The Jones-Emberson collaboration gave me an idea.

This is an image made by combining all the M42 images I could find with a Creative Commons license. More than 100 jpg images were combined using PixInsight, and processed into a single 64 bit image.

The method gives exceptional SNR, and therefore processing allows heavy filtering, like deconvolution, HDR etc. without introducing noise. I haven't calculated the total exposure time, but a guess is around 500 hours.

All images are weighted equally. Therefore every little error in the original images are minimized, because each image contribute about one percent to the final result. At the edges of the image I have less coverage, and therefore a little bit of noise etc.

Another interesting side effect is that the colors are very "true" as well. Two separate stacks of half the images (55 in each), render very similar results and colors. This is due to all the different participants interpretations being averaged, but common preferences will show through the method.

Both monochrome and color images were used.

Thanks to all the people who share their data. You rock!

Clear Skies

Morten

PS. I've tried the method several times now, with up to 500 images while testing. It seems that 50 images gives a good result, 100 is optimal, but 500 gives a deep exposure.

PPS. Share your data. Change your license to CC (Attribution-NonCommercial-ShareAlike) so your hard telescope work can flourish. Thanks :)

Image credit:

Adam Block, Adam Evans, Ahmet Kale, aknotwot, Alizée Rait, Álvaro Pérez Alonso, Alvinillo, Andolfato, André Lucas Melo, Andrew Bennett, Angel Requena, arcturus13, astrojeff, Barry Brook, bbrowning, Bob ten Berge, budman1961, Casey Fox, Charlie Prince, Chris Madson, Chris Ryan, ckrege, Claustonberry, Cody Garges, cristiano.c, Czerwik, David Milligan, David Nguyen, deadlydude, dgc, Eric Kallgren, Filippos Filippoglou, Flavastro, fragro, Fredrik Ödling, Gary Gause, geco71, gulielmus, Gustavo Naharro, harbinjer, Heiko Günther, homer2jedi, Igor Fulvi, J.Mattei, Jan Curtis, Javier R., Jay, jdiwnab, Jeff Tropeano, Jorge Barata, Jorge Gomez, José Luis Márquez Regueiro, Juan Lozano, Jussi, Kantola, Konstantinos Stavropoulos, LE DALL, Luca Billeri, m_abdulkareem, MacRoAstro, Marcelo Domingues, Matthew, maxgaspa, Mikko Laine, milosz, mondoman712, Morten Balling, Nathan Coleman, nicoairbus, P. Fred, pascvale13, Paul Storey, PaulHutchinson, PoGo, psoup487, Ramon, Richard Muhlack, rid, RIKY, Rowland, Ryan Shaw, Salvopa, Sebastiano Recupero, Shane Poage, sipa, smithy, Stan McQueen, Stefano Giardinelli, Stefano Morandi, Steve, Steve Yan, Surfus_1980, sweeper, TheBreed, TimN, Tino Leichsenring, tphelan88 & Yohan Riou.