Nice shot !
Here is mine with similar equipment as you have (Coro90,ASI174MM)http://sweiller.free.fr/AstroMovies/AM-Mercury.html
Nice. I'm impressed! How did you get the color in? I reprocessed one and used Split toning in ACR (Adobe Camera Raw) to add some color to mine.
This one was stacked in AstroStakkert 2.6 and processed in Pixinsight.
I notice some banding in my image, and am wondering if it's from the camera, over processing, or converting to JPG. Or something else. I see them as Vertical bands, and I think I need to rotate the image. But over all I'm happy with it.