Where information on the photo is available, a description will be listed for that photo.  This may include information regarding which film was used, which instruments were used to take the photograph, the focal length, and the duration of the exposure.   

After studying the film types listed by astrophotographers, you may find a preference in film background coloration or clarity as a reference if you want to engage in this rewarding hobby.  You might also make note of the various techniques used and the various optical instruments and accessories that are used to get various types of photos.

For more information visit Beginning Astrophotography.