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Data from mtfreestyler on reddit astrophotography:
https://www.reddit.com/r/astrophotography/comments/5qs9hj/eta_carinae_nebula_ngc3372_taken_15_hours_drive/
The image is is copyright mtfreestyler.

Processing:

Followed: Astrophotography Image Processing Basic Work Flow

Raw convert with lens profile (just selected Canon 600 f/4 (looked like a good match) to reduce light fall-off), daylight white balance.
(This took ~2 minutes of my time, 20 minutes on my old computer to compute.)

No darks, no flats, no bias.

Stacked in DSS. No calibration selected, Save DSS stack result as 16-bit tif with embed stretch but do not apply.
(This took less than 1 minute of my time, more than 1 hour on my old computer to compute.)

Crop off the edges from the DSS stack.
(This took less than 1 minute of my time.)

rnc-color-stretch: rootpower = 12, scurve1
(This took less than 1 minute of my time, 32 minutes on my old computer to compute.)

Star reduce size in imagesplus (default settings). (This took less than 1 minutes of my time, less than one minute on my old computer to compute.)

Final tweaks with curves in photoshop (slight contrast boost in brighter areas), blur brightest saturated stars. (5 minutes of my time.)

Result (~10 minutes of my time):