Shooting Star Trails

Have you ever seen a photograph where it looks like the stars revolve around a landscape or an object ?

You probably think that the photo is completely manipulated and is impossible to photograph this phenomenon.

Today I'm going to show you that is real and anyone can capture the movement of the stars (or the earth), although in some cases you do require the intervention of a software like Photoshop, its only function is to fuse the different images to complete the effect.

The trick is to find the North Star, as the earth revolves around the sun on an imaginary axis, which points north. Therefore if we point our camera at the North Star, we get a visual of the stars rotating around the earth, but really it is the earth that is spinning.

Step 1: Gear

First, you will need the following

- Camera with "BULB" mode.
- Tripod.
- Remote or cable release.
- Optional: iOS or Android Application that allows finding the location of the pole star.
- Photoshop
- A lot of Patience.

Step 2: Find the Right Place

First, in order for your photograph to be successful, you have to plan it in advance. During the day, look for a place that is preferably away from the city, since we don't want any light pollution that can compromise our photo.

Step 3: Prepare Your Equipment Properly

I recommend to do this under the moonlight as this can help illuminate your subject or landscape without over exposing the stars (depending where you point your camera). Arrange your camera on your tripod and make some test shots. Normally you wont see anything using the "view finder" so you'll have to do your test shots with high ISO and the maximum aperture of your lens. When you have the desired composition, adjust your ISO and aperture to achieve the desired sharpness. In these low-light, auto focus is practically impossible, so you will have to focus in manual mode, or by lighting up your target with a flashlight to focus.

Mixing variables ISO, aperture and shutter speed, change your exposure to achieve the desired effect, remember that what we are looking for is to trace the trail of the stars to earth movement. For example, when we take a photograph in the city during the night and leave our aperture open for a few seconds, we can see how cars trace a line of very interesting colors, we apply this same concept here, but with much longer exposure.

Step 4: Get Ready to Shoot

When you're ready to start your shots, make sure your camera is completely stable in its tripod, use a remote shutter release as this will help the camera to keep completely stable and not ruin your composition. Preferably use a control that allows you to define the number of shots you want to do under the same variables as this will not interrupt the cycle of the movement and the effect of the stars will be more fluid and natural. Turn all the lights off and start shooting.

In my first image, the settings I used were ISO 400, f5.6 and an exposure duration of 5 minutes. Here we can see how the stars are beginning to give a motion effect.

My first image will be my main photo  and the rest will only be used to merge the movement of the stars. For the final result, I took 24 photographs, all with ISO 400, f5.6, with 3 minutes exposure, giving a total of 74 minutes of total exposure.

You can take a look at some of the different photos I took, they probably look the same at first sight, but if you look closer, you will note that the stars are in a different position.

Step 5: Blending Our Photographs Together

Our final step is to take our photographs to Photoshop, all you need to do is blend the images together by using the "Lighten" blending mode, put the layers on top of each other and change the blending mode to lighten ("Aclarar" in spanish).

Step 6: Final Result

This is the final result, we are finally done, as you can see it's really not that hard but it takes some time so you need to be very patient, I hope you find this step by step tutorial helpful.