I wish to introduce to your attention this picture, that you can see at the
following link:
http://www.danilopivato.com/tabulae_coeli/1900_s30/m17_brc_ha_new.htm
Showing:
M17 Omega Nebula
Technical data: BRC250 F/1268 + ST10XME * filter H-alpha 6,3nm
Exposed 5x1800 seconds in mountain 1550m (Forca Canapine - Italy)
Below the icon image for link to pixel real I left link for the old
photo at the M17, made by the Rome sky with filter H-alpha 3nm
Regards
Danilo Pivato
www.danilopivato.com