Detailed explanation of shooting method of stellar orbit

Attention should be paid to the environment, exposure, focusing, shooting direction, shooting time and other issues in star orbit shooting.

1 environment

Conventional starry sky photography needs to go to a place with less light pollution, usually dozens or hundreds of kilometers away from big cities. Orbital photography can be taken in cities. In the environment with low light damage, the photographed star orbits are dense, while in the area with high light damage, the photographed star orbits are sparse. You can shoot even in urban areas. Try to avoid strong light sources when shooting, and never face the light sources directly.

Step 2 expose

There is no exact exposure value. According to a principle: under the premise of not overexposure, try to increase the exposure (you can capture more stars). The stars will move. When it moves, the exposure of the shutter cannot be accumulated. Therefore, when increasing the exposure, we should give priority to increasing the aperture and sensitivity, and then the shutter. But you can't improve the sensitivity indefinitely, which will reduce the image quality.

? Step 3 focus

Never let the stars become empty. It is popular on the Internet to "twist the focus ring to infinity and turn it back a little", which is not reliable. You first adjust the focal length to MF, then find a bright star, then zoom in, and then turn the focus ring, and the star becomes a real point.

4. Shooting direction

The exposure is adjusted and the focus is on. Let's start shooting. Determine the direction before shooting. The earth rotates, and now Polaris is very close to true north. It is almost on the extension line of the earth's rotation axis, and you will see all the stars revolve around Polaris. Facing Polaris, the orbit is round. Facing due south, it is curved. Facing east and west, with vertical lines or diagonal lines.

5. Blasting time

The star rotates once every 24 hours, which is 360 degrees. Is there any objection to this? Knowing the rotation angle of the star and the distance from the center of the circle, we can calculate how long this orbit is. If you can't imagine it, just find a piece of paper and draw a picture. In fact, it doesn't have to take 24 hours to see a circle, because there are many stars, and each star has a cross section, which adds up to a circle. (It is also impossible to shoot 24 hours a day, and it will not be filmed at dawn. )

6. Post-processing

Open ps, select File-Script-Load File into Stack, and select all the photos taken. So every photo is a layer. Then select all layers, right-click, and turn them into smart objects. Then it will become a layer. Then choose Layer-Smart Object-Stacking Mode-Maximum. The star track will appear, and then you can adjust the color, exposure and sharpening.