In order to help demonstrate that this form of Venus "ashen light" isn't hardly of earthshine, but certainly could have been artificially produced, I've run off some preliminary numbers that shouldn't surprise you, unless you're as thoroughly snookered and thereby as dumbfounded as most Americans, especially of those of our pro-Apollo or bust cult, and as such I'm reasonably certain that your math is even better than mine, as well as for uncovering the capable candela capability of xenon/mercury lighting cannons that could more than accommodate the task at hand.
Just for argument sake; if we'd started out with using a 500 meter diameter worth of illumination source, and if that source were initially focused to 1°, this is what we should expect such technology application to obtain as for transmitting into and subsequently getting photons through those clouds.
Illumination source elevation: 5 km
Illumination source diameter: 500 meters
Raw illumination divergence: 1°
Cloud bottom elevation at roughly: 50 km
Cloud density/thickness: 20 km
Illuminated zone/diameter upon cloud bottom: 1.286 km
Illuminated zone/diameter upon cloud tops:
At zero further divergence: 1.635 km
At +/- 45° divergence: 12 km
At +/- 60° divergence: 19 km
At +/- 75° divergence: 39 km
At +/- 80° divergence: 58 km
At +/- 85° divergence: 110 km
At +/- 90° divergence: 499 km
At a cloud plus haze depth of 25 km, it may take the +/- 85° through-pass divergence in order to obtain the exit illumination of 500 km diameter, such as that illumination viewed within the "heath4.jpg".
This is where physics-101 or perhaps physics duh-101 comes into account, in that I'd previously estimated upon the illuminated zone of the heath4.jpg (by; Alan HEATH [Nottingham,UK]) as being 500 km in diameter, and now that I've applied some further math in order to best identify what a reasonably focused beam of xenon/mercury photons striking the bottom of them clouds might have, this is in fact diffused out to that zone of perhaps at most 500 km, that is unless the originating source were of an even larger diameter and/or of greater divergence to start off with.
Surely a smaller and more focused beam would only improve upon reducing the exit illumination zone, whereas cloud and haze depth are of the primary divergence factors, then of cloud elevation and/or source distance from the cloud base being second. The nighttime clouds should be at least 10% lower than by day, and perhaps 20% thinner, as such the nighttime season of cloud illuminations should be offering a somewhat smaller diameter, perhaps as little as 50% the daytime illumination if generated by the same source, although the nighttime illumination energy should require but 10% of creating a daytime event.
The maximum parabolic diameter that I might otherwise suggest upon is 1000 meters, although that only adds another 0.5 km factor into the overall end result, which is merely a 0.1% shift. Thereby a larger diameter of source might only be necessary for improving the focus, of which due to the tremendous amount of divergence and/or diffusion created by transmitting through them clouds makes the need as for anything in excess of a km worth of parabolic source somewhat unnecessary, though perhaps offering a bit more photon delivery efficiency, which certainly could be a factor if there were a shortage of energy by which to drive such an illumination. Although, upon Venus there's hardly anything but a shortage of energy.
Because the bulk of the atmospheric suspended acid is in fact in a transparent droplet form (more spherical droplets than not, and of at least 25% H2O if not 33% H2O) rather than crystal, as such the opacity of such a cloud barrier would not likely fall below 10%, in fact it would be just as likely that a window of 25% opacity for the 400~450 nm spectrum would exist, thus as much as 25% worth of those original photons will manage to illuminate through the clouds to a point where others as snookered and arrogant as far too many Earth humans might notice.
Ongoing observations of such illuminations within the Venus seasons of daytime, as well as for those noticed of their Venus season of nighttime is in fact offering the utmost unusual of all observed topics among all other observed planets, at least as far as this facet being most likely artificial than not. That combined along with the rather obvious notations I've made on behalf of other life for more than three years, of there being significant numbers of massive structures, including a few complex reservoirs, a modified surface feature looking very much as a sizable tarmac, but then there's also a rather substantial rigid airship parked partially into it's hanger or storage bay, with a couple of rows of spherical storage tanks recessed into the landscape (gees folks, I wounder how the hell mother nature managed to accomplish all of that?) along with creating a rational township like community, having of all things a somewhat central parabolic item of good diameter, and of that parabolic item having a central spire or tower is sort of another dead giveaway. Perhaps the fact that there's clearly a nearby suspension bridge that's spanning a rather substantial canyon/rille, along with all sorts of other highly unusual and thereby interesting items of a more likely artificial nature than not, all of this is apparently asking of our crack NASA moderated observers that have been opposing essentially everything under the sun, and to be telling us we need to ignore absolutely all there is, including ignoring and/or skewing the laws of physics, and not to even mention our having to avoid laws of common sense.
Good grief folks; if there's another planet under our observation that offers even 1% as much to work with, perhaps we should be doing something about it. As not even from all that we've obtained from Mars is worth 1% of what's been discovered about Venus, and that a fact.
If you can provide other numbers for those "ashen lights" as illumination spots, such as their worth of lumens, watts/m2 or photons/m2, and of the peak spectrum involved, and/or anything further upon the topic of "earthshine", or of what any good sort of xenon/mercury illumination cannon or laser might otherwise deliver towards Venus, I'd certainly be interested in including that sort of data, or at least including a link into your research.
There's also a perfectly good side topic of interplanetary quantum packets, a worth of photons being frequency modulated as well as amplitude modulation that'll be sure to knock your shocks off.
