I have yet to see a technically well-done astronomical photograph which is ugly. I have seen ones that are ugly because they have been technically poorly done—indeed, most of my own photographs other than of the moon have ranged from ugly to boring, but this is a function of technical inaccuracy (out of focus, not long enough exposure, lack of tracking, etc.) rather than of any ugliness in the subject. It appears that astronomical objects range from neutral to beautiful.
Astronomical objects are not alone in this. In fact, there are very few if any natural, inorganic objects (crystals, mountains, clouds, waves, etc.) that are ugly, and many that are beautiful. It is only within the realm of man-made, biological or formerly biological objects that we find ugliness. Buildings, paintings, musical compositions, bugs, body parts, and corpses can all appear ugly to us. But even there, we might want to make a few distinctions. It is not clear that any normally functioning biological organism, or even a part thereof, is properly seen as ugly. There is some plausibility to the idea that if I were to devote my life to study of the world's ugliest sea creatures, I would cease to see them as ugly, and I would be right so to cease. So it could, in fact, be the case that in the biological arena, it is only the abnormal biological organisms, their current parts and former parts, and their corpses that should be seen as ugly.
It is plausible, then, that beauty by far predominates over ugliness in the universe, and indeed I do not know of anything ugly outside of the earth and things originating from the earth (maybe there is an ugly painting on board the ISS). This is an interesting aesthetic asymmetry. Moreover, it calls out for an explanation. (It will not surprise anyone that I would hope for a theistic one here.)
An interesting topic for discussion would be classes of objects that appear to have no ugly instances. I am not sure I've seen an ugly healthy tree, or an ugly healthy flower (though some have an ugly smell).