Crossmatching SDSS catalog with my database catalog returns no values

Question

I am trying to cross-match my catalogue sample with SDSS DR17. Unfortunately, it keeps returning no values. I know there's an overlay between my sample and SDSS because I have crossmatched the same sample with SDSS Dr16 through TOPCAT and Vizier. Below is the python code:

sdss_sql = "SELECT c.* \
        FROM {} AS o, \
        sdss_dr17.photoplate AS c \
        WHERE q3c_join(o.ra, o.dec, c.ra, c.dec, {})".format('mydb://sample', 100/3600)
df = convert(qc.query(sql = sdss_sql, async_ = False))

What do you suggest I do?

Answer 1

Thanks for reaching out. I just tried this experiment:

- Generate a small mydb table with 1000 rows from sdss_dr17.specobj table

- Run the same crossmatch SQL as you have, i.e. against sdss_dr17.photoplate.

And it worked. So, I think it would be good to see your mydb table. Could you maybe post a (sub)sample, for instance as a CSV file, to datalab@noirlab.edu so that we can take a look?

Thanks,
Robert