Healpix - Converting longitude, latitude to galactic coordinates

Question

I have a Healpix Pixel Coordinated file https://wwwmpa.mpa-garching.mpg.de/~ensslin/research/data/faraday2020.html

This contains the Latitude and Longitude values which I want to implement in a skyplot. The values however need to be converted to Galactic coordinates (l,b) first.

The code I have is:

from astropy.io import fits
from astropy import units as u
from astropy.coordinates import Galactic
import matplotlib.pyplot as plt
import h5py
from astropy_healpix import HEALPix

filename='pixel_coords_map_ring_galactic_res9.fits'

hdulist=fits.open(filename) 
nside = hdulist[1].header['NSIDE']
order = hdulist[1].header['ORDERING']
hp = HEALPix(nside=nside, order=order, frame=Galactic())    

print(hdulist[1].header)

ggl = hdulist[1].data['LONGITUDE']           #storing coordinate values in ggl and ggb
ggb = hdulist[1].data['LATITUDE'] 

gl = ggl * u.degree                            #convering to galactic coordinates
gb = ggb * u.degree

c = Galactic(l=gl,b=gb) 

l_rad = c.l.wrap_at(180 * u.deg).radian
b_rad = c.b.radian

Is there a more efficient way to do the conversion from long-lat to galactic or a Healpix function? Please help.

Answer 1

This code is from an earlier answer I wrote. Doesn't it convert long-lat to u.deg in Galactic coordinates? Ref: Plotting mean and standard dev values on skyplot using astropy
Note: This is the link I used to get the HEALPix file: ('pixel_coords_map_ring_galactic_res9.fits')

from astropy.io import fits                        
from astropy import units as u
from astropy.coordinates import SkyCoord

fits_file = 'pixel_coords_map_ring_galactic_res9.fits'  #healpix

with fits.open(fits_file) as hdulist:
    nside = hdulist[1].header['NSIDE']
    order = hdulist[1].header['ORDERING']
        
    ggl = hdulist[1].data['LONGITUDE']           #storing coordinate values in ggl and ggb
    ggb = hdulist[1].data['LATITUDE'] 
    
    gl = ggl * u.degree                            #convering to galactic coordinates
    gb = ggb * u.degree
    
    c = SkyCoord(l=gl,b=gb, frame='galactic', unit = (u.deg, u.deg))  
    l_rad = c.l.wrap_at(180 * u.deg).radian            #X Axis
    b_rad = c.b.radian
    print(len(l_rad), len(b_rad))