As usual, there were so many nice images here!
There are some really splendid Orion images here. Stefan_S, your NGC 2024 and IC 434 in Ha and OIII bicolor is fascinating. Look at that nebular detail!
Roberto Capacci, your Surroundings of Alnitak image is extremely beautiful to me. The colors! The details! The general loveliness! Aaaahhh! (Tell me, though, are all those little white dots artifacts, or are they in fact itty bitty little stars?)
Massimo Tosco, that's a great Orion complex! I love how you bring out all that dust, and the color difference between the Orion Nebula and the Horsehead region nebulosity. I'm happy to see the Orion's Belt here, too!
And speaking of the dusty structures in the Orion complex, and the color difference between the Orion Nebula and and the Horsehead region, and Orion's Belt to top it all off - Jose Mtanous, that's a magnificent image! The largest version of your image, found on your own homepage, is a stunner. Alnilam, the middle star of Orion's Belt, looks like a fireworks thingie sprinkling smaller stars in all directions out of itself!!
And Greg Parker, your Running Man nebula is nicely captured, too - I think I can see him run!
Finally, George Gajdos, your Orion Rules the Winter is a great image. I love how the sparkles of the icicles compete with the sparkling stars of Orion! (And look at all the nebulosity you have captured for us, too!)
Another "theme" here, although one with only two images, is the Rosette Nebula. Máximo Ruiz, that's a truly lovely Rosette.
And Emil Ivanov, your "Two Rosettes" is wonderful! The lovely little Sh2-170 is a delightful Rosette lookalike, indeed. It is an extremely graceful nebula. However, your image of the "real" Rosette brings out an important detail: a group of sufficiently hot massive stars will clear a significant cavity around themselves. The Rosette Nebula is actually one of the most impressive-looking nebulae in the sky, due to its impressive shape with that cluster in a cavity surrounded by an elegantly round "rosy" emission nebula. (Admittedly the Rosette is not bright enough to compete with nebulae like the Orion Nebula or the Lagoon Nebula.) We can see that Sh2-170, in spite of its loveliness, is no real match for the Rosette. Only one or two hot and massive stars can be seen at the center of it, and the stars have not yet hollowed out an impressive cavity.
Now that I'm looking at images of the Rosette Nebula, I might comment on an image of of "neighbour" of the Rosette, the Cone Nebula and the Christmas Tree cluster. That's a lovely picture of ethereal colors and shapes, Michał Żołnowski.
A very popular theme here is halos, mostly around the Moon. But that's a great Sun halo, Diane McKinney.
Alan C Tough, you have captured a fine "beige but softly iridescent" Moon halo, with Orion on the left and bright Jupiter at four o'clock.
Tamás Ladányi, you have captured a very blue Moon halo, again with a bright Jupiter at four o'clock. That's a great castle!
Petr Horalek, your Moon image is fantastic! The Moon itself is sharply detailed, and the Lady in the Moon is extremely obvious. And the corona around the Moon is marvellous! Talk about a feast of colors!
I think that, after all, Patrick + Selina Hochleitner's 22°Lunar Halo in the Alps is my favorite. I love the brilliantly clear starscape behind the lunar halo. The star colors are fantastic, given how the lunar halo must have washed out the sky. You can clearly see that most stars here are blue, but that Betelgeuse is yellow and Capella is white, and you can clearly see that Pollux and Castor are different colors. And you can spot a faint reddish tint in the lunar halo which contrasts with the Moon-illuminated dark blue night sky. The mountains impart dramatic structure to the picture, too. What an image!
And now I'll stop trying to create "themes" and just comment on images. Stephane Vetter, I may have seen your Milky Way over the Matterhorn image before, but it is still an absolute stunner.
Geert Vanhauwaert, I don't have to tell you that I love your Color contrast in Vela image, do I? You sure know how to tickle the astroimage color nerd in me!
George Kristiansen, I really like your Belt of Venus over the Atlantic. My favorite part of your image is the complete magic of that colorful Union Jack bit of an airplane wing. You picture reminds me of the wonder of the fact that humanity can fly, even if it takes us airplanes to do it.
Adam Block, your LBN 1022 in Monoceros contains some fantastic nebular ghost-like dust shapes, haunting a delightful and colorful starscape.
M. Raşid Tuğral, I really like your picture, and even more when I read the caption: Capadocia under the Rain of Stars. Those little fairy chimneys (hoodoos) look amazing, like they were taken out of a fairy tale or a fantasy land. I'm reminded of the popular myth of Saint George and the Dragon, too. I distinctly remember that at least one version of this myth claimed that the famous knight was from Capadocia!
Scott Rosen, I like your Silver Dollar Galaxy in Sculptor.
Angus Lau, I just love your NGC 1097 image! This is a great galaxy, and it doesn't get photographed so often. Your image brings out absolutely fantastic detail. Look at that great oval yellow bar-bulge with those very distinctive dust lanes running through it. Note how there appears to be star formation at the outer ends of both long dust lanes. Note the extremely bright white ring surrounding the nucleus, the remnant of an incredible burst of circumnuclear star formation. Note the bluish ring surrounding the large yellow bar-bulge, and note the two long bluish arms. Note how one arm is interacting with a small white oblong dwarf galaxy. So indeed, Angus Lau, this is a fantastic image!
There are many other fine images here, but I don't have time to comment on the others. Thanks to everyone who submitted images here!