A couple of months ago I was having trouble getting a `\bigtimes` symbol that worked well. A few libraries have one, but they all did all sorts of other troublesome things to how math was formatted. In the end I was suggested to just take the code that `mathabx` uses to make `\bigtimes` and that's worked fantastically:

```
\DeclareFontFamily{U}{mathx}{\hyphenchar\font45}
\DeclareFontShape{U}{mathx}{m}{n}{
  <5> <6> <7> <8> <9> <10>
  <10.95> <12> <14.4> <17.28> <20.74> <24.88>
  mathx10
}{}
\DeclareSymbolFont{mathx}{U}{mathx}{m}{n}
\DeclareMathSymbol{\bigtimes}{1}{mathx}{"91}

```

Now I find myself in deed of a variable sized `$\ast$` and I was wondering how to adapt this code to do it. Clearly I need to write a new `DeclareMathSymbol` line and I presume that I need to input the character code for `ast` into where `"91` is. I wrote something to brute force checking a couple hundred values of integers and see if I could find the symbol that way, but I could not (and it also made me feel mildly silly). I glanced around a little bit and found the `\meaning` command, which did not seem to give the same result. Furthermore I lack a general understanding of latex programming past defining simple macros. But I presume that there is a table somewhere that would have what I'm looking for, so that if in the future I need to make some math symbol variable-sized I don't always have to ask the fine people of tex.stackexchange. 

Edit: For my end solution I ended up switching the base font family to cmsy and just making the sole purpose of the font family be to make large characters, i.e.:

```
\DeclareFontFamily{U}{large}{\hyphenchar\font45}
\DeclareFontShape{U}{large}{m}{n}{
  <27>
  cmsy10
}{}
\DeclareMathSymbol{\bigtimes}{1}{large}{"02}
\DeclareMathSymbol{\bigtest}{1}{large}{"03}

```

Although this isn't quite optimal because it introduces a large number of warnings to my log files.