We are interested in knowing how widely used the ANA file support in sunpy is used in the community. This code is legacy C code and is hard to maintain for the sunpy development team, if nobody is making use of it then we are interested in removing it in a future sunpy release.
Please comment here to let us know if you are using it and would like us to continue supporting it.
I even forgot that this was in SunPy, but I think it would be really nice to keep. I understand it is a pain to keep the legacy C code (I also struggle with the same in another package), but I still encounter the format every now and then for files related to the Swedish 1-m Solar Telescope, so I think it would be really good to keep in SunPy for the sake of legacy (e.g. being able to read old data).
As far as I know, this is mostly a couple of C files that are interfaced with a module. If you find the C interface module too hard to maintain, I have a Cython-based version, which may be simpler or just another can of worms.
Old science data (including earlier versions of CRISP but before CHROMIS) are often in ANA format, as well as several calibration files needed. Mostly, the data coming out of the cameras was all in ANA FZ format.
There is almost no public data from the SST. The small archive that exists at the moment has no data in ANA format, but I don’t know if there are plans to expand it to older datasets.