Technical Card
Date:	Oct. - Nov., 2024
Location:	Various
Camera:	Canon T7i
Lenses:	Various
Software:	StarStaX, MS Photo

Fall 2024 - Star Trails

Star trail images aim to catch the movement of stars across the night sky through the use of photos with long exposure times. From our perspective, stars appear to slowly move across the night sky from east to west because of the rotation of the Earth in the same way that our star, the sun, appears to move across the sky from east to west during the day. Capturing these star trails is relatively easy and can result in very scenic shots.

Setting a camera (usually a DSLR) on a tripod, you take a continuous series of images, usually 30 seconds each (which is the max for the average DSLR). While the camera shutter may only be open for 30 seconds, this is enough for all the stars to appear to move slightly. Thus, each 30 second image captures a short section of each star's path across the sky. These shorter exposures are then added together using special software to produce what is effectively a single image showing the stars' trails over a few hours. (Note: Foreground objects do not produce trails as they are not moving relative to the camera.)

Because such image sequences are simple to take, we simply set the camera going to take repeated exposures, and then came back an hour or two later to retrieve it.

Click on the thumbnails below to see larger versions of the final images that were created from our different nights of imaging. (Individual attributions refer only to post-processing.)

This image was created by pointing a camera at the North Celestial Pole (NCP) and capturing 192 consecutive images. The images were then put together using software called StarStaX. Because we captured so many images we are able to see the Earth’s rotation which is centered about the NCP. This process created the star trails you see in this image. Slightly offset from the center to the lower left is the north star, Polaris, which is very close to the Celestial Pole.
If you look carefully you can see some plane and satellite trials, and even a small meteor, cutting across the star trails.

Pointing at the North Celestial Pole
(Emma Krebs)

This image was created by combining nearly 200 images in a program called StarStax as well as adding dark frames in to the edit. We just used a regular camera with a longer exposure time to catch the stars moving through the sky. The program then combines the brightest pixels in the images together for the final product. This specific photo is looking towards the north-eastern part of the sky. It is interesting to note how the trails make it easier to distinguish the various star colors.

Trails in the north-eastern sky
(Austin Niec)

The images used for this Star Trail images were taken on November 17th, 2024. A total of 151 images were in this set. Star Trails are made by pointing a telescope at a section of the night sky, keeping it in that position, and taking a set of pictures. Exposure time can vary, but for this set it was 30 seconds each. All 151 frames were then loaded into StarStax, an astrophotography software, and stacked together to form the star trails. There was an option to use an additional Master Dark Frame to eliminate any hot pixels, which are pixels that just get excited in the readout process. However, the hot pixels that appear don’t affect the image too much, so I decided to leave it as is.

Southern sky trails through the trees
(Emily Vaughn)

Technical Card

Fall 2024 - Star Trails