Complex sentence: A dimmer appearance results in less visual detail of the object; matter, rings, spiral arms and gases are some details which may be completely hidden from the observer giving a far less "complete" view of the object or range.
Split into simpler sentences: A dimmer appearance results in less visual detail of the object. Details such as matter, rings, spiral arms, and gases may be completely hidden from the observer, giving a far less "complete" view of the object or range.