Johnson JHK versus 2MASS JHK

[mdecleir]

Most of the JHK photometry in the data files are from 2MASS, but some are from other references. Currently, the "get_poss_bands" function in stardata.py only includes the Johnson JHK bands and not the 2MASS bands. The 2MASS bands should be added. On the other hand, the scaling of the SpeX SXD spectra always uses the 2MASS bandpasses. A distinction should be made between the Johnson JHK and 2MASS JHK photometry, because their filters are slightly different.