This is a composite of more than 300 Creative Commons JPG and PNG images from the internet, from close to 200 amateur astronomers using very different telescopes. No professional data was used.

I lost track of the exposure time on my way, but I estimate it to be close to 1000 hours, based on an average of 50 random samples.

The seperate images vary a lot with regards to resolution, exposure and color, so I took a different approach with this one than I normally do with Crowd Imaging.

First I registered and integrated all images. I used the Robert Gendlers Subaru image as a Transform Master (Gendler's/Subaru's data was not used in the composite). That gave me the possibility to blink my final image against Gendler's/Subaru's, to check wether details were due to noise or real varying star density in the galaxy.

What looks like noise here is actually stars. That goes for M110 and M32 as well.

The integration of all images weighted 1:1 was used as RGB. Next I sorted the sharpest half of the registered images and the half with best SNR. The two stacks were combined into a L layer using luminance and wavelet masks. The L layer was then processed using several layers of Deconvolution, again using different wavelet masks, Morphological Transforms, different sharpen filters, a slight HDR adjustment, etc.

Finally the L layer and the RGB layer was combined into a LRGB image. Notice that I didn't change colors in the RGB layer, as the Crowd imaging method gives a very good color fidelity.

All processing was done in PixInsight. Everything was done in 100 Mpix resolution, and scaled down to the 36 Mpix version shown here. I started over several times and spent close to a month making the image.

I enjoyed the process very much, learned a lot about M31 and I think this method has great possibilities, especially with even more data and faster computers in the future.

I hope you like it.

Clear Skies

Morten :)

PS. I know the field is pretty deep, and there are a lot of quasars in there, but I haven't found out how to measure magnitude of the faintest stars, since the image isn't linear data. If anyone knows a way, please let me know.

PPS. For more description on the Crowd Imaging method, read the text for the M42 Crowd Image I recently uploaded, or fell free to ask!

http://www.astrobin.com/119854/

Image credits. Thanks a lot to everyone for sharing your data! I sincerely appreciate your efforts, and the honor of using them:

3p0, achrntatrps, Adam Evans, Ahmed Jaber, Ahmet Kale, aknotwot, Alex Lovell-Troy, Álvaro Pérez Alonso, Alvinillo, Andolfato, Andrea Tosatto, Angel Requena, Antonio Ferretti , äquinoktium, arcturus13, Asaf Braverman, astrojeff, Astroluc63, Bas Witkop, bbrowning, Ben Gilsrud, Bob Familiar, Bob Star, Boris Štromar, Brian, Burkhard, buscettn, Carl Drinkwater, Cars10s PhoToes, Carsten Frenzl, Casey Fox, Cestomano, Charlie Prince, Ching-Yun Chen, Chris Isherwood, Chris Lasley, Chris Madson, ckrege, Claustonberry, Cobbler, Cody Garges, Cosmosium, Creedence, Cyrus II, David Evans, David DeHetre, David L Milligan, David Morgan, ddkphotography, Delberson, Denis Santana, Eduardo Mariño, er Guiri, Eric Gorski, Esben Kristensen, Ethan Hein, Evaldas Granickas, Ferran Ginebrosa, Filippos Filippoglou, Flameoffurius, Florian Meyer, fphg, fragro, Fred Locklear, Fredrik Ödling, Gary Gause, gianni, Giuliano Pinazzi, Göran Strand, gulielmus, Gustavo Naharro, Harry Braviner, Heiko Günther, HoangP, Jan Curtis, Jason Ahrns, Javier R., Javier R., jdiwnab, Jelly Dude, Jerome Marot, Jim Mac, John Lanoue, john.purvis, johnny9s, Jorge, Jorge Barata, Jose Carlos Castro, jpstanley, jster91, Juan Lacruz, Juan Lozano, Juan Pacheco Tirado, Jürgen Kemmerer, Jussi Kantola, Justin, Ken_Lord, Kevin Pratt, Konstantinos Stavropoulos, Lars Veldscholte, Lars Veldscholte, Laura Rathbone, LE DALL, lizarranet, Luca Argalia, Lukáš Kalista, Lukáš Kalista, makelessnoise, Manuel Balvin, Marc Van Norden, Marek Isalski, Marius Strom, mariusstrom, Mark Kilner, Mark Philpott, matted69, Matthias, Maxence Régnier, maxou9914, Michael Kalus, Michael Karrer, Mike Durkin, Mike Markiw, Mike Miller, mopar05ram, Morten Balling, Muzzy Hussain, nd-nʎ, Niedzwiadek78, Odd Trondal, Oliver Czernetz, Özgür Ünat, Patrick Denker, Paul M. Hutchinson, PaulHutchinson, Pete Collins, Peterkennett, Philipp Salzgeber, Phototriber, pmonaghan, Ralph W, Richie Jarvis, RIKY, Ro Irving, Rob Glover, Rob Petri, Robert Couse-Baker, roxunreal, s58y, s58y, Salvatore Iovene, Salvopa, samuele, Sendell, Serge, Sergei Golyshev, sergio.diaz, SlyminAP, SlyminAP, smalljude, Stan McQueen, Stan Weber, Stefano Giardinelli, Stephen Rahn, Steve, Steve Yan, stevebryson, Sylvain Billot, Terry Tucker, TheBreed, theilr, Thomas Bresson, Tim, Tino Leichsenring, Tom Fear, Torben Hansen, tonynetone, vetenskapsman, Wendell F. S. Diniz & Yohan Riou.