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Diy honeycomb grid - calculation

Started Aug 25, 2017 | Discussions thread
ProfHankD
ProfHankD Veteran Member • Posts: 9,147
Re: Diy honeycomb grid - calculation

JRM PT wrote:

I've e-mailed honeycombgrids.com but they've answered back with a very "inconsistent" formula of TAN(alpha)=D/L <=> alpha=ATAN(D/L) that doesn't make any sense e.g, for 90º the Tangent is infinite...

From analysis of data collected on their website, a better approach would be alpha=ASEN(D/L). I'll make some experiences and post my results as soon as I find some black straws (looks like black is out of fashion this days...)

As I said in my first post here, I believe geometrically it should be approximately 2*atan(strawlength/diameter) for a black straw -- they're missing a factor of 2 because the light spreads equally in all directions, not just one.

Again, that's for one straw lit from behind by a rather perfect light source. If you have an array of straws, then the angles are the same, but your grid is intersecting the light cone with a larger area. The marginal rays within one straw intersect half the strawlength back from the front (so that's the virtual origin of the light), but for an array of straws, the marginal ray intersection will be much farther back.

PS: I still think 3D printing or stacked egg-crate (as I and BobORama discussed above) is a better approach than hard-to-get black straws....

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