IRSA Moving Object Search Tool (astroquery.ipac.irsa.most)¶
Moving Object Search Tool (MOST) can determine the orbit for a given solar system object then find images that covered the object’s predicted positions in select image datasets housed at IRSA. It can serve as a “precovery” tool to see if newly discovered objects were previously observed.
The URL of the Most interface is:
Input Modes¶
- The service accepts several different input modes:
Solar System Object Name Input (
"name_input")Solar System Object NAIF ID Input (
"naifid_input")MPC One-Line Element Input (
"mpc_input")Orbital Elements Manual Input (
"manual_input")
Name resolution and ephemeris generation for known objects is done via query to JPL’s Horizon database whenever possible. This lookup can fail when name ambiguities exist. For example, entering “Neptune” is unclear because ephemeris for both Neptune and Neptune system barycenter exist.
Most will deliver a messsage if there is an ambiguity. The message may contain suggested NAIF ID’s, e.g. “899:NID” for Neptune.
NAIF ID’s are considered valid input. Satellites and asteroids with the same name may be distinguished by, e.g. “Europa:SAT” and “Europa:AST”.
The ephemeris can also be calculated for comets or asteroids using orbital elements supplied by the user, either individually or in the Minor Planet Center (MPC) one-line format.
Depending on what input mode Most is being queried as, the list of required parameters will change.
Output Modes¶
- The service accepts several different output modes:
Regular- defaultFullBriefVOTableGator
The query_object() method will
return different objects depending on the specified output mode.
Output mode |
Returned object |
|---|---|
|
Dictionary containing |
|
|
|
|
Note
The difference between Regular and Full output mode is non-existant
as the returned data in both cases is identical, as the figures created in
Full mode are not downloaded. The difference between the two modes are
mainly visible in presentation of the data when Most is used via their
online interface. It is, therefore, recommended Regular because the
query will complete significantly faster.
Regular and Full¶
In "Regular" or "Full" output mode query_object()
returns a dictionary containing results, metadata and region keys.
The results key contains a table that maps to the results table returned by
Most service titled Images with a Matched Object Position. The table
contains the following columns:
Column |
Description |
|---|---|
Image_ID |
A unique identifier for the image data, not necessarily the image file name. |
date_obs |
Date (UTC) of the observation. |
time_obs |
Time (UTC) of the midpoint of the observation. |
mjd_obs |
Modified Julian Date (days) of the midpoint of the observation. |
ra_obs |
Ephemeris of the object’s right ascension (deg, J2000). |
dec_obs |
Ephemeris of the object’s declination (deg, J2000). |
sun_dist |
Heliocentric distance of the object (AU). |
geo_dist |
Geocentric distance of the object (AU). |
dist_ctr |
Projected distance from the center of the image (deg). |
phase |
Sun-Object-earth angle (deg). |
vmag |
Estimate of visual magnitude (from Horizons). |
image_url |
Links to download or view the data. |
postcard_url |
Currently |
region_file |
Markers for the moving object in DS9 “region” format. |
The metadata key contains a table which columns change depending on what
catalog (instrument) was queried. Only a small set of columns are guaranteed to
always be present. The following table lays out which columns can be expected
to be present for a given instrument/observatory:
Column |
Description |
|---|---|
General |
|
ra1, dec1, ra2, dec2, etc. |
Right ascension and declination of the 4 corners of the image (deg, J2000) |
match |
match = 1 indicates a matched image (added by Most) |
WISE/NEOWISE |
|
crpix1, crpix2 |
Center of image (pixels) |
crval1, crval2 |
Center of image (deg, J2000) |
equinox |
Equinox of coordinates |
band |
WISE band number; 1 (3.4 microns), 2 (4.6 microns), 3 (12 microns), 4 (22 microns) |
scan_id |
Identification of pole-to-pole orbit scan |
date_obs |
Date and time of mid-point of frame observation UTC |
mjd_obs |
MJD of mid-point of frame observation UTC |
dtanneal |
Elapsed time in seconds since the last anneal |
moon_sep |
Angular distance from the frame center to the Moon (°) |
saa_sep |
Angular distance from the frame center to South Atlantic Anomaly (SAA) boundary (deg) |
qual_frame |
This integer indicates the quality score value for the Single-exposure image frameset, with values of 0 (poor| quality), 5, or 10 (high quality) |
image_set |
image_set=4 for 4band, 3 for 3band, 2 for 2band, and 6, 7 etc. for NEOWISE-R year 1, 2 etc. |
2MASS |
|
ordate |
UT date of reference (start of nightly operations) |
hemisphere |
N or S hemisphere |
scanno |
Nightly scan number |
fname |
FITS file name |
ut_date |
UT date of scan (YYMMDD) |
telname |
Telescope location - Hopkins or CTIO |
mjd |
Modified Julian Date of observation |
ds |
ds=full for 2mass |
PTF |
|
obsdate |
Observation UT date/time YYYY-MM-DD HH:MM:SS.SSS |
obsmjd |
Modified Julian date of observation |
nid |
Night database ID |
expid |
Exposure database ID |
ccdid |
CCD number (0…11) |
rfilename |
Raw-image filename |
pfilename |
Processed-image filename |
ZTF |
|
obsdate |
Observation UT date/time YYYY-MM-DD HH:MM:SS.SSS |
obsjd |
Julian date of observation |
filefracday |
Observation date with fractional day YYYYMMDDdddddd |
field |
ZTF field number |
ccdid |
CCD number (1…16) |
qid |
Detector quadrant (1…4) |
fid |
Filter ID |
filtercode |
Filter name (abbreviated) |
pid |
Science product ID |
nid |
Night ID |
expid |
Exposure ID |
itid |
Image type ID |
imgtypecode |
Single letter image type code |
Spitzer |
|
reqkey |
Spitzer Astronomical Observation Request number |
bcdid |
Post Basic Calibrated Data ID (Lvl. 2 product search) |
reqmode |
Spitzer Astonomical Observation Request type |
wavelength |
Bandpass ID |
minwavelength |
Min wavelength (microns) |
maxwavelength |
Max wavelength (microns) |
time |
UT time of observation |
exposuretime |
Exposure time (sec) |
The key region contains an URL to the DS9 Region file that draws a green
circle over the object, or predicted ephemeride, used in the search.
The results returned in this output mode could contain two additional keys -
fits_tarball and region_tarball - depending on whether the query
parameter with_tarballs (see below) is set to True or False. The
keys will contain a link to an TAR archive of all of the matched FITS and DS9
region files respectively.
Brief and VOTable¶
In these two modes, only the second key (metadata) is returned as either an
Table object, in "Brief" mode, or, in "VOTable"
mode as an VOTableFile object.
The content of these tables is identical to the one described above. The
with_tarballs parameter is also not applicable to these two modes and will
be ignored if provided.
Gator¶
An Table is returned containing the following columns:
Column |
Description |
|---|---|
mjd |
Modified Julian Date of observation |
scan_id |
Scan ID |
frame_num |
Frame number |
ra |
Right Ascension of the object (J2000) |
dec |
Declination of the object (J2000) |
Query Parameters¶
Depending on the selected input_mode the required and optional parameters
differ. Certain parameters are always required and, for some, reasonable
defaults are provided. Parameters that are not applicable to the selected input
mode are ignored.
Parameter |
Required |
Type |
Note |
|---|---|---|---|
catalog |
always required |
str |
Catalog. |
input_mode |
always required |
str |
Input mode. |
output_mode |
always required |
str |
Output mode. |
ephem_step |
always required |
float |
Ephemeris step size, days. |
with_tarballs |
Only in Regular, Full output mode |
bool |
Return tarballs of fits and regions. |
obs_begin |
always optional |
str None |
In |
obs_end |
always optional |
str None |
In |
obj_name |
name_input |
str |
Solar System Object name. |
obj_naifid |
naifid_input |
str |
Object’s NAIF ID. |
obj_type |
mpc_input |
str |
Either |
mpc_data |
mpc_input |
str |
String in MPC’s One-Line format. |
body_designation |
manual_input |
str |
Name of the object described
by the given orbit, does not
need to be a real name. By
default constructed from the
type, i.e |
epoch |
manual_input |
str float |
Epoch of coordinates in MJD. |
eccentricity |
manual_input |
float |
Object’s eccentricity (0-1). |
inclination |
manual_input |
float |
Inclination (0-180 deg). |
arg_perihelion |
manual_input |
float |
Argument of perihelion (0-360 deg). |
ascend_node |
manual_input |
float |
Longitude of the ascending node (0-360 deg). |
semimajor_axis perih_dist |
manual_input |
float |
Semimajor axis for Asteroids and perihelion distance for Comets. In AU. |
mean_anomaly perih_time |
manual_input |
float str |
Mean anomaly for Asteroids
(deg) or perihelion time for
Comets
( |
Examples¶
By default the input mode will be set to "name_input", the times to None
and output mode to Regular. So the only piece of information required is the
object’s name. Since this will search the whole of wise_merged catalog for
any detections of the given asteroid - we will restrict the example query in
time and output in order to have a more manageable output.
So we can query the night of Thursday, 29th of May 2015 for observations of an asteroid Victoria as:
>>> from astroquery.ipac.irsa.most import Most
>>> Most.query_object(output_mode="Brief",
... obj_name="Victoria",
... obs_begin="2014-05-29",
... obs_end="2014-05-30")
<Table length=10>
ra_obj dec_obj sun_dist geo_dist ... moon_sep saa_sep qual_frame image_set
float64 float64 float64 float64 ... float64 float64 int64 int64
---------- --------- -------- -------- ... -------- ------- ---------- ---------
333.539704 -0.779308 1.8179 1.4638 ... 102.339 15.039 10 6
333.539704 -0.779308 1.8179 1.4638 ... 102.339 15.039 10 6
333.589056 -0.747249 1.8179 1.4626 ... 103.825 46.517 10 6
333.589056 -0.747249 1.8179 1.4626 ... 103.825 46.517 10 6
333.638286 -0.71525 1.8179 1.4614 ... 105.327 89.053 10 6
333.638286 -0.71525 1.8179 1.4614 ... 105.327 89.053 10 6
333.687495 -0.683205 1.8178 1.4603 ... 106.803 115.076 10 6
333.687495 -0.683205 1.8178 1.4603 ... 106.803 115.076 10 6
333.736581 -0.65122 1.8178 1.4591 ... 108.294 73.321 10 6
333.736581 -0.65122 1.8178 1.4591 ... 108.294 73.321 10 6
To return more than just a table of image identifiers, use one of the more
verbose output modes - Regular or Full.
>>> matched = Most.query_object(output_mode="Regular",
... with_tarballs=True,
... obj_name="Victoria",
... obs_begin="2014-05-29",
... obs_end="2014-05-30")
>>> type(matched)
<class 'dict'>
>>> matched.keys()
dict_keys(['results', 'metadata', 'region', 'fits_tarball', 'region_tarball'])
>>> matched["metadata"]
<Table length=10>
ra_obj dec_obj sun_dist geo_dist ... moon_sep saa_sep qual_frame image_set
float64 float64 float64 float64 ... float64 float64 int64 int64
---------- --------- -------- -------- ... -------- ------- ---------- ---------
333.539704 -0.779308 1.8179 1.4638 ... 102.339 15.039 10 6
333.539704 -0.779308 1.8179 1.4638 ... 102.339 15.039 10 6
333.589056 -0.747249 1.8179 1.4626 ... 103.825 46.517 10 6
333.589056 -0.747249 1.8179 1.4626 ... 103.825 46.517 10 6
333.638286 -0.71525 1.8179 1.4614 ... 105.327 89.053 10 6
333.638286 -0.71525 1.8179 1.4614 ... 105.327 89.053 10 6
333.687495 -0.683205 1.8178 1.4603 ... 106.803 115.076 10 6
333.687495 -0.683205 1.8178 1.4603 ... 106.803 115.076 10 6
333.736581 -0.65122 1.8178 1.4591 ... 108.294 73.321 10 6
333.736581 -0.65122 1.8178 1.4591 ... 108.294 73.321 10 6
As demonstrated, the returned values are stored in a dictionary and which
metadata key table matches the Brief output mode table.
The fits_tarball and region_tarballs keys store the URL of the TAR
archive containing all 10 images that observed asteroid Victoria on that night.
Individual images that were put into the archive are stored under the results
key:
>>> matched["fits_tarball"]
'https://irsa.ipac.caltech.edu/workspace/TMP_X69utS_13312/Most/pid15792/fitsimage_A850RA.tar.gz'
>>> matched["region_tarball"]
'https://irsa.ipac.caltech.edu/workspace/TMP_X69utS_13312/Most/pid15792/ds9region_A850RA.tar'
>>> matched["results"].columns
<TableColumns names=('Image_ID','date_obs','time_obs','mjd_obs','ra_obj','dec_obj','sun_dist','geo_dist','dist_ctr','phase','vmag','image_url','postcard_url','region_file')>
>>> matched["results"]["time_obs", "image_url"]
<Table length=10>
time_obs image_url
str12 str103
------------ -------------------------------------------------------------------------------------------------------
11:00:08.319 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/3b/49273b/134/49273b134-w2-int-1b.fits
11:00:08.319 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/3b/49273b/134/49273b134-w1-int-1b.fits
14:09:44.351 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/7b/49277b/135/49277b135-w1-int-1b.fits
14:09:44.351 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/7b/49277b/135/49277b135-w2-int-1b.fits
17:19:09.391 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/1b/49281b/134/49281b134-w2-int-1b.fits
17:19:09.391 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/1b/49281b/134/49281b134-w1-int-1b.fits
20:28:45.431 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/5b/49285b/135/49285b135-w2-int-1b.fits
20:28:45.431 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/5b/49285b/135/49285b135-w1-int-1b.fits
23:38:10.476 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/9b/49289b/134/49289b134-w1-int-1b.fits
23:38:10.476 https://irsa.ipac.caltech.edu/ibe/data/wise/merge/merge_p1bm_frm/9b/49289b/134/49289b134-w2-int-1b.fits
Note
The returned TAR Archives point to the Most service hosted directory which will dissapear after a while, making the URLs return a 404 Not Found Error. The URLs returned by the results table, however, point to the NASA/IPAC Infrared Science Archive, which means that the URLs to the images themselves will remain valid even after the Most URLs expire.