In any Astrophotography it is vital to have a sharp of stars as you can to make any details in the night sky stand out since the earth is rotating its motion under the stars gives the appearance that the starts are moving across the sky.

The speed at which the sky rotates is an obstacle for photographers because when you use longer shutter speeds the movement becomes apparent and the stars turn from specs to streak, the longer the focal length of the lens the smaller the region of the night sky you’ll be photographing and thus the movement of the stars will be more pronounced this results in the need to use shorter shutter speeds. This calculation for this maximum to retain sharp stars can be found using Shutter Speed Calculator.

Shutter speed calculator uses the “500 rule” and “NPF rule” to help you to calculate the maximum shutter speed.

NPF rule is more sophisticated way to calculate the maximum shutter speed buts gives the best result.

You cannot take photos using the mobile application, this application only assist you in calculating the maximum shutter speed.

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