Observations

Direct access to the unified observations catalog — 12.4M rows of multi-wavelength data spanning both per-frequency SED measurements and time-series lightcurves, distinguished by an is_lightcurve flag.

Catalogs: MMDCGR (Fermi γ-ray), MMDCOUV (Swift UVOT), MMDCXRT (Swift XRT), MMDCXRT_ORBIT (Swift XRT, per orbit), MMDCNuX (NuSTAR), ASAS-SN, ZTF, PanSTARRS-LC, SMARTS.

Filtered Query

# SED rows only, X-ray catalog, latest 100 by mjd_mid
rows = client.observations.query(
    catalog="MMDCXRT",
    is_lightcurve=False,
    limit=100,
)
for r in rows:
    print(f"{r.catalog} obsid={r.obsid} freq={r.frequency:.2e} flux={r.flux:.2e}")

# ZTF R-band lightcurve within an MJD window
lc = client.observations.query(
    catalog="ZTF",
    is_lightcurve=True,
    filter_band="R",
    mjd_min=60000,
    mjd_max=60100,
    ordering="-mjd_mid",
)

Cone Search

HEALPix-indexed spatial search (5 arcsec default, server caps prefilter at 4096 pixels):

# All observations within 10″ of 3C 273
near = client.observations.cone_search(
    ra=187.27791667,
    dec=2.05238889,
    radius_arcsec=10,
)

# Combine cone search with other filters
recent_lc = client.observations.cone_search(
    ra=187.27791667, dec=2.05238889, radius_arcsec=30,
    is_lightcurve=True,
    mjd_min=60000,
)

Available Filters (on both query() and cone_search())

Param	Type	Description
catalog	str	Catalog code (see list above)
filter_band	str	Photometric band (R, V, G, W1, …)
is_lightcurve	bool	True=LC only, False=SED only, omit=both
is_upper_limit	bool	Filter by upper-limit flag
obsid	str	Exact telescope observation ID
mjd_min, mjd_max	float	MJD range bounds
ordering	str	Sort key, - prefix for descending
limit	int	Cap returned rows

Reading Results

Each Observation carries its own is_lightcurve flag so a mixed result can be split client-side:

rows = client.observations.query(catalog="MMDCGR", limit=200)
lc  = [r for r in rows if r.is_lightcurve]
sed = [r for r in rows if not r.is_lightcurve]

SED rows carry frequency/mjd_start/mjd_end, LC rows carry mjd_mid/filter_band. The MMDC* catalogs auto-attach the Sahakyan et al. 2024 reference:

row = client.observations.query(catalog="MMDCXRT", limit=1)[0]
if row.reference:
    print(row.reference.bibcode)  # "2024AJ....168..289S"
    print(row.reference.citation) # "Sahakyan N., et al., 2024, ..."