stdpipe.resolve module

stdpipe.resolve.simbadResolve(name='m31')

stdpipe.resolve.parseSexadecimal(string)

stdpipe.resolve.tnsResolve(name='AT2023lxx')

stdpipe.resolve.resolve(string='M33', verbose=False)

Resolve the object name (or coordinates string) into proper coordinates on the sky.

This function attempts multiple resolution methods in order: 1. Decimal degrees (RA Dec in degrees) 2. Sexagesimal coordinates (hours/degrees with minutes and seconds) 3. Simbad name resolution (astronomical objects) 4. TNS name resolution (transients) 5. Astropy SkyCoord.from_name() (fallback)

Parameters:

stringstr, optional

Input string to resolve (object name or coordinates).

verbosebool or callable, optional

Enable verbose output. Can be True/False or a print-like function.

Returns:

astropy.coordinates.SkyCoord or None

Resolved sky coordinates, or None if resolution fails.

Supported Coordinate Formats:

1. Decimal degrees (RA and Dec in degrees, space or comma separated):

   • "123.456 45.678" → RA=123.456°, Dec=+45.678°

   • "123.456, 45.678" → RA=123.456°, Dec=+45.678° (comma-separated)

   • "123.456 -45.678" → RA=123.456°, Dec=-45.678°

   • "10.68, 41.27" → RA=10.68°, Dec=+41.27° (M31)

2. Sexagesimal coordinates (space-separated or colon-separated):

   • Space format: "HH MM SS.ss ±DD MM SS.ss"

   • Colon format: "HH:MM:SS.ss ±DD:MM:SS.ss"

   • Comma can separate RA from Dec: "HH MM SS.ss, ±DD MM SS.ss"

   Examples: - "12 34 56.7 +45 12 34.5" → RA=12h 34m 56.7s, Dec=+45° 12’ 34.5” - "12 34 56.7, +45 12 34.5" → Same (comma between RA and Dec) - "12:34:56.7 +45:12:34.5" → RA=12h 34m 56.7s, Dec=+45° 12’ 34.5” - "12:34:56.7, +45:12:34.5" → Same (comma between RA and Dec) - "12 34 56 45 12 34" → Dec assumed positive if no sign - "00 42 44.3, +41 16 09" → M31 coordinates (comma-separated)

   Note: RA is interpreted as hours (multiplied by 15 to convert to degrees), Dec is interpreted as degrees. This is the standard astronomical convention.

3. Object names (resolved via Simbad, TNS, or Astropy):

   • Messier objects: "M31", "M 31", "m31"

   • NGC/IC objects: "NGC1234", "IC 5146"

   • Named stars: "Betelgeuse", "Vega"

   • Transients: "AT2023lxx", "AT 2023lxx", "SN2023ixf"

   • Coordinates as names: "12h34m56s +45d12m34s" (via Astropy)

Resolution Priority:

The function tries methods in order and returns the first successful match:

1. Decimal degrees parsing (fastest, no network)

2. Sexagesimal parsing (fast, no network)

3. Simbad query (network required)

4. TNS query via Fink API (network required, for transients)

5. Astropy SkyCoord.from_name() (network required, CDS Sesame)

Examples:

>>> from stdpipe.resolve import resolve
    ..

>>>
    ..

>>> # Decimal degrees
    ..

>>> target = resolve("10.68 41.27")
    ..

>>> print(target.ra.deg, target.dec.deg)
    ..

10.68 41.27

>>>
    ..

>>> # Decimal degrees (comma-separated)
    ..

>>> target = resolve("10.68, 41.27")
    ..

>>> print(target.ra.deg, target.dec.deg)
    ..

10.68 41.27

>>>
    ..

>>> # Sexagesimal (space-separated)
    ..

>>> target = resolve("12 34 56 +45 12 34")
    ..

>>> print(f"{target.ra.deg:.2f} {target.dec.deg:.2f}")
    ..

188.73 45.21

>>>
    ..

>>> # Sexagesimal (comma between RA and Dec)
    ..

>>> target = resolve("12 34 56, +45 12 34")
    ..

>>> print(f"{target.ra.deg:.2f} {target.dec.deg:.2f}")
    ..

188.73 45.21

>>>
    ..

>>> # Sexagesimal (colon-separated)
    ..

>>> target = resolve("00:42:44.3 +41:16:09")
    ..

>>> print(f"{target.ra.deg:.2f} {target.dec.deg:.2f}")
    ..

10.68 41.27

>>>
    ..

>>> # Sexagesimal (colon-separated with comma)
    ..

>>> target = resolve("00:42:44.3, +41:16:09")
    ..

>>> print(f"{target.ra.deg:.2f} {target.dec.deg:.2f}")
    ..

10.68 41.27

>>>
    ..

>>> # Object name (requires network)
    ..

>>> target = resolve("M31", verbose=True)
    ..

Resolved by Simbad as M 31

RA = 10.6847 deg, Dec = 41.2688 deg

>>>
    ..

>>> # Transient name (requires network)
    ..

>>> target = resolve("AT2023lxx", verbose=True)
    ..

Resolved by TNS as AT 2023lxx

RA = 123.4560 deg, Dec = -45.6780 deg

>>>
    ..

>>> # Failed resolution returns None
    ..

>>> target = resolve("InvalidObject123")
    ..

>>> print(target)
    ..

None

Verbose Mode:

When verbose=True, prints resolution method and result:

>>> target = resolve("123.456 45.678", verbose=True)
    ..

Resolved as two values in degrees

RA = 123.4560 deg, Dec = 45.6780 deg

You can also provide a custom logging function:

>>> def my_log(*args):
    ..

… print(“[RESOLVER]”, *args)

>>> target = resolve("M31", verbose=my_log)
    ..

[RESOLVER] Resolved by Simbad as M 31

[RESOLVER] RA = 10.6847 deg, Dec = 41.2688 deg

Network Requirements:

• Decimal/sexagesimal parsing: No network required

• Simbad resolution: Queries http://cdsweb.u-strasbg.fr

• TNS resolution: Queries https://api.ztf.fink-portal.org

• Astropy fallback: Queries CDS Sesame service

If network is unavailable, only coordinate parsing will work. Object name

resolution will fail silently and return None.