What are the consequences of choosing a larger exposure index, sensitivity and iso for celestial photography?

Choosing a higher camera sensitivity ISO will lead to increased noise, poor image quality, overexposure and reduced dynamic range.

Noise increase: High ISO will increase the noise of the camera sensor, thus making the image blurred and grainy, especially in dark areas.

2, poor image quality: high ISO will make the details and color information of the image lose, resulting in poor image quality.

3. overexposure: If the ISO setting is too high, it will lead to overexposure and make the image lose details and layering.

4. Reduced dynamic range: A high ISO will reduce the dynamic range of the camera and reduce the detail expression ability of the light and dark parts.