[Weltevreden SA (Dana)]

Steven, you mentioned boosting the SII emissions relative to Ha as part of the science goal of the image. Was this goal to probe the SI column density [logN(SI) is 16.3/sq.cm in the Hourglass] as a gauge of emission intensity from the Her36? Garnett 1989 suggests that the N(SII)/N(SI) ratio is >3 for many Galactic cluster forming regions. It seems upon eyeball inspection that emission intensity is little different in the Hourglass core but discernibly brighter & more textured in the structures illuminated by Sgr9 (O4), esp the filaments N of the HG. The Teff of O7.5 Her36 is 36,000 K while O4 Sgr9 is 42,000 K. Her36 itself is reddened by 6.3 Mv by a local superimposed dust remnant but the Hourglass as a whole is only ~1.7. IOW, the added UV intensity produced by 6,000 K can be revealed by astute line selection in image processing. Was your goal to demonstrate this is the kind of science that can be drawn out of image processing available to most enthusiast budgets? If so, good show! =Dana in S Africa