Currently, HtmIndexer.indexPoints takes a list of RA and Dec as degrees, but it should accept Angle (in addition?):

https://github.com/lsst/meas_algorithms/blob/b830ed4ea3e7b8f529c5a2c6a16249b22b2ad1e4/python/lsst/meas/algorithms/htmIndexer.py#L68

Though because these lists (or numpy arrays) are what esutil.htm expects, there will probably have to be a translation layer here (but that's better than upstream code that calls indexPoints.