600 and a shutter speed of 30 seconds. The aperture was f/3.5 for both, so the total accumulative exposure was the same for both. (ISO 1600/30 seconds = ISO 800/60 seconds = ISO 400/120 seconds = ISO 200/ 4 minutes) But look at the difference in the star trails. The high ISO shot recorded tons of star trails filling up the sky.

At ISO 1600, the stars still show some color, so it’s really just a matter of personal preference as to which way you want to go. Oh, there is one practical consideration, and for me it’s a biggie. In order to get the same length of trails using the high ISO shot, I had to shoot a lot more frames. The first image is a stack of 52 4-minute exposures. The second one is a stack of 337 30-second exposures! And if you do the math, you’ll see that the 337 frames aren’t even enough to match the trail length in the first shot. I don’t know about you, but I have better things to do with my time than devote hours and hours to post-processing a 337-frame star trail. And besides, I like the look of the ISO 200 shot better, anyway.

I’m guessing you’d like some sort of formula or chart to help you determine which settings give you the best-looking stars. Sorry, no can do. I’m afraid there are just too many variables, among them the biggie of subjectivity. You’re going to have to do some testing with your own gear and use your own mind to figure out what the best settings are. But I can give you a general synopsis.

Low ISO/long shutter speed. With a low ISO (100 to 400), you get the more color in the stars and fewer stars show as trails. You also end up with fewer frames to work with in post processing.

High ISO/short shutter speed. With a high ISO (800 to 1600), you get less color in the stars (but you don’t lose all color) and more stars show as trails. You also end up a lot more frames to work with in post processing.

Really high ISO/really short shutter speed. If you go much above ISO 1600, you’ll lose a lot (or all) of the color in the stars and you’ll have a sky sardine-packed with white star trails. You’ll also have to deal with a huge number of frames in post processing.

Regardless of how you make the trails look, you have to choose an exposure that doesn’t blow out the sky. Unless you shoot in a very remote region, there is likely to be some amount of light pollution in the sky that will affect the exposure. The point at which this causes over exposure is called “sky-fog limit.” I can tell you that as a rule, in a relatively dark site, you can shoot an exposure of 8 minutes at ISO 200 and f/4, or any reciprocal of that. For example, 1 minute at ISO 1600. In a heavily light-polluted region, you might be lucky to get a minute at ISO 100.

At very dark sites, your shutter speed will be limited by noise, rather than the sky exposure. For pro digital cameras, you might get by with 30 minutes or more at a low ISO of 100 or 200, which would allow you to shoot a reasonable star-trail scene in one exposure. But, of course, if you want those long trails, you’ll have to shoot multiple exposures and stack them.

You should always make a few test exposures before you start the star-trail sequence to make sure you aren’t hitting the sky-fog limit. If you haven’t already tested your camera’s noise characteristics, you’ll want to test that as well. Even if the sky is dark enough for an eight-minute exposure, your camera might not give you good results at an exposure that long. As with any foreground light painting, I always make my tests using a different battery from the one used for the actual star trails. I want that one to be fresh out of the charger.

Speaking of exposure reciprocity, you can use that to your great advantage when making test exposures. Suppose you want to use a low ISO, say 100, so you get nice colorful star trails that don’t overwhelm the sky and you don’t want to fool with stacking tons of layers. You could spend a lot of time making test exposures of several minutes in length, or you could use reciprocity to shorten the time considerably. Crank the ISO to 6400 to make your tests. Suppose the test showed that an exposure of 8 seconds at ISO 6400 and f/4 is good. Do the math of reciprocity and you’ll see that that equates to an exposure of 8 minutes at ISO 100. You can’t test the noise this way, though.

One more thing about the sky exposure. A really cool technique is to begin or end the star trail series during twilight, so you get that nice blue-hour look in the sky. You don’t want to include too much of the twilight sky or else it will wash out the other exposures. And if you start exposing too soon, the twilight shot will be overexposed to begin with. Fortunately, this is easy to control. Simply start the star trails about midway through twilight, or let them continue through twilight in a morning session. Chances are good that you’ll capture one good twilight frame before it fades and you can stack this one with the regular star trails frames. Any twilight frames that come before this one (or after, in a morning shoot) you can trash.

How Long Should the Trails Be?

This is purely subjective. Personally, I like to go with a minimum of 30 minutes for the shutter speed and preferably an hour. Two or three hours is better. That’s at least 30 minutes of accumulative time. I probably wouldn’t shoot a 30-minute exposure for star trails, but would shoot six five-minute exposures instead. When I can, I load a fresh battery and shoot as many exposures as it will take, which is nearly four hours’ worth in my D800.

Using the Intervalometer

Few manuals ever written are as difficult to decipher as those provided with intervalometers. You’d think they were purposely trying to confuse us. I’ve been promising to write an easy-to-understand article about them for, oh, some five years now. I can tell you that it at present it is very high on my to-do list, so maybe you won’t have to wait too much longer.

In the meantime, I’m going to give you only the very basics and ask that you figure the rest out for yourself. Or feel free to shoot me an email and I’ll try to help you.

Most of the programmable intervalometers operate pretty much the same. The Nikon MC-36A and the Canon TC-80N3, as well as all of their aftermarket knockoffs, all use the same basic format. The first setting controls the delay, or how long the timer waits before starting the exposures. It works just like the self-timer in your camera. The next setting controls how long the exposure lasts. Next is the delay between exposures. (Canon has the previous two settings reversed.) Next is the total number of exposures desired. Finally, on the Nikon, there is a stupid control for whether or not you want to hear an annoying beep every time you make a setting on the timer. Trust me, you do not want to enable the beep!

Let’s say you want to shoot as many star trails as the camera battery allows with a shutter speed of four minutes, and you want to wait an hour before starting so most of the evening airplanes are gone. First, you need to set the camera shutter to bulb and single or continuous frame advance. Then you will set the intervalometer for 60 minutes for the delay, four minutes for the exposure length, one second for the interval, and either 399 or – – for the total number of exposures. The maximum number of exposures you can program in a Nikon timer is 399. With the Canon, it’s 99. For unlimited exposures, choose – – on the Nikon or 00 on the Canon. I rarely shoot more than 399 exposures, so I choose this instead of – -. Doing so lets me see the exposures count down on the timer. Update: On the Nikon MC-36A, you have to add the exposure length to the interval time. So in the above example, the interval setting would be four minutes and one second. 

With star trails, you obviously want the shortest interval between exposures, but the shortest you can program in the timer is one second. You can put 0 in there, but when you press the set button, it automatically changes to one second. That’s okay; with a wide-angle lens, one second is not going to cause a noticeable gap between the trails.

It’s not a good idea to let the intervalometer dangle in the wind during the star-trail capture. I glued a little loop on the back of mine so I can hang it from the hook on the bottom of the tripod center post. Another good idea is sticking it to a tripod leg with Velcro.

I like hanging it from the center post so that I can point it the direction I want, which is usually away from the direction I’m shooting. The intervalometer flashes a little red light when it is operating and I don’t want that light interfering with the exposures. Admittedly, that’s not likely to happen, but there is another reason to have the light aimed behind the camera. After you start the star-trail sequence, you’ll undoubtedly walk away from the camera to the car or a resting spot and return after the sequence is finished. Very often, I’ll return before the sequence is completely finished, so I can’t shine a flashing to light my way. That red flashing light works beautifully to keep me from stumbling into the tripod.

Dealing With Unwanted Lights in the Sky

You can pretty much count on having an airplane fly across the sky when shooting star trails. Chances are good there will be more than one, and other things like satellites or even fireflies that will interfere. It’s impossible to eliminate all of these elements during capture, but you can lessen their potential.

The best approach is to wait until late at night before you begin shooting. You’ll see a lot fewer planes after midnight than in the evening hours. The same is true for satellites and, for that matter, fireflies, although I don’t mind having a few firefly flashes in the scene. Of course, this also shortens the time you could be shooting, so depending on the location and whether you want to try for some twilight color in the sky, you might want to shoot right through the planes.

Sometimes you can shift the composition slightly and eliminate a lot of the planes. Pay attention as you get everything set up and you’ll likely see that most of the planes follow the same flight path. See if it’s possible to eliminate this path from the composition without ruining it.

Fireflies and star trails in the Smokies

Fireflies and star trails light up the sky at a historical house in the Smokies. I light painted the house in separate exposures from the star-trail captures.

Another issue is having other people or automobiles interfere with the image. If I’m shooting in a location where I think someone could come by and cause problems, I try to wait as late as possible before starting the star trail sequence. It’s not a problem if a car light interferes with a 30-second pinpoint star exposure, but you sure don’t want that happening in the middle of three-hour star trail!

You have to make a choice about any airplanes or other unwanted lights that show up in the finished image. You can leave them there, as some do, or you can spend a lot of tedious time removing them in post processing. Personally, I think airplanes ruin most star trail images, so I do whatever is necessary to remove them.

I’ve heard other photographers recommend removing airplane lights before stacking. The idea being that you can brush out the lights much easier when the star trails from only one exposure are present. You can simply paint a black streak over the airplane lights, since you’ll be stacking using the Lighten Blend Mode and the black streak won’t show up. This sounds good, but my experience shows that it doesn’t work very well. If you brush the streak out with black, it very likely will cause a residual effect in the final image. Even if you brush with the same color and lightness as the sky, I find it hard to prevent some residual effects from showing. So that leaves the only option of using regular image cleanup tools such as the Healing Brush or Clone Stamp. (Content Aware Fill doesn’t work well to remove airplane trails in this context. It just can’t seem to play nicely with the star trails.)

Since the only good option for removing airplane trails (in my opinion and based on my admitted limited knowledge of Photoshop) is the Spot Healing Brush and/or Clone Stamp tools, I find it much better to wait until all the layers are stacked and then just do all the airplane trails in one go. With these tools, it really doesn’t seem to matter how many star trails are around the airplane lights. But there is an even bigger advantage to waiting. With many star-trail photos, the sky in the finished stack is brighter than some of the airplane lights. The stacking process actually causes some of the plane lights to disappear. Less cleanup!

Miscellaneous Camera Settings for Star Trails

White Balance. I bought my first digital camera around 2005 and immediately set the white balance to Auto. I’m on my 5th camera model now, but the white balance is still on Auto. I shoot mostly in RAW, which means I can adjust the white balance to my heart’s content when I process the image. If you shoot JPEG, you’ll need to learn how to set the white balance. I’m not a good teacher for that.

Image Review. No need to waste battery power by having the image pop up on the LCD after every exposure. It’s not like you’re going to stand behind the camera and look at every one.

Mirror Lock. This one can bite you if you haven’t done some testing before you start the star trail sequence and discovered you have it enabled. With mirror lockup enabled, you can start the exposures and everything appears to work properly, but it’s not. I can’t tell you for sure about other cameras, but with most Nikons when you have mirror lockup enabled and press the shutter (or press the intervalometer when you’re shooting star trails), the mirror goes up but the camera doesn’t take the picture until you press the shutter again, which, of course, you won’t be doing when you shoot star trails. With Nikons, after 30 seconds the camera does take the picture, but you end up with 30-second gaps between the trails. This is not good, so make sure mirror lockup is turned off.

RAW Versus JPEG. If you aren’t shooting multiple shots for the foreground and you don’t plan ever to do any serious post processing, you can shoot JPEG and all will be just fine. But if you want the most image data available for making the finished photo look the best it can be, you should shoot RAW. The only time I shoot JPEG is for family events or in situations where I need to show or deliver photos immediately after the shoot. Sometimes I shoot RAW + JPEG. I shoot RAW with all night photography.

The comment I sometimes hear about having to process “all those RAW files” is a non-issue with star trails. I batch process the RAWs to change the white balance and convert to TIFF for stacking. That’s usually the only processing that’s done before stacking and flattened the file (except for dark-frame subtraction, discussed later), and since I do it in a batch process, it takes very little time.

There is another reason why I wouldn’t shoot JPEG for star trails, although I can’t say for sure if it is a valid one. I would be afraid that the processing performed by the camera software might cause problems with the star trails aligning perfectly. Again, I have no idea if this could happen, but I am suspicious.

Shutter. Set the shutter to bulb and the frame advance to single or continuous. The external timer will control the shutter speed and frame advance. Update: Both the Nikon and Canon manuals state to set the frame advance on the camera to Single. I haven’t had any issues with Continuous, but just in case you should set it to Single.

Long Exposure Noise Reduction (LENR). Read this article about LENR if you want the full scoop. All you really need to know is that LENR doubles the exposure time, so a four-minute star-trail exposure becomes an eight-minute one. So you end up with half of the exposures you wanted and a gap between them that equals your exposure time. With star trails, you should make sure LENR is turned off. Some cameras have this enabled by default, so be careful.

High ISO Noise Reduction is different. I can’t say for certain about other cameras, but I know that it doesn’t affect RAW files in the Nikon D700 and D800, and I assume other Nikons as well. It writes a tag to the file. Nikon’s Capture NX reads this tag and applies the noise reduction algorithm to the RAW file when it is converted. Adobe Camera RAW cannot read the tag, and I assume no other software besides Nikon’s can either. So, if you shoot RAW, HIGH ISO NR will have no effect on the photo. It only affects JPEGs and the LCD preview image on the camera.

Dealing With Noise

Since you can’t use LENR for star trails, you might think that noise is going to be a big problem. In some cases, it is. I can promise you that if you shoot long trails on a hot summer night, especially at high ISOs, you’re going to have noise issues.

The best way to minimize noise in capture is by shooting at low ISOs and keeping the shutter speeds to around five minutes or less. Shooting in cold temperatures makes a huge difference, but you don’t want to limit your star trails to winter.

If the noise is enough to cause image degradation, you can deal with it to some extent during post processing. Random noise can be removed very well using Lightroom or Photoshop, although with an unavoidable loss of sharpness. I use a Photoshop plugin called Nik Dfine for noise, which works very well.

However, there is another kind of noise that can’t be removed well with noise-removal software and that’s what is sometimes called “hot-pixel noise.” It’s those little colored pixel dots that show up all over the image during long exposures. LENR does remove this kind of noise, but as discussed above, you can’t use LENR with star trails.

You have two options, neither of them anywhere close to being as pleasant as laying on a hot beach while drinking a cold beer. One option is to capture your own “dark frames” and manually perform the same LENR that the camera does, but in Photoshop. This works very well, but it adds another level to the complexity of creating a star-trail image, along with a considerable amount of time. If you want to try it, I’ll give you instructions in a few minutes.

The other option is using the image cleanup tools in Lightroom or Photoshop to remove the light specs. How long and how difficult this task is will depend on how much noise was present to begin with, how much sky is in the image (it’s much easier to clean up noise in the foreground), how bright the sky is (some of the noise will be hidden if the sky is bright enough), and where exactly the noise is located in the image (if it’s under a bright star trail, it might not show up). I spend anywhere from a few minutes to several hours cleaning my images.

The tools I use for cleaning up hot-pixel noise are the Spot Healing Brush and the Clone Stamp tools. Typically, I use the Spot Healing Brush for noise that’s in the foreground and the Clone Stamp for any noise in the sky. I find the Clone Stamp much easier when dealing with the star trails. I should make it clear that I’m not even close to being an expert on Photoshop and you may find other approaches that work better.

By the way, all noise reduction processing, except for dark-frame subtraction, should be done after you stack the individual frames. In fact, nearly all processing needs to come afterward. The only things that you can safely do before stacking are linear adjustments such as white balance and you should you make the same adjustments to all of the photos. Otherwise, you risk the chance of the star trails, or even the foreground elements, not stacking precisely.

Using Dark Frames to Reduce Noise

We can’t use Long Exposure Noise Reduction (LENR) when shooting star trails because it doubles the exposure time, taking away the goal of having the shortest amount of time possible between exposures so gaps won’t show. However, we can perform the same function manually. It’s actually pretty simple once you get the hang of it, but it does take some time.

First, a little background on how LENR works. LENR is based on the fact that two identical exposures that are shot successively will display the same noise characteristics. As long as the shutter speed, ISO, and temperature are the same, and as long as there has not been a long interval between the shots (noise increases as the camera gets older), each photo will have almost precisely the same noise. And here’s the important part: The noise records regardless of whether there is any light coming through the lens. In other words, you could put the lens cap on for one of the exposures and both photos will still display the same noise.

This is important because it gives the camera a way not only to measure the noise, but also to remove it. With LENR enabled, you shoot the photo just as you normally would, but after the exposure is finished, the camera takes a second exposure, using the same settings, but without allowing any light to reach the sensor. This second exposure records only the noise, the same noise that recorded on the first shot. So now the camera has two photos to work with, one with the picture you shot, which we call the “light frame” and one that shows only the noise. The second frame is referred to as a “dark frame” because it did not record any light.

The camera software looks at the dark frame, measures all the noise, and determines precisely where it is located on the frame. Then it goes back to the light frame and plucks away all the noise that it measured. The process is called “dark frame subtraction.” There are different kinds of noise and the camera can’t get rid of all them. It does a good job of removing “hot” or “stuck” pixels—those tiny blue, red, or green squares or rectangles—and it will remove “amp glow”—the purple or pinkish color that shows on the corners of the frame when the sensor heats up. But it won’t remove “random noise,” which makes up the bulk of what we perceive as noise in an image. As stated above, random noise can be reduced using post-processing software.

Long Exposure Noise Reduction example photo

60 seconds, ISO 800, Nikon D800. Long Exposure Noise Reduction disabled. 200% crop. Curves adjustment layer applied to illustrate the effect better.

Long Exposure Noise Reduction example photo

60 seconds, ISO 800, Nikon D800. Long Exposure Noise Reduction enabled. 200% crop. Curves adjustment layer applied to illustrate the effect better.

The example photos above illustrate the effectiveness of using LENR in the camera, but the result is the same as if I had done so manually. I just don’t have any examples handy for the manual process.

To perform dark frame subtraction manually, you first have to create one or more dark frames. One works fine—that’s all the camera uses—but you can get slightly better results by shooting three or four frames and averaging them together.

Here’s how to shoot them. First, make sure the exposure settings are the same as what you’re shooting for the star trails. Aperture doesn’t matter, but ISO and shutter speed must be identical. Next, make sure no light can enter the lens or the back of the camera. I put the lens cap on and cover the camera with an opaque black cloth. Now, simply shoot an exposure just as you would for the star trails.

Since temperature affects noise, you need to shoot the dark frame either right before or right after you capture the star trails and before you pack the camera in a warm car. I usually shoot at least two dark frames, one before and one after. Sometimes, if there’s time, I’ll shoot several frames afterward. I carry my camera in the back of my truck in an unheated space and very often I’ll shoot a series of dark frames as I’m driving down the highway. The only problem with shooting the dark frames after you remove the camera from the tripod is that the camera gets confused about the proper orientation of the frames and will make a vertical a horizontal or the opposite. So you have to be careful to rotate the frames correctly. They must be oriented the same as the light frames or the noise removal won’t work.

If you capture two or more dark frames, you have to average them together before you can use them. Load them as layers in Photoshop and keep the Blend Mode set to Normal. Now you need to change the Opacity of each layer so the software can see through them to the layer beneath. If you have two layers, change the opacity of the top layer to 50%. For three layers, change the second layer to 50% and the top layer to 33%. For four layers, change the second layer to 50%, the third layer to 33%, and the top layer to 25%. And so on.

Once you set the opacities for each layer, flatten the file into what we call the “master dark frame.” I don’t know why averaging multiple dark frames results in a better noise removal, but it does help. I know some photographers who shoot 15 or 20 dark frames, but the testing I’ve done shows that there is no appreciable advantage beyond four or five, and as I said, one will do the job nicely.

Once you get the master or single dark frame, stack it as a layer on top of the star-trail light frame. Make sure the opacity for both layers is set to 100%. Now change the Blend Mode to Difference, and the noise magically disappears. That’s all there is to it!

Except that isn’t exactly all there is to it. As best as I can tell, you have to perform the dark frame subtraction on every star-trail exposure before you stack them. I’m sure there must be a way to set up a Photoshop action to do this, but I can’t figure it out. So I have to do it manually for every shot. Fortunately, I do use an action for setting the White Balance and converting to TIFF (which is necessary in order to work in StarStaX), but the dark-frame subtraction does take time. Is it worth it? Yes, I think so. I’d spend as much or more time cleaning up those dang specs with the Clone Stamp tool.

Remember, we have to go through all this because we are shooting star trails, where we want the shortest interval possible between exposures. You’d also want to do it for a few other types of night photography, such as shooting meteors and some types of time lapses. But for other scenarios, it’s far easier to enable LENR and let the camera do all the work.

Stacking The Layers And Post Processing

Stacking all the exposures can be as simple as you want it to be. For the simplest method, download the free StarStaX software and point it at the folder of exposures. It will do all the work for you. You can get a little more involved with it by setting up the preferences to your liking or just leave everything on default as many people do. Done!

So if that’s all there is to it, why the fuss, and what’s all this about Photoshop and other stuff? Because that’s not really all there is to it. (You were afraid I was going to say that, weren’t you?) Yes, StarStaX will assemble your star trail image for you, but it only works with the star-trail exposures. It won’t stack the foreground exposure as well. Well, it will stack them, but it won’t allow you to do any individual adjustments to them before or after they are stacked, which is the beauty of working with layers in Photoshop.

For the foreground images, you need to stack them first and do any desired adjustments before stacking them with the star trails. The adjustments you make are up to you—contrast, saturation, exposure, color balance, or whatever else you want to do. However, in nearly every case, one of those adjustments is going to have to be brushing out the sky from the foreground image. Otherwise, the stars in the sky of the foreground image will show up in the star-trail layer.

So you’re looking at getting into Photoshop anyway for all but the most basic star-trail image. Yes, I did mention the option of doing the light painting in the same exposures as the star trails and then simply letting StarStaX do everything. This is certainly a viable option for those who don’t have Photoshop and don’t want to get it. You just need to understand that it will be just as difficult to get your light painting perfect during your star-trail exposures as it will be to figure out how to work with layers in Photoshop. Don’t have PS and don’t want to get it? I understand. But if you do have it, do yourself a favor and learn the basics of layers and layer masks. And, by the way, Lightroom does not have layering capability.

More About the Choice of Light Painting and Using Photoshop

I know some photographers who simply will not consider using Photoshop and I know some who do not care to do any type of light painting. But they do like star trails. If you’re one of them, guess what? That’s okay! They’re your photos; you can shoot and process them however you like.

If you don’t light paint the foreground, or, more specifically, you don’t paint it in multiple exposures that need to be blended and processed before stacking with the star-trail layers, and you don’t want to use Photoshop, you can simply take all of your exposures and let StarStaX do everything for you. And if you plan your shots carefully, it is definitely possible to create some great star-trail images this way.

Stacking In Photoshop

Stacking the images is crazy easy. From Bridge, simply select them, then go to Tools>Photoshop>Load Files into Photoshop Layers. Then, depending on how many images you have and how fast your computer is, you will have enough time for only a sip of wine or you’ll have time to go out and grow the grapes, crush them, and let the juice ferment before the layer stack magically appears. You don’t even have to have Photoshop open, as Bridge will open it for you. That was easy!

So is this. Once all the layers are piled up in the Layers Palate, you need to change the Blend Mode to Lighten in order for all the star trails to show up. In CS6 and newer, you can select all of the layers at once (just as you would select multiple photos in a folder) and change the Blend Mode for all. In earlier versions, you have to select each layer separately. Once the Blend Mode is set to Lighten for all layers, you Flatten the file (Layer>Flatten Image) to create a single image file.

The result you see on the screen will be pretty much the same as what you’d see if you let StarStaX do the work for you. Then what’s the advantage of using Photoshop? Hey, we’re just getting started here. Patience!

For the star trails, there is really only one advantage of using Photoshop for the stacking and that is to eliminate the gaps that appear between each trail. More on that later. But for the foreground, there is the huge advantage of being able to work on each layer individually. By using masks, you can erase parts from each layer and make selective adjustments on them. You can even change the opacities of the layers individually. Got a little hot with the light painting on the trunk of that tree? No problem. Just brush out that part of the light painting from that layer.

I’m not going to go into all the details of layers and masks in Photoshop for two reasons. One is because my two typing fingers are tired. But the biggest reason is that I’m not qualified. I hunt and peck and get by the best I can in Photoshop, but I’m not qualified to teach it. The upshot of that is if I can do it, you can too! A few hours spent with Google should have you moving along nicely.

My Star Trails Need Braces!

The problem with using StarStaX or Photoshop (or any other software) to stack your star trails is that it leaves tiny little gaps between the trails. This is not caused by the one-second interval between exposures that the timer requires. One second is not enough to be noticeable in a wide-angle view. It’s caused by the way the software stacks the layers, but that’s the extent of my knowledge on the subject. All I know is that they are there and I don’t like them.

Star trails

This is what star trails look like if you don't fill the gaps between the trails. It is much more obvious at higher magnifications.

If all you ever do is post your photos on Facebook or a blog, you can get by with leaving the gaps there. But if you want to make a decent-sized print, or if you’re like me and just can’t stand the thought of your star trails needing braces, you gotta get rid of those gaps. I’ve read of several methods for removing them, such as using the Clone Stamp tool or making a duplicate layer and slightly shifting one layer onto the other. Trying to clone in the gaps on a star trail image could literally take days (weeks for high-ISO shots) and would be extremely difficult to make them look just right. Making a duplicate layer and shifting it simply won’t work, at least not for any star trail I shoot. The only way I can see it working is if you use a telephoto lens for the shot. With a wide angle, there is going to be too much distortion in the lines and too much variation in their curvatures.

StarStaX features a gap-filling option, but I haven’t used it. I did read the instructions and once I learned the process it uses to fill the gaps, I realized that it doesn’t provide a good, fill-all-the-gaps-all-the-time solution. Even the example photo shown in the tutorial still has gaps in some of the trails after going through the process.

So what does that leave? Thank goodness for smart people! One of them is an exceptionally talented photographer named Floris van Breugal. Floris figured out how to remove the gaps using a special blending mode technique in Photoshop. I started using the technique immediately after reading about it and I can report that it works beautifully. The only problem is that it is very time consuming and consumes a lot of processing power. When I have a large batch of star trails to assemble, I have to break them down into batches of around 30 or else it crashes my computer.

Actually, I don’t have that problem any longer because Floris created a script that will do the stacking and gap filling automatically. And if that’s not enough, he offers the script free! Floris, you are my hero!

You can read his tutorial on filling the gaps manually and download his free script here. While you’re on his site, spend some time browsing his images and reading his articles. This is one talented individual!

You’re Not Done Yet

After you get the star trails stacked, you still have some work to do if you want the image to look its best. As discussed above, you may need to do some noise reduction and you certainly will need to do at least a little image cleanup to get rid of dust specs, hot pixels, airplane trails, and the like.

Most wide-angle lenses suffer from chromatic aberration, which means that red, green, and blue light is not focused at precisely the same point. Magnify the image to 100, or better yet 200 percent, and examine the image. If chromatic aberration is present, it will show as a colored fringe along the edges of the star trails. There is no way I know of to prevent it from happening while shooting, but it is very easy to correct in post processing. In Photoshop, go to Filter and then Lens Correction. The automatic setting works very well most of the time, but you can adjust it manually if needed.

Of course, there are lots of other adjustments you can and may wish to do with the image. Contrast, color balance, saturation, and sharpening are a few of the ones I consider. For nearly every image, I perform at least a slight Curves adjustment to boost contrast and apply an Unsharp Mask to sharpen the image. You should do whatever you like with your own images.

Checklist for Capturing And Processing Star Trail Images

I realize I’ve taken you on quite a ride and it may be a little hard to figure out how to proceed. Hopefully, these checklists will help organize your thoughts.

Capturing Star Trails

  1. Plan the shot ahead as much as you can.
  2. Arrive before it gets dark if possible.
  3. Choose the general composition, taking into consideration how much of the scene will appear black if you set up before it gets dark.
  4. Set up tripod as sturdy as you can. Makes sure the feet are firmly seated in the ground. Do not extend the legs any farther than absolutely necessary. DO NOT extend the center post.
  5. Make sure front element of lens is clean.
  6. Turn off image stabilization.
  7. Mount camera on tripod and lock in the composition. (Assuming your tripod head has a quick-release clamp so that you can remove and remount the camera without affecting the composition.)
  8. If setting up after dark, make a test photo at very high ISO and perhaps throwing in some light with a flashlight. This test is to make sure the composition is right. The exposure test comes later.
  9. Tape the lens focus barrel unless you are focusing manually, in which case you will tape it after acquiring focus.
  10. Focus the camera. It is perfectly acceptable (even desirable in most cases) to remove the camera from the tripod and point it where you need it to get the focus set. Remount camera on tripod after focus is set.
  11. Turn autofocus off.
  12. If there is a possibly for dew to form, attach dew heater strips or LensMuff™ to the lens.
  13. Secure camera strap so it doesn’t blow in the wind.
  14. Acquire foreground shots if you are shooting them separately. Choose camera settings that work best for foreground, not sky.
  15. Make test exposures to determine proper exposure settings for the star trails.
  16. Attach intervalometer to the camera and program it as desired.
  17. Check all settings on camera. Long Exposure Noise Reduction off, Auto Bracketing off, Mirror Lockup off, frame advance to Single, shutter on Bulb, Aperture and ISO as desired, Image Review off, image quality RAW, White Balance Auto (unless capturing in JPEG).
  18. Make sure memory card has enough capacity for all the exposures.
  19. Acquire one dark frame if desired.
  20. Install fresh battery.
  21. Start intervalometer. For extra assurance, I always wait for one exposure to complete to make sure the timer is working properly. I hold my ear close to the camera so I can hear it advance to the next frame.
  22. After you finish capturing star trails, acquire more dark frames if desired.

Processing Star Trails

Really Simple Method

  1. Point StarStaX at a folder of captures and let it do all the work. Will not work if you captured foreground images separately from the star-trail captures.

Simple Method

  1. Point StarStaX at a folder of captures and let it do all the work. Take finished image from StarStaX and open it software of choice for image cleanup and tweaking. Will not work if you captured foreground images separately from the star-trail captures.

Somewhat Simple Method

  1. Open foreground capture (s) in Photoshop or software of choice and process them as desired. Brush out the sky so the stars or any airplane trails don’t interfere with the star trails. If you have multiple foreground shots, flattened the file before brushing sky.
  2. Load processed foreground image in folder with star trails.
  3. Point StarStaX at folder and let it stack everything.
  4. Take finished image from StarStaX and open it in software of choice for further image cleanup and tweaking.

Time Consuming and Tedious Gap Filling Method

  1. Open foreground capture (s) in Photoshop or software of choice and process them as desired. Brush out the sky so the stars or any airplane trails don’t interfere with the star trails. If you have multiple foreground shots, flattened the file before brushing sky.
  2. Load star-trail captures as layers in Photoshop.
  3. Follow instructions in Floris van Breugal tutorial for filling gaps.
  4. Flatten file and make any adjustments and image cleanup desired.
  5. Stack foreground image with star trail layer in Photoshop.

Kevin Adams Method

  1. Open foreground capture (s) in Photoshop and process as desired. Brush out the sky so the stars or any airplane trails don’t interfere with the star trails. If you have multiple foreground shots, flattened the file before brushing sky.
  2. Use script from Floris van Breugal to stack star-trail captures and fill gaps. Allow script to flatten file automatically when finished.
  3. Using Photoshop, make any adjustments and image cleanup desired to the star-trail image.
  4. Stack foreground image with star-trail layer in Photoshop.
  5. Perform any tweaking as desired in Photoshop.

Okay, I’ll shut up now.

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