Knowing your astrophotography setup's pixel scale will help you take better pictures. And to determine pixel scale, you first need to know your field of view.
Good weather for imaging is about more than just the clouds! Even if it's cloud-free, you'll need to understand if the seeing and transparency are good.
Astrophotographer Richard S. Wright, Jr. embarks on his imaging blog. Join him each month to learn how to get the most out of your imaging equipment.