The mechanism behind Move Shoot Move star tracker:
We know our Earth rotates once every 23h 56m4s. Its rotation axis goes through Polaris, and stars are not stationary relative to our Earth.
Just as the below photo shows, the stars circle around Polaris.
According to the 500 rule, we usually can not expose for more than 25s, often less than15 seconds, which results in:
1. Many faint stars are missing from our photo.
2. Ugly stars trails.
3. Noise ruins our composition.
- How to expose more than 60 seconds?
The Move Shoot Move tracker rotates at the same speed as the Earth but in the opposite direction. As a result, the stars will be tracked, and they will remain in the viewfinder. Your exposure time can be up to minutes in duration, faint stars will show up in your pictures, star trails will disappear, and lower ISO helps to reduce noise. Finally, you can get clear, pinpoint photos of stars and the night sky.
The Earth's rotation axis goes almost exactly through Polaris.
So, we need to make the Rotator's rotational axis parallel to the Earth's rotation axis. This is called polar alignment.
- Is your Polar alignment difficult and complicated?
What if I don't know RA, D-dec, and I've never studied astronomy? Can I still do polar alignment?
Don't worry, it's easy-
- If you already know where to find Polaris, then just aim the laser at Polaris, and polar alignment is accomplished😉.
- If you don't know where to find Polaris, then download a free app, 'Skysafari,' set it to VR mode. It will spot Polaris when you move your phone around the sky.
- How to do a polar alignment in the Southern Hemisphere?
- If the star is tracked, will the foreground be blurred?
Yes, the foreground will be blurred. Then what do I do about that? Change the shooting sequence.
- First, we turn the tracker OFF to get a clear foreground shot(your composition).
- Then we wait for the ideal stars to show up in our composition, turn the tracker ON, and shoot the tracked stars. Then combine these two pictures to get the final one in Photoshop or other post-processing software.