Comment by sbalula | Hacker News Reader

Comment by sbalula | Hacker News Reader

Congrats on the interesting project! I was curious to know more about the scientific payload: how did you measure the fluorescence? Did you apply excitation light continuously? Or did you rely on ambient light and correct for it when measuring fluorescence? Did you have a control on earth to compensate for any biological related effects? UV and even blue light can stress or even kill cells, or bleach the fluorescence proteins. How do you expect altitude to influence fluorescence? It would be great to look at some data (could not find it on the blog, or github). Acrylic blocks a substancial portion of the UV light!

Edit: Definetely agree with other comment that the whole experience is more important than these details.

Thank you for the kind words! The fluorescence was originally meant to be measured with an AS7273 spectrometer (unfortunately bought a different one, still worked fine though), and measuring ~680 nm. Certainly not a great setup but it worked fine. Light was ambient through acrylic, and I found out far too late that UV blocking effects. Despite that, I feel like the data is still somewhat valid, maybe. I did do some testing with it back on earth, though I can't remember how it correlated.

The data I have is here: https://github.com/radeeyate/StratoSpore/blob/main/software/... - just be warned that the altitude data still isn't the exact same as it was while in the air (GPS not working so I had to take it from someone else).

From https://hps.org/publicinformation/ate/q12178/ :

> UV light, a form of energy, is defined as light having wavelengths between 100 nanometers (nm, 1 billionth of a meter in length) and 400 nm. [...]

> Most acrylic plastics will allow light of wavelength greater than 375 nm to pass through the material, but they will not allow UV-C wavelengths (100–290 nm) to pass through.

In terms of photonic permittivity, Glass is better for cold frames and the like, because acrylic filters out UV light.

Also, Hydrogen peroxide (H2O2) is an algaecide.

/? hydrogen peroxide algaecide https://www.google.com/search?q=hydrogen+peroxide+algaecide

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