Surface brightness of M51

[vlaiv]

Just for those interested, I made an image / diagram or graph (not sure how to call it) that displays approximate surface brightness of M51 in magnitudes - might be useful for anyone trying to figure out needed exposure time to achieve good SNR.

Data is luminance (LPS P2 filter) and roughly calibrated to give mags (it might be off by a bit - I was not overly scientific about it). Calibrated on single mag 12.9 star, median filter used to smooth things out.

Here it is:

Each color is single "step" so cores are at mag 17 or higher and background is at mag27 or darker. Again, this is rough guide