SH2-240 is a very large (approx 3x3 degrees) and dim supernova remnant on the Taurus/Auriga border.
We captured 63 hours of Ha data on this object back in late 2014/early 2015 at SRO (California) as a 3x3 mosaic with a FSQ106ED and QSI683 camera (2x2 binning). Unfortunately, we were too late to capture enough RGB to make a full colour image so I have been sitting on the data for a while. Then, in late 2016/early 2017 we captured 19 hours of Ha/R/G/B with a Rokinon 135mm f/2 lens at DSW (New Mexico) which included the original field of view. This is my first attempt to combine the data using the Rokinon wide field as a base. My next project is to make a high res version based on the SRO data with the DSW star colours.
DSW data capture details...
Scope: Rokinon 135mm f/2
Mount: Paramount ME
Camera: QSI583
Filters: Astrodon E-series Gen II LRGB, 5nm Ha
Image scale: 8.6 arcsec/pixel (drizzle to 4.3 arcsec/pixel)
Exposures: 24x300s R, 21x300s G, 27x300s B, 78x600s H (19 hours)
SRO data capture details...
Scope: FSQ-106ED
Mount: Paramount ME
Camera: QSI683
Filters: Astrodon 5nm Ha
Guiding: QSI OAG + Lodestar
Image scale: 4.19 arcsec/pixel
Exposures (3x3 mosaic):
A1: 16x1800s Ha
A2: 16x1800s Ha
A3: 13x1800s Ha
A4: 15x1800s Ha
A5: 07x1800s Ha
A6: 10x1800s Ha
A7: 19x1800s Ha
A8: 19x1800s Ha
A9: 11x1800s Ha
All image processing done in PixInsight. I'm still not sure if the result is just too red

I'm having some colour management issues that are proving difficult to diagnose.
Higher res version at Astrobin:
http://www.astrobin.com/full/284525/0/
Thanks for looking and for any constructive comments.
Cheers,
Rick.