Milky Way Time-lapse with Smartphone

If a smartphone is able to shoot Milky Way images, why not the Milky Way time-lapse. Creating Milky Way time-lapse on smartphones involves a lot of post-processing to edit all the frames and render the frames into video format. One important tool for shooting time-lapse is intervalometer that takes photos automatically in every user-defined time interval. It can be hardware or software intervalometer as long as it does the job.

SETUP : Intervalometer

Option 1 : Intervalometer. Intervalometer is an automated Android app to trigger camera shutter with a self-configured timed interval. Normal time-lapse mode in most smartphones only allows auto exposure without additional controls on exposure settings and RAW format. This app works like an actual intervalometer for smartphones, it automates camera shutter triggering and it works on any camera app. Check full description here.

Option 2 : Camera FV-5 app (paid app). The camera setting on shooting time-lapse is similar with shooting Milky Way images except that we need intervalometer. For smartphones, there are plenty of time-lapse apps but most of them don’t support long exposure timelapse with RAW format. Camera FV-5 is one of the apps that gives full control on the camera including configuration of intervalometer. After setting proper exposure, start the intervalometer to start capturing every time-lapse frame in RAW.

Option 3 : Using Android ADB command (need a computer). There is a requirement for using this method – shutter button must be able to be triggered by volume buttons. In many smartphones, volume buttons act as shutter button when camera app is opened, this feature allows us to setup an intervalometer by triggering volume button automatically. However, this requires a computer with Android ADB tools installed (download link). On phone’s setting, enable USB debugging.

On PC, open command prompt and navigate to ADB directory that contains “adb.exe” file.

  1. Connect both phone and computer to the same network.
  2. Connect phone to computer with USB cable and type “adb devices” in the command prompt windows to check whether the phone is connected.
  3. Enter “adb tcpip 5555”
  4. Disconnect your phone by unplugging the USB cable
  5. Enter “adb connect <IP address>:5555”
    • IP address can be found in Setting > About Phone > Status > IP address
    • e.g. “adb connect 192.168.71.100:5555”
  6. Enter “adb devices” again to make sure it is connected.
  7. Enter “adb shell”
  8. Open Camera app in phone and setup the tripod. This is the command for configuring time-lapse.
for i in `seq 1 <no. of frames>`; do input keyevent 24; sleep <time interval between each trigger>;done
    • 24 and 25 are the values for triggering volume up and volume down action.
    • e.g.
for i in `seq 1 90`; do input keyevent 24; sleep 31;done

This command will trigger camera shutter 90 times(frames) with interval of 31 seconds between each trigger. 31 seconds is the sum of 30 seconds shutter time for each shot and 1 second buffer time for it to save the RAW image.

Option 4 (not recommended) : Connect earphones and trigger shutter button by pressing volume button on earphones manually for all the frames.

POST-PROCESSING the frames

Software needed:

  1. Adobe Lightroom
  2. LRTimelapse

Adobe Lightroom and LRTimelapse work well together in editing and ramping exposure on each frame to smoothen exposure transition from beginning frame to ending frame. These 2 software are enough from post-editing to rendering final time-lapse video. Here is a guide that provides clear explanation on using LRTimelapse.

 

Creating lower noise Milky Way time-lapse (Deep Sky Stacker)

Each frame of the time lapse is a single exposure image from smartphone, there will be a lot of noise. To create a cleaner Milky Way time lapse, I used image stacking on every frame by just sacrificing last 3 frames. This process is very time consuming.

In DeepSkyStacker, open all frames as light frames.

  1. Check 1st 4 light frames, set the 1st frame as reference frame (right click on 1st frame > Use as reference frame) and stack 1st, 2nd, 3rd and 4th frames together to create 1st stacked output frame.
  2. Uncheck 1st frame, check 2nd to 5th light frame, set the 2nd frame as reference frame and stack 2nd, 3rd, 4th and 5th frames together to create 2nd stacked output frame.
  3. Uncheck 2nd frame, check 3rd to 6th light frame, set the 3rd frame as reference frame and stack 3rd, 4th, 5th and 6th frames together to create 3rd stacked output frame.
  4. Continue until last 4 frames are used to create the last stacked output frame.

For a total of 90 frames, it will end up with 87 stacked frames because last 3 frames will be used to stack with 87th frame. Every output frame is now a stacked of 4 frames which means the noise level is reduced by half and this allows us to edit to further extend in Lightroom. Since the stars are aligned for stacking, foreground will be misaligned and blurry but with just 4 frames and each frame will be down-sampled to video resolution (1440p or 1080p based on your preference), blurry effect wouldn’t be obvious.

By importing all the stacked output frames to Lightroom, similar steps on LRTimelapse and Lightroom can be performed to render a lower noise Milky Way time-lapse.

 

Going Further

1) Image stacking for better quality Milky Way image. The images can be reused to create a cleaner stacked Milky Way image.


The Photographers Guide to Image Sharpening in Lightroom: Professional Image Sharpening & Noise Reduction Techniques using Adobe Lightroom

2) Star trails time-lapse

Other than creating Milky Way time-lapse, the frames can be reused to create star trails time-lapse. StarStax is an application to create star trails images easily. Similar to my previous post in creating star trails time-lapse, but every step needs to be saved when StarStaX is stacking the images. There is a “Cumulative Image Saving” option in Preferences that allows us to saving every frame of star trails.

3) Comet-mode star trails time-lapse (check Comet Mode option box in Preferences)

Creating time-lapse video is a time consuming and processor intensive work for computer, but once we get familiar with the workflow it will not be a painful work.

4) Final time-lapse : Combine all the time-lapses into a single video and add a soundtrack with Adobe Premiere Pro.