How to shoot and process star trail photographs | Complete Guide
Nighttime and start trail photography can be a rewarding endeavor but it can also be challenging due to the lack of a light. In this article I will explain how to shoot and process star-trail photographs from start to finish. First, I’ll cover the required gear, then I discuss proper focusing and shooting techniques. Lastly, I'll demonstrate how to edit and combine multiple shots into a single image with long star streaks in the sky.
Full disclosure: Some of the links in this article are affiliate links which may give me a small kick back. I never recommend products or services that I would not use myself. If you enjoy this article and plan on making a purchase, please do so by clicking one of the links.
If you prefer a video over this article, watch my "How To Shoot and Process Star Trail Photos" video below.
How do star Trails Happen in Photography?
The Earth is constantly spinning. That's why we have day and night. Since the earth is rotating, stars appear to slowly move across the night sky. This movement is what allows us to photograph star trails with long exposures. (More on that in a minute)
Required Gear For Photographing Star Trails
Start trail photography requires only a small amount of gear to get started. While high end gear can help produce better results, even an entry level setup will be enough to get you started.
The camera is obviously an important part of the night time photography process so we’ll start there. You can shoot star-trails with just about any camera that can shoot for longer than 30 seconds but not all cameras are created equal. A full frame sensor will handle long exposures and low light much better than a crop sensor camera such as APS-C or Micro four thirds. Larger sensors have larger pixels which means they can collect more light and produce less noise with one caveat. High megapixel cameras have more pixels crammed onto the sensor which equates to smaller pixel size. Lower megapixel cameras have larger pixels which results in better light collecting capabilities in most cases. With that being said, the best camera is the one that you own. Don’t get the impression that you need to upgrade your camera to learn astrophotography. Go out and experiment and have fun. If you find yourself doing a lot of night photography, then you might consider upgrading to a full frame if you do not already own one.
Lenses For Star-trails
Photographing the Milky Way requires a fast ultra-wide lens to freeze the stars in place, but just about any wide or mid-range lens can be used for star-trails. The subject that you are photographing in the foreground will determine the appropriate focal length to use. While a wide-angle lens will allow you to include more sky and get closer to smaller subjects, large subjects that are farther away can be shot with a mid-range or even telephoto lens. Keep in mind that you will not be able to include much of the sky with longer lenses though.
NOTE: Wide angle lenses take longer to produce star-trails than mid-range or telephotos lenses due to the wider angle of view.
Tripods come in many different sizes. Some are just about useless while others will cost an arm and a leg. The good news is that you do not need an expensive tripod, you simply need a sturdy tripod. Read my “Game Changing Camera Gear” article for tripod recommendations.
Intervalometers & Star-trails
In the days of film, photographers would simply lock open the shutter with a cable release and close it again when a specified amount of time had passed. In the digital age, camera sensors get hot when they shoot for long periods of time and hot sensors create noise. As a general rule of thumb, it is best to keep exposure times down to five minutes and shorter whenever possible. Five minutes is not long enough to get meaningful star-trails with a wide or mid-range lens though. This is where the intervalometer comes in.
An intervalometer is an essential piece of gear for star-trail photography. These devices allow the photographer to program in a specified number of shots, exposure time and interval. Due to Murphy’s law, (What can go wrong, will go wrong) I only recommend using a wired intervalometer so you do not have to worry about connectivity issues when you’re out in the field shooting. Another thing to note is that name brand intervalometers can be quite costly. Third party intervalometers can be picked up for a fraction of the price.
Intervalometer Settings For Star Trails
If you are new to using an intervalometer, I highly recommend watching my “How to Shoot and Process Star Trail Photos” video where I walk through the intervalometer programming process.
Below you’ll find the proper intervalometer settings to shoot star trails.
• Delay: 0
• Length: 4-5 Min
• Interval: 1 second (less time if your interval has that option)
• Number of Shots: Set to (--) if you want to shoot indefinitely, otherwise 15 shots will give you one hour shooting at 4 minutes. 45 - 75 minutes is generally a good shooting time when using ultra-wide lenses.
• Turn sound off: (Trust me)
Camera Settings for Star Trails
The amount of moonlight on a given night will determine the settings that you use. Nights with a lot of moonlight are much brighter than nights with no moon light at all. While it is impossible to give the exact camera settings needed to obtain a perfect exposure at night, it is possible to get close. I have listed some starting point star trail camera settings for full moon and no moon nights below. If you have a partial moon, you’ll simply have to split the difference.
IMPORTANT: Make sure you turn off “long exposure noise reduction” before attempting to shoot star trails. If Long Expo NR is left on, the camera takes one dark frame after the initial exposure to conduct in camera noise reduction. This process takes just as long as the exposure time so you’ll end up with dotted star trails if you do not turn it off.
CAMERA SETTINGS FOR STAR TRAILS AND A FULL MOON
• Bulb Mode
• Shutter Speed: 4-5 minutes
• Aperture: f/8
• ISO: 640
• White Balance: 4,200 K
CAMERA SETTINGS FOR STAR TRAILS WITH WITH NO MOONLIGHT
• Bulb Mode
• Shutter Speed: 4-5 minutes
• Aperture: f/4
• ISO: 1250
• White Balance: 3,200 - 4,200 K
How to Find The North Stat (Northern Hemisphere Only)
If you want the stars to rotate around a single star, you’ll have to include the north star in your photograph. Finding the north star is relatively easy even without the use of a phone app and is a good skill to have if you plan on doing any amount of nighttime shooting.
To find the north star you'll first want to find the find the big dipper. The big dipper is one of the most prominent constellations in the night sky and is relatively easy to find. Once you find the big dipper, follow the last two stars that make up the cup portion in a straight line to the handle of the little dipper. The last star in the handle of the little dipper is the north star! It is a relatively dim star but easy to find when you use this technique.
Focusing your camera at Night
Now for the fun part! (Not really) Focusing at night or in low light can prove to be rather challenging. Autofocus will not work in lowlight so you’re going to have to switch your lens to manual focus and do the heavy lifting yourself.
Before I continue, it’s important to note that not all cameras see in the dark the same. If you’re a canon shooter, you’re in luck because Canon cameras tend to see in the dark better than the rest of the mainstream camera brands. Canon does a really good job of delivering a high gain / low noise image to the LCD screen and or electronic viewfinder to help with focusing. Sony does an ok job of seeing in low light and lastly Nikon… Well let’s just say that Nikon is getting better than they used to be about lowlight gain on the LCD screen. If you are shooting on an older Nikon (Anything older than a Nikon D850) you are going to have some serious troubles trying to focus at night due to all of the noise in the LCD screen.
HOW TO FOCUS ON A STAR
With any type of astrophotography, it is absolutely essential that the stars are sharp. In order to obtain sharp stars, we’ll need to focus on infinity. The infinity point is often not at the very end of focus though so you cannot just rotate the focus until it reaches the infinity marking on the lens and shoot. The infinity marking on the lens is a good starting position to focus on the stars though because the infinity point will be somewhere near it. If the focus is too far off from infinity, the stars will be so blurry that they will not even show up on the LCD screen or EVF.
NOTE: Many mirrorless lenses do not have focus marking on the lens like tradition SLR and DSLR lenses do. Because of this, you might have to do a little bit of experimenting to find out which direction infinity is.
The infinity point is always towards the back of the focus range. Rack your focus ring back and forth to see which direction the focus is moving. If the focus is coming closer to the camera you are going in the wrong direction. If the focus is moving away from the camera you're heading the right direction. Keep rotating the focus ring until you reach the end of the focus range. You're now near infinity and ready to focus on a star.
Now that we have our lens focused somewhere near infinity, we’ll need to change some cameras settings to help our camera see in the dark. First and foremost, I always set my camera to manual mode when focusing, even if I plan on shooting in Bulb mode later on. Manual Mode tends to give a little more gain than bulb mode does. Before you start changing other camera settings, it’s a good idea to make sure that your camera is set to “Exposure Preview”. This will provide the best results on most cameras.
Ok, let’s adjust our exposure settings now. Set the shutter speed to 30 seconds, open up the aperture to its widest setting. (f.2.8 or f/4 is ideal if your lens will open up that much. Finally, crank up the ISO to something around 6,400 or 8,000. These settings really increase the gain and the ability of the camera to see in the dark.
Once you have your gain cranked up, look at the night sky, search for a bright star and point your camera in its general direction. If you’re lucky, you’ll be able to see the star on the back of the LCD screen without even digitally zooming in. I would not plan on that scenario though. You will most likely have to hit the camera’s magnifying glass button to digitally zoom into the image. Once you are zoomed in, you can move around the image in search of a star. Keep in mind that your focus needs to be set near infinity. If you’re having trouble finding a star rack the focus ring back and forth slightly to see if any stars become visible. Once you find a star, go ahead and rack the focus ring back and forth until the star is as sharp as it can possibly be. Depending on your camera, available light and the quality of your vision, focusing on a star can sometime be frustrating. Don’t give up though. It may take a few attempts before you get the hang of it.
Once you obtain focus, be very careful not to bump the focus ring or change the zoom. If you change the zoom, you’ll have to focus all over again.
What To Do If You Can't Focus Your Camera At Night
As mentioned above, not all cameras see in the dark the same. If you are shooting on an older camera, it may be very difficult to focus on a star. If this is the case, try to focus on the moon if it is up on the night you’re shooting. Focusing on the moon is nearly the same as focusing on a star, except the moon is much brighter and bigger which makes it a little easier to focus on. Since the moon is much brighter than the stars, you will not need to crank the ISO as high and you might be able to get away with as short shutter speed as well. When you’re focusing on the moon you do not want to overexpose it. You want the exposure to be dark enough to see texture on the moon.
If you cannot focus at night and do not have a moon, the next best thing is to focus on the furthest thing away from the camera before it gets dark. If there’s a mountain off in the distance, focus on that. The mountain will be at infinity and you’ll be able to obtain sharp stars in your photograph. Remember not to bump the lens or change focus or zoom once you obtain focus on infinity.
Depth of Field in Astrophotography
Whenever you’re shooting at night, you’ll most likely be shooting with a fairly open aperture. This means that you’ll also have a fairly shallow depth of field. As mentioned above, it is essential that the stars are in focus. This means that the foreground will be soft if you’re too close to your subject. In order to avoid a soft foreground, consider shooting with a wide lens and give some space between the lens and subject. You could also shoot when there is more moonlight which will allow you to close down the aperture a little bit and get a little more depth of field.
Alternatively, you could try to focus stack the scene but focus stacking at night can be rather difficult and produce some post processing headaches. Due to the advanced nature of night focus stacking, I’ll save that subject for another article.
Histograms and Night Photography
If you’ve been on a photography workshop with me, you know that I’m constantly reminding people to check their histograms. Unfortunately, histograms do not function at night in the same way that they do in the daytime. They can still be a helpful tool though. When shooting at night You’ll want to make sure that you are pushing the histogram away from the left edge of the graph. It is very easy to under expose nighttime photographs because of the low ambient light and bright LCD screen. Making sure that you push the histogram away from the left edge will help ensure that you are not under exposing your photographs. It's important not to under expose your images because increasing the exposure of a dark-high-ISO-photograph will most certainly result in a lot of unwanted noise.
Night Photography Filters For Light Pollution
No filters are required to shoot at night. It is best practice to remove UV and PL filters for night shooting. PL filters darken the image so leaving one on at night is a very bad idea. UV filters are harmless in most cases but can create strange refractions at night, especially if you’re shooting a scene with electric lights in it. Night filters can be used to help reduce light pollution and give the sky more of a blue hue. These filters are helpful because it is very hard to remove light pollution in post processing. Hue adjustments done to high ISO images often result in blotching in the sky. Breakthrough makes a great night filter if you're interested in using one.
The amount of light cast onto a night scene will vary greatly depending on moonlight, light pollution, and cloud cover. If there is no moonlight, you can still shoot the night sky but your foreground will be a black silhouette. In order to shed some literal light on the situation, you can use a flashlight or headlamp to light up your foreground if it is relatively close. The amount of light that you need with vary greatly depending on the size of the scene.
LIGHT PAINTING TECHNIQUE
Light painting is the process of shining a light on a scene that would otherwise be dark. When using an artificial light to illuminate a scene it is important to consider the direction you are lighting from. It can be tempting to light the scene from the same spot that you’re shooting it from but this technique will result in flat light with no shadows.
A better technique is to light the scene at an angle from the lens. The exact angle will depend on the landscape that you’re shooting, but somewhere between 45 and 90 degrees from the camera will be a good starting point. The amount of time you need to light the scene will depend on the brightness of your light and the size of the scene. It will take a little bit of experimenting to get your light painting right so don’t get discouraged if it doesn’t go exactly as planed the first time you try it.
Multiple light painted shots can be blended together in photoshop if the scene is too big to light up within a single exposure. Watch the processing section of my “How to Shoot and Process Star Trail Photos” video to see how I blend multiple light painted images together in Photoshop.
NOTE: If you have a good grasp on layer masking in Photoshop, you can shoot the light painted shots at a lower ISO than the star shots. You'll simply have to mask out the sky of the light painted shots in post.
Light Painting Instruments
I always cary a powerful headlamp and spare batteries in my camera bag at all times, even if I do not plan on shooting at night. You can never be too prepared. My go-to headlamp is the Petzel Actik Core which operates on a rechargeable battery pack or 3 AAA batteries if you you’re in a pinch. The headlamp is 600 lumens and has three brightness settings. It also features a red light option to preserve your night vision. I have done a lot of light painting with this headlamp. It is plenty bright for close range subjects
HIGH POWER FLASHLIGHT
If you think you might be shooting large scenes that need a lot of illumination, you might want to consider purchasing a high power flashlight such as the NiteCore P20ix. This 4,000 lumen flashlight has seven brightness settings and will be more than enough to light paint almost any scene.
LED lights are naturally slightly blue in color. You can balance out the blue cast by placing an orange color correcting gel in front of your headlamp or flashlight.
Other Nighttime Shooting Considerations
Shooting at night requires a significant amount of time investment so it is best to be as prepared as possible when conducting a shoot. Below are few considerations to take into account before any nighttime photography shoot.
BATTERIES: Before heading out to shoot, make sure that all your batteries are completely charged. Shooting long exposures will drain your batteries quicker than normal. Cold weather will further exacerbate the situation.
DEW: Dew can be a problem in some climates. This is especially true if you’re going to leave your camera outside at night for a long period of time. If you plan to shoot in an area that might be prone to dew, its a good idea to purchase a lens warmer and powerful batter pack in order to keep your lens from collecting condensation.
Planning Apps and Websites
There are plenty of planning apps and websites to help you prepare for your nighttime photography session.
WEATHER AND CLEAR SKIES
Clouds are not friends to astro-photographers. Luckily, there are a few websites to help plan for clear skies.
• Clear Dark Sky is a great website to check for cloud conditions and light pollution in the US and Canada.
• Clear Outside is a good cloud condition website for Europe.
No mater where you’re located, it’s a good idea to check the local weather forecast in conjunction with these websites. No weather forecast is perfect, and you could still end up with cloudy skies even when the forecast predicts otherwise.
• Windy is a great phone-based app that allows users to compare five different weather forecast models with one another. The down side is that this app perfectly demonstrates how hard it is to predict the weather, as the forecasts often contradict one another. Windy also has a great website that is very similar to the app.
NIGHT PLANNING APPS
The Photographer Ephemeris and PhotoPills are great planning apps that every landscape photographer should consider owning. The two apps are quite similar when it comes to planning with a few distinct differences. Both apps do a great job of displaying sun, moon and Milky Way paths with map and augmented reality view modes. TPE features a light pollution overlay which can be very helpful when you’re planning a nighttime shoot and Photo Pills has an exposure calculator along with many other features that I do not have time to go into for this particular article.
Gear Checklist Before You head Out Into the Night
• Wide Lens
• Tripod & Ballhead
• Empty Memory Card
• Spare Camera Batteries
• Intervalometer & Spare Batteries
• Spare Headlamp Batteries
• USB Charging Bank
• Phone Charging Cord
Pre Shoot Checklist
● Plug in your intervalometer before mounting your camera on the tripod.
● Make sure that you’re shooting in RAW
● 100% Charged Battery
● Make sure you have enough room on your memory card for your shoot (Especially if
you are shooting star trails)
● No filters on the lens unless you are using a specific night filter.
● Make sure your lens is set to manual focus
● Turn image stabilization off if your lens or camera is equipped with it.
● Check long exposure noise reduction settings. (Must be off for star trails!)
● Check camera mode (Manual for pinpoint stars, Bulb for star trails)
● Set your White Balance to your preferences. (3,200 K - 4,000 K)
● Focus on a bright star
How To Process RAW Files for Star Trails
For best results, we must first process our RAW photos in Lightroom or a similar Raw editor before creating our star trail composite in Photoshop. Below are some basic adjustments that you should consider doing to your RAW files.
Consider Alternate Profiles: Lightroom’s default Color Profile is Adobe Color. If your images are dark to start off with, you may consider using Adobe Neutral. This profile will lighten the sky and then you can darken any areas that you need using exposure, dehaze or black local adjustments
White Balance / Tint: Adjust the white balance to the color that you prefer. I like my night images on the cooler side but some people prefer a more neutral look. If your sky has a bit of a green color cast you can move the tint slider toward magenta.
Tonal Adjustments: If you think your image is on the dark side, use the exposure slider to give it a boost. I typically avoid boosting the shadows and blacks too much because it can add quite a bit of noise. Boosting the “whites” sliders is a great way to make the stars pop.
Tone Curve: Boost the lights in order to give a pop to the stars. If you need to add contrast you can pull the darks down.
Clarity: Adding clarity in the amount of 10 to 20 can help add contrast in the sky and make the stars stick out even more. Don’t over-do the clarity though!!!!
Dehaze: Dehaze can help add contrast to a night sky as well, but it must be used sparingly. Typically an amount of 10 to 20 is plenty.
HSL: Try to get the color of your sky as close to perfect as possible before going into any other editing software. Use the hue, saturation and luminance sliders to try to get the color as even as possible. You my have to push the green hue towards yellow and desaturate it a bit. Sometimes the teal hue needs to be pushed toward blue. If your sensor has bad color noise at high ISO you may have to adjust the hue and saturation sliders of purple and magenta too.
NOTE: Each time you shoot, the color of the sky will be slightly different depending on the available light, atmospheric conditions and light pollution.
Noise Reduction: It is best to move the luminance noise reduction slider to somewhere around 10 or 15 if you are not going to do noise reduction in an external photo stacking application. The detail and contrast sliders can typically be left alone.
Lens Corrections: In the Lens corrections tab, check “Remove Chromatic Aberrations”. You may also want to check “Enable Profile Corrections” to remove lens distortions. Profile corrections will often add too much noise when the software tries to remove the natural vignette of the lens though. For this reason you’ll most likely want to drag the "Vignetting Slider" to the left to bring back some, if not all of the natural vignette.
How To Edit Star Trail Photographs Using Lightroom And Photoshop
1. Using Lightroom, process the first file in your star trail sequence. Once one image is edited you will have to sync those edits with the rest of the images in the sequence. To sync your settings, make sure the image that you just edited is selected in the filmstrip, then shift click on the last photo in the sequence and click the sync button in the lower right hand corner of the Develop Module. Click check all in the dialog box and hit Synchronize
2. Make sure all of your star trail images are still selected. If they are not, select all photos in the sequence by clicking on the first star trail image in the filmstrip and shift clicking on the last star trail image. Control Click (MAC) or Right Click (PC) on any one of the images in the star trail sequence and choose Edit in > Open as Layers in Photoshop.
3. Photoshop will take a moment to load all of the layers so be patient. Once Photoshop has completely loaded. Select all of the layers in the Layers Window by clicking on the top layer and then shift click on the bottom layer.
4. With all of the layers selected, change the blend mode to lighten. This will cause the lightest pixels to come to the top of the stack resulting in star trails.
5. If there are trails from airplanes you will first have to figure out what layers contain the airplane. Turn each layer on and off to see if any of the airplane trails disappear. When you see a trail disappear, add a layer mask to that layer and paint black with a small brush over the trails. Repeat these steps until all of the airplanes are gone. If you are unfamiliar with layer masking in Photoshop watch my "Layer Mask 101" and "Advanced Layer Masking" videos on Youtube.
TIP: Paint a straight line in Photoshop by clicking at the start of a trail and shift clicking at the end of it.
BONUS: How to create comet star trails in Photoshop. (Tapered stars). Count the number of star trails layers that you have loaded into Photoshop. Then divide 100 by the number of layers that you have. The number that you get will be the amount of opacity that you have to subtract from each layer. Example: 100 / 10 = X (10 in this case) The opacity of the top layer will be 100 then subtract (X) from the layer just below it. So your second highest layer is now 90% opacity in this example. Subtract (X) from 90% and we get 80% for the third highest layer. Keep subtracting (X) from the opacity of the layer just above until you reach the bottom of the layer stack. When you’re done, you’ll have a nice set of star trail comets.
TIP: You can reverse the direction of the comets (Counter Clockwise) by starting at the bottom of the stack and working your way up.
Software Alternative To Photoshop For Star Stacking
StarStax is a free star trail assembler available for Mac and PC. It allows users to easily create star trails without going into Photoshop. The software also allows users to create tapered trails (comets) and fill in trail gaps. On the downside, it does not allow users to remove airplanes and satellites.
Shooting at night can be an exciting endeavor, but if you’re not prepared it can turn into a headache real quick. If you have read this night photography guide in its entirety, congratulations! You’re now ready to go out into the night and create some incredible images. I highly recommend watching the “How to Shoot and Process Star Trail Photos” video to drive these concepts home.
Thanks for reading! Hope to see you in the field some time!