How do you get access to the DES tiles that are tabulated in the des_dr1.tile_info database?

Question

I run a query (using the datalab python module) on the des_dr1.tile_info database.  I get back something that gives me (among other things) filenames for the tiles.  One of these, for example, is:

http://desar2.cosmology.illinois.edu/DESFiles/desarchive/OPS/multiepoch/Y3A1/r2590/DES0033-4206/p01/coadd/DES0033-4206_r2590p01_g.fits.fz

However, when I try to access that URL, it seems that it's not publicly available.

Where can one find the actual DES tiles that are indexed in the tile_info database?

Answer 1

Hi Rob, thanks for reaching out.

Indeed, the tile_info table as ingested from the DES collaboration, refers to URLs at NCSA. But you can access the files at CSDC/Data Lab either by doing cone searches on our SIA service, or by querying directly the IVOA tables.

In your case, if you know the file name already, you could for instance do (e.g. in a Data Lab Jupyter notebook):

# imports
from dl import queryClient as qc, storeClient as sc
import pandas as pd
pd.set_option('display.max_colwidth', None)

# find URL
filename = 'DES0033-4206_r2590p01_g.fits.fz'
sql = "select access_url from ivoa_des_dr1.siav1 where fileref = '%s'" % filename
result = qc.query(sql,fmt='pandas')
print(result)

access_url
0  https://datalab.noao.edu/svc/cutout?col=des_dr1&siaRef=DES0033-4206_r2590p01_g.fits.fz&extn=3
1  https://datalab.noao.edu/svc/cutout?col=des_dr1&siaRef=DES0033-4206_r2590p01_g.fits.fz&extn=2
2  https://datalab.noao.edu/svc/cutout?col=des_dr1&siaRef=DES0033-4206_r2590p01_g.fits.fz&extn=1

# get the URL you want and download the file to your VOSpace at Data Lab
url = result['access_url'][0]
sc.load('%s' % filename, url)

'OK'

After a while (depending on the file size) you will see the downloaded file in your vospace/ directory. I you need it locally, you can download it from there for instance through your browser, or with the 'datalab' command line client, etc. (Let us know if you need pointers for that).

Best regards,
Robert