How to download KPF Solar data from the Keck Observatory Archive

This tutorial was originally developed for the Sun-as-a-Star Splinter at the Extremely Precise Radial Velocities Sixth Workshop (EPRV6) in June 2024.
Main contrutors: Ryan Rubenzhal and Khaled Al Moulla.

This tutorial uses the KOA Python API. Keck also provides official tutorials and more examples for accessing all types of calibration data.
PyKOA requires Python 3.6 or above and astropy. To install the package use:

                
                pip install --upgrade pykoa


Import packages and set up output directory

                import io
import os
import sys
import glob
import numpy as np
import matplotlib as mpl
import matplotlib.pyplot as plt

from pykoa.koa import Koa 
from astropy.io import fits
from astropy.time import Time
from astropy.table import Table, Column

outdir = 'sun_kpf_l2/'
os.makedirs(outdir, exist_ok=True)


More details about KOA can be found with

                help(Koa)


Submit the query by date or datetime range. This will return all KPF files during the time range.
PyKOA supports several output table formats, which are selected with the 'format' field. These formats are: IPAC (column delimited ASCII; default), VOTable, CSV, and TSV. All the examples below deliver output in IPAC format.

                # Query a specific UTC date/time range
Koa.query_datetime(instrument='kpf',
    datetime='2024-06-03 18:30:00/2024-06-03 22:30:00', # UTC
    outpath=f'{outdir}/datetime.kpf.tbl', 
    format='ipac')

# or query the full UTC date
# Koa.query_date(instrument='kpf',
#     date='2024-06-03',
#     outpath=f'{outdir}/datetime.kpf.tbl', 
#     format='ipac')

rec = Table.read (f'{outdir}/datetime.kpf.tbl',format='ipac')


Or we can query by data type (solar).

                param = dict()
param['instrument'] = 'kpf'
param['target'] = 'Sun'
param['date'] ='2024-06-03' # can specify a date as well

# or date range
# param['datetime'] = '2024-06-01 00:00:00/2024-06-30 23:59:59'

Koa.query_criteria(param, 
    f'{outdir}/solar.kpf.tbl',
    format='ipac')

rec = Table.read(f'{outdir}/solar.kpf.tbl', format='ascii.ipac')


Download the data and load the files. All the downloaded data with file types and extensions can be found at this link. This download includes the level 0, 1 and 2 data.

                Koa.download(f'{outdir}/solar.kpf.tbl',  
    format='ipac', 
    outdir=f'{outdir}/data', 
    # calibfile=1, # whether to also look for associated calibration files
    lev1file=1,   # whether to also download L1 spectra
    start_row=152,end_row=153   # can specify range in the table
    )

glob.glob(f'{outdir}/data/lev0/*fits')

# Files
files = glob.glob(f'{outdir}/data/lev0/*fits')
Nfile = len(files)

hdu = fits.open(files[0])


For this tutorial, let us plot the level 0 data

                fig, axes = plt.subplots(2,2, figsize=(8,8), sharex=True, sharey=True, 
                         gridspec_kw={'hspace':0, 'wspace':0})

axes[0,0].imshow(hdu['RED_AMP1'].data  , origin='lower', aspect='auto')
axes[0,1].imshow(hdu['RED_AMP2'].data  , origin='lower', aspect='auto')
axes[1,0].imshow(hdu['GREEN_AMP1'].data, origin='upper', aspect='auto')
axes[1,1].imshow(hdu['GREEN_AMP2'].data, origin='upper', aspect='auto')
HARPS-N Solar Plot