Isophotes & Pen Plotting

[austin-schick]

Hi Bjorge,

I hope you're having a good week! I'm working on an art project where I'd like to recreate Luminet's first black hole "picture" using a pen plotter / drawing robot. My plan is to use white pen on black paper.

Based on this article by Luminet, it sounds like he created his image by first calculating the isophotes around the black hole, then filling in the space between the isophotes with different densities of dots based on the flux in that space.

The final black and white “photographic” image was obtained from these [isophote] patterns. However, lacking at the time of an appropriate drawing software, I had to create it by hand. Using numerical data from the computer, I drew directly on negative Canson paper with black India ink, placing dots more densely where the simulation showed more light – a rather painstaking process!

This library seems almost perfect for my project, but I don't see a quick way to calculate the isophotes. Is this a feature you'd consider adding, in addition to the existing isoradials and isoredshifts?

Thanks for your consideration,
Austin

[bgmeulem]

Hi Austin!

The isophotes are the last thing I'd need to add to make the library complete. As of today, I haven't found a neat way to do this though.

In the meantime, I can recommend to use the sample_photons method instead. These photons have a flux associated with each sampled coordinate. You could reject the sampling with a probability proportional to their flux to get to the same idea as luminet, and have an image where the amount of photons is proportional to the luminosity.

Cheers
Bjorge

[bgmeulem]

Alternatively, you can simply sample a decent amount of photons and use matplotlibs tricontour for isofluxlines