Wildcard Handling with Astroquery.mast

Wildcard Handling with Astroquery.mast#

Learning Goals#

By the end of this tutorial, you will:

Use the wildcards available for astroquery.mast.Observations criteria queries
Broaden and refine astroquery.mast.Observations criteria queries
Fully utilize the instrument_name criteria, especially for JWST queries
Query for moving targets using target ephemeris and time criteria such as t_min and t_max

Introduction#

This Notebook demonstrates the use of wildcards in astroquery.mast.Observations criteria queries. The use of wildcards is encouraged for certain criteria types (namely, string object types) to ensure your query returns all results.

We will demonstrate 3 use-cases for wildcards when doing criteria queries and emphasize certain criteria where wildcard usage is highly encouraged, particularly for JWST queries. We will also use the last example to demonstrate the use of value ranges when working with float object criteria types.

The workflow for this notebook consists of:

Wildcard overview with astroquery.mast.Observations
1. Wildcard Search with instrument_name
2. Wildcard Search with instrument_name and proposal_id
3. Wildcard Search a Time-sensitive Object with target_name and t_min
Resources

Imports#

import astropy.units as u
import matplotlib.pyplot as plt

from astropy.coordinates import SkyCoord
from astropy.table import Table, unique, vstack
from astropy.time import Time
from astroquery.mast import Observations

Wildcards with `astroquery.mast.Observations`#

The use of wildcards when making astroquery.mast.Observations queries can help ensure you retrieve all observations without leaving anything out. The available wildcards are % and *: % replaces a single character, while * replaces more than one character preceding, following, or in between the existing characters, depending on its placement. See the Observation Criteria Queries section in the astroquery.mast documentation for more information on the wildcards.

Wildcards are only available for certain criteria. string type objects accept wildcards, but float, integer, or any other objects do not accept wildcards.

Users may call the get_metadata method to see the list of query criteria and their data types. The criteria listed as string objects under the Data Type column are criteria that can be called with wildcards:

Observations.get_metadata("observations")

Table length=34

Column Name	Column Label	Data Type	Units	Description	Examples/Valid Values
str21	str25	str7	str10	str72	str116
intentType	Observation Type	string		Whether observation is for science or calibration.	Valid values: science, calibration
obs_collection	Mission	string		Collection	E.g. SWIFT, PS1, HST, IUE
provenance_name	Provenance Name	string		Provenance name, or source of data	E.g. TASOC, CALSTIS, PS1
instrument_name	Instrument	string		Instrument Name	E.g. WFPC2/WFC, UVOT, STIS/CCD
project	Project	string		Processing project	E.g. HST, HLA, EUVE, hlsp_legus
filters	Filters	string		Instrument filters	F469N, NUV, FUV, LOW DISP, MIRROR
wavelength_region	Waveband	string		Energy Band	EUV, XRAY, OPTICAL
target_name	Target Name	string		Target Name	Ex. COMET-67P-CHURYUMOV-GER-UPDATE
target_classification	Target Classification	string		Type of target	Ex. COMET;COMET BEING ORBITED BY THE ROSETTA SPACECRAFT;SOLAR SYSTEM
obs_id	Observation ID	string		Observation identifier, given by mission	U24Z0101T, N4QF18030
...	...	...	...	...	...
s_region	s_region	string	ICRS Shape	STC/S Footprint	Will be ICRS circle or polygon. E.g. CIRCLE ICRS 17.71740689 -58.40043015 0.625
jpegURL	jpegURL	string		Preview Image URL	https://archive.stsci.edu/hst/previews/N4QF/N4QF18090.jpg
distance	Distance (")	float	arcsec	Angular separation between searched coordinates and center of obsevation
obsid	Product Group ID	integer		Database identifier for obs_id	Long integer, e.g. 2007590987
dataRights	Data Rights	string		Data Rights	valid values: public,exclusive_access,restricted
mtFlag	Moving Target	boolean		Moving Target Flag	If True, observation contains a moving target, if False or absent observation may or may not contain a moving target
srcDen	Number of Catalog Objects	float		Number of cataloged objects found in observation
dataURL	Data URL	string		Data URL
proposal_type	Proposal Type	string		Type of telescope proposal	Eg. 3PI, GO, GO/DD, HLA, GII, AIS
sequence_number	Sequence Number	integer		Sequence number, e.g. Kepler quarter or TESS sector

Case 1: Wildcard Search with `instrument_name`#

For our first example we will search for all NIRISS observations taken by a certain proposal/program PI. Our two query criteria are proposal_pi and instrument_name, which are both string object criteria. As such, both can be wildcarded for ease of use.

In fact, it is sometimes necessary to use wildcards when searching on instrument_name. Both HST and JWST use instrument configurations in this field to allow for more precise advanced searches (e.g. NIRISS/IMAGE and STIS/FUV-MAMA). When performing a “generic” search, you must include a wildcard or these more detailed results will be excluded.

We will demonstrate this by looking at the results for the query below:

observations = Observations.query_criteria(proposal_pi="Espinoza, Nestor",
                                           instrument_name="NIRISS*")
observations

Table masked=True length=94

intentType	obs_collection	provenance_name	instrument_name	project	filters	wavelength_region	target_name	target_classification	sequence_number	obs_id	s_ra	s_dec	proposal_id	proposal_pi	dataproduct_type	calib_level	t_min	t_max	t_exptime	em_min	em_max	obs_title	t_obs_release	proposal_type	dataRights	mtFlag	obsid	objID
str7	str4	str7	str12	str4	str13	str8	str13	str54	int64	str50	float64	float64	str4	str16	str8	int64	float64	float64	float64	float64	float64	str70	float64	str3	str16	bool	str9	str9
science	JWST	CALJWST	NIRISS/IMAGE	JWST	CLEAR;GR700XD	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512001001_03101_00001_nis	261.2178777047604	60.430788532878	1512	Espinoza, Nestor	image	2	59995.971151875	59995.97127905093	5.494	600.0	2800.0	SOSS Wavelength and Trace	59996.02417822	CAL	PUBLIC	False	117933676	317525309
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512002001_02101_00001_nis	261.2178777048343	60.43078853290603	1512	Espinoza, Nestor	image	2	59995.98101357639	59995.98102200231	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.18175925	CAL	PUBLIC	False	117933629	317525330
science	JWST	CALJWST	NIRISS/IMAGE	JWST	CLEAR;GR700XD	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512001001_03102_00001_nis	261.2178777047765	60.43078853288411	1512	Espinoza, Nestor	image	2	59995.97207774306	59995.97462126157	164.82	600.0	2800.0	SOSS Wavelength and Trace	59996.02564814	CAL	PUBLIC	False	117933623	317525334
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512003001_02101_00003_nis	261.2178777049821	60.43078853296207	1512	Espinoza, Nestor	image	2	59996.0006165162	59996.00062494213	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.22311345	CAL	PUBLIC	False	117933684	317525350
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512001001_02101_00001_nis	261.2178777047001	60.43078853285514	1512	Espinoza, Nestor	image	2	59995.96321136574	59995.96321979167	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.16189809	CAL	PUBLIC	False	117933677	317525361
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512002001_02101_00004_nis	261.2178777048824	60.43078853292429	1512	Espinoza, Nestor	image	2	59995.98740097222	59995.98740939815	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.18133101	CAL	PUBLIC	False	117933631	317525364
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512003001_02101_00002_nis	261.2178777049756	60.43078853295963	1512	Espinoza, Nestor	image	2	59995.99976318287	59995.9997716088	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.22358799	CAL	PUBLIC	False	117933685	317525369
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512002001_02101_00003_nis	261.2178777048472	60.43078853291094	1512	Espinoza, Nestor	image	2	59995.98273135417	59995.98273978009	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.18243051	CAL	PUBLIC	False	117933632	317525397
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512001001_02101_00002_nis	261.2178777047065	60.43078853285758	1512	Espinoza, Nestor	image	2	59995.96406469907	59995.964073125	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.1616898	CAL	PUBLIC	False	117933622	317525399
science	JWST	CALJWST	NIRISS/SOSS	JWST	F480M	Infrared	BD+60-1753	Star; A dwarfs	--	jw01512003001_02101_00004_nis	261.2178777050174	60.43078853297545	1512	Espinoza, Nestor	image	2	59996.00529503472	59996.00530346065	0.683	4600.0	5000.0	SOSS Wavelength and Trace	59996.22332179	CAL	PUBLIC	False	117933686	317525416
...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	--	--	jw01541001001_04101_00001-seg001_nis	260.1161736742332	38.24216472053897	1541	Espinoza, Nestor	spectrum	2	59738.29788028935	59738.55248649306	18855.408	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700117	335565636
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	Star; Exoplanet Systems; Exoplanets; F dwarfs; F stars	--	jw01541001001_04101_00001-seg004_nis	260.1161771630844	38.24215651109613	1541	Espinoza, Nestor	spectrum	2	59738.29788028935	59738.55248649306	18855.408	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700141	335565664
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	Star; Exoplanet Systems; Exoplanets; F dwarfs; F stars	--	jw01541001001_02101_00002-seg001_nis	260.1161771627305	38.24215651192892	1541	Espinoza, Nestor	image	2	59738.26208069445	59738.26209122685	0.954	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700160	335565688
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	Star; Exoplanet Systems; Exoplanets; F dwarfs; F stars	--	jw01541001001_02101_00001-seg001_nis	260.1161771627287	38.24215651193334	1541	Espinoza, Nestor	image	2	59738.26121625	59738.26122678241	0.954	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700178	335565712
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	Star; Exoplanet Systems; Exoplanets; F dwarfs; F stars	--	jw01541001001_04101_00001-seg003_nis	260.1161771630844	38.24215651109613	1541	Espinoza, Nestor	spectrum	2	59738.29788028935	59738.55248649306	18855.408	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700237	335565746
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	--	--	jw01541001001_04101_00001-seg002_nis	260.1161736742332	38.24216472053897	1541	Espinoza, Nestor	spectrum	2	59738.29788028935	59738.55248649306	18855.408	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700224	335565788
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	HAT-P-14	Star; Exoplanet Systems; Exoplanets; F dwarfs; F stars	--	jw01541001001_04102_00001-seg001_nis	260.1161771633686	38.24215651042748	1541	Espinoza, Nestor	image	2	59738.55390866898	59738.55835982639	329.64	600.0	2800.0	NIRISS Sensitivity and Stability for Transiting Exoplanet Observations	59774.8541666	COM	PUBLIC	False	85700205	335565819
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	CD-38-2551	Star; G stars	--	jw02113-o005_t001_niriss_clear-gr700xd-substrip256	94.33630544540856	-38.32344481007381	2113	Espinoza, Nestor	spectrum	3	60215.75685262732	60216.25049009259	32810.168	600.0	2800.0	Exploring the morning and evening limbs of a transiting exoplanet	60582.96342588	GO	EXCLUSIVE_ACCESS	False	188165781	340693902
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	CD-38-2551	Star; G stars	--	jw02113005001_04103_00001-seg001_nis	94.33630544130956	-38.32344481509817	2113	Espinoza, Nestor	image	2	60216.2528283912	60216.25759748842	329.64	600.0	2800.0	Exploring the morning and evening limbs of a transiting exoplanet	60582.57626142	GO	EXCLUSIVE_ACCESS	False	178895888	340696498
science	JWST	CALJWST	NIRISS/SOSS	JWST	CLEAR;GR700XD	Infrared	CD-38-2551	Star; G stars	--	jw02113005001_04101_00001-seg001_nis	94.33630544945105	-38.3234448051187	2113	Espinoza, Nestor	spectrum	2	60215.77435597222	60215.77448314815	5.494	600.0	2800.0	Exploring the morning and evening limbs of a transiting exoplanet	60582.58410871	GO	EXCLUSIVE_ACCESS	False	178895938	340696553

Our query returned many NIRISS observations led by the PI Dr. Espinoza. Let’s get all the unique values under the instrument_name column to see what our * wildcard picked up.

set(observations['instrument_name'])

{'NIRISS/IMAGE', 'NIRISS/SOSS'}

Our observations have the advanced labeling; had we simply set instrument_name = "NIRISS", we would have missed several observations. For more details on this advanced labeling, see the JWST Instrument Names page.

A note of caution: There is such a thing as too many wildcards#

You can be too generous with the wildcards, so be sure to exercise caution in their use. Too much ambiguity can lead to unintended results. Let’s take a look at our example below.

observations = Observations.query_criteria(proposal_pi='Espinoza, Nestor',
                                           instrument_name='NIR*') # Surely only one instrument begins with 'NIR'
set(observations['instrument_name'])

{'NIRISS/IMAGE', 'NIRISS/SOSS', 'NIRSPEC/SLIT'}

This query returns NIRSPEC/SLIT observations in addition to the NIRISS ones, which is not what we intended.

Case 2: Wildcard Search with `instrument_name` and `proposal_id`#

Let’s add an additional string criterion and wildcard into the mix. We’ll do this with the proposal_id field which, despite its numeric content, is encoded as a string.

Let’s query for a four digit proposal/program IDs that begin with 15.

observations = Observations.query_criteria(proposal_pi='Espinoza, Nestor',
                                           instrument_name='NIRISS*',
                                           proposal_id=['15%%']) # Only a four digit result will match this

set(observations['proposal_id']), set(observations['instrument_name'])

({'1512', '1541'}, {'NIRISS/IMAGE', 'NIRISS/SOSS'})

Case 3: Create a Moving Target Ephemeris using MAST Observations with Wildcard Search#

We will be querying for image observations of Comet 67P Churyumov-Gerasimenko observed through the Hubble Space Telescope’s Advanced Camera for Surveys (ACS) Wide Field Camera (WFC). This comet’s name can be listed in different ways, so we will use * wildcards in our criteria query.

observations = Observations.query_criteria(target_name="*67P*",
                                           instrument_name="ACS/WFC")

print(f"{len(observations)} total observations" + "\n")
print("Listed target names:")
print(set(observations['target_name']))

140 total observations

Listed target names:
{'COMET-67P-CHURYUMOV-GERASIMENK', 'COMET-67P-CHURYUMOV-GER-UPDATE'}

Above there are two names we get for Comet-67P. You should exercise caution when searching on the target_name criteria, since this is often entered by the PI who proposed the observation and can vary from person to person.

In the remainder of this notebook, we will construct a bare-bones ephemeris using the filtered MAST observations of this object and their metadata. We will then do some reverse engineering to query for the target based on coordinates using the ephemeris table, and hope that we get the same results back! Let’s begin:

For simplicity, let’s work only with the 'COMET-67P-CHURYUMOV-GERASIMENK' observations to create our ephemeris.

mask = observations["target_name"] == "COMET-67P-CHURYUMOV-GERASIMENK"
filtered_observations = observations[mask]
filtered_observations

Table masked=True length=70

intentType	obs_collection	provenance_name	instrument_name	project	filters	wavelength_region	target_name	target_classification	sequence_number	obs_id	s_ra	s_dec	proposal_id	proposal_pi	dataproduct_type	calib_level	t_min	t_max	t_exptime	em_min	em_max	obs_title	t_obs_release	proposal_type	dataRights	mtFlag	obsid	objID
str7	str3	str6	str7	str3	str12	str7	str30	str89	int64	str36	float64	float64	str5	str14	str5	int64	float64	float64	float64	float64	float64	str119	float64	str3	str6	bool	str8	str9
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis06020	290.9147892768	-27.90546497065	13863	Hines, Dean C.	image	3	56979.51550486111	56979.66734533565	6280.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57344.94447902	GO	PUBLIC	True	24839236	302503482
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis01010	281.2558788729	-31.01619293249	13863	Hines, Dean C.	image	3	56887.26573422454	56887.49156755787	7200.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57252.60829852	GO	PUBLIC	True	24839228	301750450
science	HST	CALACS	ACS/WFC	HST	F775W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis04010	290.2735685756	-28.02183037337	13863	Hines, Dean C.	image	3	56977.44858376157	56977.454660219904	300.0	690.0	860.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57342.8724883	GO	PUBLIC	True	24839231	300632430
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis04020	290.2770693515	-28.02111499969	13863	Hines, Dean C.	image	3	56977.45820188658	56977.611049039355	6280.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57342.94112256	GO	PUBLIC	True	24839232	301750132
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis05020	290.5842080034	-27.96554445143	13863	Hines, Dean C.	image	3	56978.454278206016	56978.60601420139	6280.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57343.75185176	GO	PUBLIC	True	24839234	302511196
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis02010	281.1070302812	-31.0066887554	13863	Hines, Dean C.	image	3	56888.26101200232	56888.48685717593	9600.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57253.60605318	GO	PUBLIC	True	24839229	302510983
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET BEING ORBITED BY THE ROSETTA SPACECRAFT	--	jcz302010	149.0210592664	17.79521475611	14261	Hines, Dean C.	image	3	57306.00024725695	57306.02970309028	1868.0	470.0	720.0	Post-Perihelion Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Continued Support of the Rosetta Mission	57672.2263889	GO	PUBLIC	True	25001891	300634637
science	HST	CALACS	ACS/WFC	HST	F775W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis06010	290.9112348543	-27.90621726673	13863	Hines, Dean C.	image	3	56979.505933368055	56979.51200949074	300.0	690.0	860.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57344.94012718	GO	PUBLIC	True	24839235	300631034
science	HST	CALACS	ACS/WFC	HST	F606W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis03010	280.9542165962	-30.99542663878	13863	Hines, Dean C.	image	3	56889.322632372685	56889.548465706015	9600.0	470.0	720.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57254.78804398	GO	PUBLIC	True	24839230	302531385
science	HST	CALACS	ACS/WFC	HST	F775W	Optical	COMET-67P-CHURYUMOV-GERASIMENK	COMET; COMET-67P-CHURYUMOV-GERASIMENKO WHICH IS THE PRIMARY TARGET FOR ROSETTA SPACECRAFT	--	jcis05010	290.5806735758	-27.96626079113	13863	Hines, Dean C.	image	3	56978.44466003472	56978.45073653935	300.0	690.0	860.0	Imaging Polarimetry of the 67P/Churyumov-Gerasimenko with ACS: Supporting the Rosetta Mission	57343.70451382	GO	PUBLIC	True	24839233	300630619
...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...	...
science	HLA	HLA	ACS/WFC	HLA	F606WPOL120V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_03_acs_wfc_f606wpol120v_05	280.9325907501443	-30.994283914594472	13863	Hines	image	2	56889.46823	56889.48214	1200.0	nan	nan	--	57254.78804398	HLA	PUBLIC	--	25981104	67948371
science	HLA	HLA	ACS/WFC	HLA	F606WPOL60V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_02_acs_wfc_f606wpol60v_05	281.1070408364967	-31.006679797131913	13863	Hines	image	2	56888.26101	56888.27492	1200.0	nan	nan	--	57253.60605318	HLA	PUBLIC	--	25981096	67948363
science	HLA	HLA	ACS/WFC	HLA	F606WPOL0V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_14261_01_acs_wfc_f606wpol0v_04	148.66128404740527	17.89261143672076	14261	Hines	image	2	57305.47852	57305.48394	467.0	nan	nan	--	57671.63094901	HLA	PUBLIC	--	26004660	67971927
science	HLA	HLA	ACS/WFC	HLA	F606WPOL60V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_05_acs_wfc_f606wpol60v_07	290.5879921960003	-27.964852625069675	13863	Hines	image	2	56978.46554	56978.47464	785.0	nan	nan	--	57343.75185176	HLA	PUBLIC	--	25981124	67948391
science	HLA	HLA	ACS/WFC	HLA	F775W	OPTICAL	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_04_acs_wfc_f775w_01	290.27357746214466	-28.021822337884565	13863	Hines	image	2	56977.44859	56977.45034	150.0	690000000000.0	860000000000.0	--	57342.8724883	HLA	PUBLIC	--	25981116	67948383
science	HLA	HLA	ACS/WFC	HLA	F606WPOL120V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_06_acs_wfc_f606wpol120v_04	290.958971742416	-27.896776007673772	13863	Hines	image	2	56979.65826	56979.66736	785.0	nan	nan	--	57344.94447902	HLA	PUBLIC	--	25981131	67948398
science	HLA	HLA	ACS/WFC	HLA	F606WPOL60V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_05_acs_wfc_f606wpol60v_08	290.62052219537316	-27.959104624398297	13863	Hines	image	2	56978.57397	56978.58307	785.0	nan	nan	--	57343.75185176	HLA	PUBLIC	--	25981125	67948392
science	HLA	HLA	ACS/WFC	HLA	F606WPOL60V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_02_acs_wfc_f606wpol60v_08	281.0749808366519	-31.004106747569107	13863	Hines	image	2	56888.47296	56888.48688	1200.0	nan	nan	--	57253.60605318	HLA	PUBLIC	--	25981099	67948366
science	HLA	HLA	ACS/WFC	HLA	F606WPOL60V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_14261_02_acs_wfc_f606wpol60v_03	149.02105347495342	17.795211192797524	14261	Hines	image	2	57306.00024	57306.00566	467.0	nan	nan	--	57672.2263889	HLA	PUBLIC	--	26004663	67971930
science	HLA	HLA	ACS/WFC	HLA	F606WPOL0V	--	COMET-67P-CHURYUMOV-GERASIMENK	--	--	hst_13863_04_acs_wfc_f606wpol0v_01	290.28081209582683	-28.020432700528893	13863	Hines	image	2	56977.46947	56977.47856	785.0	nan	nan	--	57342.94112256	HLA	PUBLIC	--	25981108	67948375

Now that we have our filtered observations, let’s sort the rows of this table based on the t_min criteria, which refers to the start time of the exposure in MJD.

filtered_observations.sort("t_min")

Now that we’ve sorted our table, let’s construct a basic ephemeris showing the path of our object over time (with t_min, or exposure start in MJD, as our time component):

ephemeris = Table([filtered_observations["s_ra"],
                   filtered_observations["s_dec"],
                   filtered_observations["t_min"]], names=("ra", "dec", "t_min"))

Let’s display the contents of our ephemeris, and use it to generate a plot of the comet’s path:

ephemeris.sort("t_min")
ephemeris

Table length=70

ra	dec	t_min
float64	float64	float64
281.2558788729	-31.01619293249	56887.26573422454
281.1070408364967	-31.006679797131913	56888.26101
281.1070302812	-31.0066887554	56888.26101200232
281.1045408863173	-31.00650879708346	56888.27707
281.0975108367455	-31.006933797314236	56888.32419
281.0951608865579	-31.006770747268593	56888.34025
281.0868808868347	-31.005851797486205	56888.39054
281.0845408866453	-31.005687797434355	56888.40661
281.0773208868312	-31.004271747618215	56888.4569
281.0749808366519	-31.004106747569107	56888.47296
...	...	...
149.02105347495342	17.795211192797524	57306.00024
149.0210592664	17.79521475611	57306.00024725695
149.02788342509825	17.794214142733026	57306.00826
149.03383347531883	17.791933192580494	57306.01628
149.0387234255141	17.789775192433133	57306.02429
149.38633343179924	17.696582189227897	57306.53082
149.386341824	17.6965860963	57306.530825775466
149.39313343193777	17.695584189165338	57306.53884
149.39905343216378	17.69330118900645	57306.54686
149.40391343235848	17.69114218886538	57306.55487

plt.figure(figsize=(12,8))
plt.scatter(ephemeris[0:18]['ra'], ephemeris[0:18]['dec'], color='royalblue', s=200, lw=1., edgecolor='k')

plt.xlabel("Right Ascension (deg)", fontsize=20)
plt.ylabel("Declination (deg)", fontsize=20)

plt.title("Sky Coordinates", fontsize=20)

plt.xticks(fontsize=15)
plt.yticks(fontsize=15)
plt.grid()

../../../_images/96894c94a5ce102362b229492ddf44abf0a9097d2dd33761b6be7665020ac3d4.png

You can choose to save the ephemeris table in your current working directory by running the cell below:

# Overwriting is not necessary, but prevents this Notebook from failing STScI's automated testing
ephemeris.write('ephemeris-comet67p-cg.csv', format='ascii', overwrite=True)

Resources#

The following is a list of resources that were referenced throughout the tutorial, as well as some additional references that you may find useful:

Citations#

If you use any of astroquery’s tools for published research, please cite the authors. Follow this link for more information about citing astroquery:

Citing astroquery

About This Notebook#

If you have comments or questions on this notebook, please contact us through the Archive Help Desk e-mail at archive@stsci.edu.

Author: Jenny V. Medina
Keywords: astroquery, wildcards, moving target
Last Updated: Jun 2023