ZTF Metadata

Quick Links

The tables describing the metadata for ZTF products are:

The ZTF data products themselves are available here, for browsing or for retrieving with an API:

How to locate a ZTF file from its metadata

The path of a ZTF data products file can be deduced from its metadata according to the following rules, where the + signs indicate concatenation and the bolded strings represent metadata columns or strings derived from metadata columns.

Below, year is the first four characters of filefracday, month is characters 5--6 of filefracday, day is characters 7--8 of filefracday, and fracday is characters 9--14 of filefracday.

Science Exposures

File Path Pattern:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/sci/'+year/'+month+day+'/'+fracday+'/ztf_'+filefracday+'_'+paddedfield+'_'+filtercode+'_c'+paddedccdid+'_'+imgtypecode+'_q'+qid+'_sciimg_ra'+in_ra+'_dec'+in_dec+'.fits'

where paddedfield is the field padded with initial zeros to 6 characters, paddedccdid is the ccdid padded with an initial zero, suffix = log.txt, mskimg.fits, siimg.fits, sciimlog.txt, sexcat.fits, or log.txt.

Example:

curl --user myemail.astronomy.edu:mypassword -o out.tbl
"https://irsa.ipac.caltech.edu/ibe/search/ztf/products/sci?POS=358.3,25.6"

Based on the metadata, for the first entry we have:

  • filefracday = '20171023296551'
  • year = '2017'
  • month = '10'
  • day = '23'
  • fracday = '296551'
  • paddedfield = '000600'
  • filtercode = 'zr'
  • paddedccdid = '08'
  • imgtypecode ='o'
  • qid = '1'

Therefore, the URL is to the science exposure is:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/sci/2017/1023/296551/ztf_20171023296551_000600_zr_c08_o_q1_sciimg.fits

Calibration Bias

File Path Pattern:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/cal/'+year/'+month+day+'/bias/'+filtercode+'ccd'+paddedccdid+'/q'+qid+'/ztf_'+filestartdate+'_'+filtercode+'_c'+paddedccdid+'_q'+qid+'_bias.fits'

Example:

After logging in, try the following search in your browser:

https://irsa.ipac.caltech.edu/ibe/search/ztf/products/cal?WHERE=ccdid=6+AND+caltype=%27bias%27&CT=html

The first entry has metadata that correspond to:

  • year = '2017'
  • month = '10'
  • day = '14'
  • paddedccdid = '06'
  • qid = '2'
  • filestartdate = '20171014'
  • filtercode = '00'

Therefore, the URL to the bias frame is:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/cal/2017/1014/bias/00/ccd06/q2/ztf_20171014_00_c06_q2_bias.fits

Calibration High Frequency Flat

File Path Pattern:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/cal/'+year/'+month+day+'/hifreqflat/'+filtercode+'/ccd'+paddedccdid+'/q'+qid+'/ztf_'+filestartdate+'_'+filtercode+'_c'+paddedccdid+'_q'+qid+'_hifreqflat.fits'

Example:

After logging in, try the following search in your browser:

https://irsa.ipac.caltech.edu/ibe/search/ztf/products/cal?WHERE=ccdid=6+AND+caltype=%27hifreqflat%27&CT=html

The first entry has metadata that correspond to:

  • year = '2017'
  • month = '10'
  • day = '14'
  • filtercode = 'zr'
  • paddedccdid = '06'
  • qid = '2'
  • filestartdate = '20171014'

Therefore, the URL to the high frequency flat frame is:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/cal/2017/1014/hifreqflat/zr/ccd06/q2/ztf_20171014_zr_c06_q2_hifreqflat.fits

Raw

File Path Pattern:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/raw/'+year/'+month+day+fracdate+'/ztf_'+filefracday+'_'+paddedfield+filtercode+'_c'+paddedccdid+'_'+imgtypecode+'.fits.fz'

Example:

After logging in, try the following search in your browser:

https://irsa.ipac.caltech.edu/ibe/search/ztf/products/raw?WHERE=ccdid=6+AND+imgtype='object'+AND+nid=287&CT=html

The first entry has metadata that correspond to:

  • year = '2017'
  • month = '10'
  • day = '15'
  • filefracday = '20171015354109'
  • fracdate = '354109'
  • filtercode = 'zr'
  • paddedccdid = '06'
  • paddedfield = '000656'
  • imgtypecode = 'o'

Therefore, the URL to the raw frame is:

https://irsa.ipac.caltech.edu/ibe/data/ztf/products/raw/2017/1015/354109/ztf_20171015354109_000656_zr_c06_o.fits.fz