mpetroff

While not completely identical, it looks very similar (I also only have strong protanomaly, not complete protanopia, so I wouldn't expect it to look identical).

Color-vision deficiency simulations collapse colors along the confusion lines, but this can be done multiple ways. These different mapping will all look the same (and identical to the original) to a dichromat but will appear different, with different perceptual differences between colors, to a color-normal individual. Simulating in a way that accurately portrays perceived color distances is still an open research problem.

Please don't use rainbow-type palettes, as they generally have poor accessibility for colorblind individuals. With my red deficiency, the middle two colors in this palette look virtually identical.

> Always fun to bump into Polies here :)

Definitely! I wasn't expecting to see a mention of BICEP while reading HN from Pole, particularly not on something as arcane as its star camera.

With images taken at night, you can run the images through Astrometry.net, which is a blind astrometric solver and will provide you with RA / Dec for most images, as long as you have at least a dozen or two stars visible. The code compares asterisms formed by multiple stars to index files built from Gaia or other similar data. This is the technique that's used more frequently for microwave telescopes located where there's a normal diurnal cycle, e.g., CLASS. The smaller the field of the view, the higher the precision, but it also works fine with a camera with a zoom lens.

BICEP, however, is located at the South Pole on a moving ice sheet, requiring frequent updates to its pointing model, and has six months of continuous daylight, so daytime star pointing observations are required. This requires a different technique. Instead of looking at asterisms with multiple stars, the optical pointing telescope is pointed at a single star using an initial pointing model, the telescope pointing is adjusted until the star is centered, and the offset is recorded. This measurement process is repeated for the few dozen brightest stars, which acquires the data needed for refining the pointing model.

BICEP3 actually uses a >20 year old CCD camera with analog video output (BICEP Array uses newer cameras, with more modern sensors). Daytime star pointings are possible by using a low-pass filter to block visible light and take advantage of the sensitivity of CCD / CMOS sensors to the near infrared, where the daytime sky is more transparent, combined with baffling.

> the default color palette is colorblind-friendly

No, it very much isn't. The second and third colors, the orange and the green, look extremely similar to protanopes (red deficiency). Fortunately, there's a plan to fix this for Matplotlib 4.0.

I implemented it as part of a GSoC project a decade ago, which was first included in the 0.91 release in 2015.

You're correct, and the other responses saying otherwise are misinformed. Protanopes do not have long-wavelength cones and thus have reduced sensitivity to that end of the visible spectrum, i.e., red light appears dimmer to such individuals. This is also why red on black (or vice versa) is a color combination with poor accessibility, since it has reduced contrast for protanopes as the red appears darker and thus closer to black.

That's to be expected since the Coblis methods, particularly the v1/ColorMatrix version, are known to be very inaccurate. Unfortunately, it's usually the top search result for "colorblindness simulator," which leads folks with normal color vision who try to check for color vision deficiency accessibility to conclude that the images they're checking are accessible in cases when they're not.