+1 vote
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Dear helpdesk,

I would like to access/download calibrated single exposure images (yes full focal planes).

I just tried to dig a little bit through the websites. I am getting dead ends so far unfortunately.

The DES page

https://des.ncsa.illinois.edu/releases/dr2/dr2-products

clearly mentiones the SEFs (92,263 exposures) but then says they can be accessed through datalab (NOIRLab Astro Data Lab.)

https://datalab.noirlab.edu/des/

but here it seems that only coadds can be accessed?

Can you advise me on how to proceed?

AND if there is PSFEx models for those images, I'd be very interested in obtaining those as well, I am not sure though if they exist and/or got released.

Max

by | 210 views

1 Answer

0 votes

The DES DR2 single-epoch images have their own SIA service called 'des_dr2_se'.  For example, to query the service you might do something like:

from astropy import units as u
from astropy.coordinates import Angle
from pyvo.dal import sia


DEF_ACCESS_URL = "https://datalab.noirlab.edu/sia/des_dr2_se" # DES DR2 Single-epoch SIA service URL
svc = sia.SIAService(DEF_ACCESS_URL)
ra, dec = 73.4708333, -50.3763611

# 4amin search, g-band images
imgTable = svc.search((ra,dec), (Angle(4 * u.arcmin), Angle(4 * u.arcmin)),verbosity=0).to_table()
onlyImage = imgTable[(imgTable['prodtype']=='image') & \
                     ((imgTable['obs_bandpass'] == 'g DECam SDSS c0001 4720.0 1520.0'))].to_pandas()
print(onlyImage['access_url'][1])

I dont believe we have the PSFEx models, certainly not for the SE images.

The DES DR2 coadds can be accessed using the SIA service at:  https://datalab.noirlab.edu/sia/des_dr2

Both the DR2 coadds and SE image files are also available from our file service which can be accessed using the command-line client or the Python API.  For example,

from dl import storeClient as sc
print(sc.ls('des_dr2://dr2_se'))

will list the contents of the DR2 SE directory.  See the HowTo notebook on using the file service in the 'notebooks-latest' folder on the Jupyter notebook server.

Hope this helps, please let us know if you still have questions.

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