Every time somebody uses the word measured and exact in a sentence a kitten dies. Don't be a kitten killer. It may well be 30 degrees but it's not possible to differentiate 29.994 and 30.001 given the methodology. For instance for the other angle, we have 135 (90+35, eyeballed), 140 (measured), 138.5 (also measured), 137.51 (golden angle), 138.32 (argument of periapsis). All of which are plausible within the precision of the image.
There's some interesting points there. If we're supposed to measure the angle then the angle can't be used to describe an object more than a few hundred LY away. At the limits of measurement precision that starts to result in an error more than system separation (10 to 20 LY). In fact it pretty much ensures terrestrial. If we're supposed to derive it (e.g. 137.51 or 138.32) that has sufficient precision to then be used in a calculation to explicitly describe a line or distance accurate to thousands of LY.
Just my little bit of pedantic-ism.