Two minute error in Greenwich Mean Sidereal Time

[ABG]

I came up with another debugging tool for the floating point error case ...

How many bits are needed to store the ratio of total milliseconds from 1970 (1685632697000) divided by those two minutes (118458)?

1685632697000 / 118458 ~ 14,229,791.9

2^10 = 1024, so
16,000,000 ~ 2^4 * 2^10 * 2^10 , so 16,000,000 is roughly 2^24.

A single precision floating point number mantissa is 24 bits.

How does that number of bits compare to the mantissa length of an AI2 floating point number?

Unfortunately, according to

Strings, numbers, what size can they have?

I’ll address the question in three parts as the actual answer is somewhat complicated. In particular, it’s important to know that at the core of App Inventor is an implementation of the Scheme language called Kawa. Theoretical String Length There are two different internal string types in App Inventor. Kawa provides a mutable string type called FString and then there’s Java’s standard String type. Conversions are done from FString to String on an as needed basis to interact with the parts of th…

AI2 floats are 64 bits.

So I can't blame the difference on mantissa length.

That still does not rule out the possibility of order of operations in that formula for preserving precision in intermediate steps.