From Neptune, the Sun appears significantly dimmer compared to how it appears from Earth. Neptune is the eighth and farthest known planet from the Sun in our solar system, so its distance from the Sun is quite substantial. The average distance between Neptune and the Sun is about 4.5 billion kilometers (2.8 billion miles).
The intensity of sunlight decreases with the square of the distance from the source. Since Neptune is about 30 times farther from the Sun than Earth, the amount of sunlight reaching Neptune is approximately 1/900th (30 squared) of the intensity experienced on Earth.
To put it into perspective, the Sun's brightness from Neptune is approximately 900 times dimmer than it appears from Earth. Therefore, the Sun would be significantly less bright and appear more like a distant star from the vantage point of Neptune.