=== LEDAS ===

http://www.ledas.ac.uk/arnie5/arnie5.php


=== XMM ===

http://xmmssc-www.star.le.ac.uk/Catalogue/xcat_public_3XMM-DR4.html
http://xmmssc.irap.omp.eu/Catalogue/3XMM-DR8/3XMM_DR8.html


=== Chandra ===

http://cxc.cfa.harvard.edu/csc/cli/


VizieR: http://vizier.u-strasbg.fr/vizier/

=== SDSS DR14 Skyserver  ===

http://skyserver.sdss.org/dr14/en/tools/search/form/searchform.aspx


Examples:

---

curl -o cx_out.xml --form coordFormat=decimal --form outputFormat=vot --form query='SELECT TOP 50 m.name, m.ra, m.dec, m.significance, m.flux_aper_b, m.alpha FROM master_source m WHERE (m.significance > 10.0 AND m.pileup_flag = 0)' 'http://cda.cfa.harvard.edu/csccli/getProperties'

curl -o cx_out.txt --form coordFormat=decimal --form query=@csc_query.sql 'http://cda.cfa.harvard.edu/csccli/getProperties'


Data/csc_query.sql:

SELECT DISTINCT m.name, m.ra, m.dec, m.extent_flag, m.err_ellipse_r0, m.err_ellipse_r1, m.conf_flag, m.flux_aper_b, m.flux_aper_w, m.significance FROM master_source m WHERE (m.significance > 10.0 AND m.pileup_flag = 0)


You can substitute the previous query for example with this:
SELECT DISTINCT TOP 1000 m.name, m.ra, m.dec, m.err_ellipse_r0, m.conf_flag, m.sat_src_flag, m.significance, m.flux_aper_b, m.flux_aper_w FROM master_source m WHERE (m.significance > 10.0 AND m.pileup_flag = 0) ORDER BY name ASC


---

=== VOTable ===

http://www.ivoa.net/documents/VOTable/20130315/PR-VOTable-1.3-20130315.html#ToC7