If this image is part of a "set" for stacking (common in communities like Cloudy Nights ), it is likely a sub-exposure or a calibration frame.

Are you trying to the photo or build something based on what is in it? Do you have the other files in the set (e.g., 2x, 3x)?

: Ensure the clips are spaced according to the visual reference (usually roughly a finger's width from the end caps).