Gemini Queries (astroquery.gemini)¶
Getting Started¶
This module can be used to query the Gemini Archive. Below are examples of querying the data with various parameters.
Positional Queries¶
Positional queries can be based on a sky position. Radius is an optional parameter and the default is 0.3 degrees.
>>> from astroquery.gemini import Observations
>>> from astropy import coordinates, units
>>> coord = coordinates.SkyCoord(210.80242917, 54.34875, unit="deg")
>>> data = Observations.query_region(coordinates=coord, radius=0.3*units.deg)
>>> print(data[0:5])
exposure_time detector_roi_setting ... release dec
------------- -------------------- ... ---------- ---------------
119.9986 Full Frame ... 2008-08-21 54.34877772501
119.9983 Full Frame ... 2008-09-25 54.376194395654
119.9986 Full Frame ... 2008-09-25 54.366916626746
119.9983 Full Frame ... 2008-09-25 54.274527402457
99.9983 Full Frame ... 2013-08-16 54.307561057825
Observation Name Queries¶
You may also do a query by the name of the object you are interested in.
>>> from astroquery.gemini import Observations
>>> data = Observations.query_object(objectname='m101')
>>> print(data[0:5])
exposure_time detector_roi_setting ... release dec
------------- -------------------- ... ---------- ---------------
-- Undefined ... 2013-12-21 --
-- Undefined ... 2013-12-21 --
49.9987 Full Frame ... 2013-08-28 54.348777039949
49.9987 Full Frame ... 2013-08-28 54.346975563951
49.9989 Full Frame ... 2013-08-28 54.347048438693
Observation Criteria Queries¶
Additional search terms are available as optional arguments to the query_criteria
call. These all have default values of None, in which case they will not be considered during the search. The one
exception is radius, which will be set to 0.3 degrees by default if either coordinates or objectname are
specified.
Some examples of available search fields are the instrument used, such as GMOS-N, the observation_type, such as BIAS,
and the program ID. For a complete list of available search fields, see
query_criteria
>>> from astroquery.gemini import Observations
>>> data = Observations.query_criteria(instrument='GMOS-N',
... program_id='GN-CAL20191122',
... observation_type='BIAS')
>>> print(data[0:5])
exposure_time detector_roi_setting detector_welldepth_setting ... release dec
------------- -------------------- -------------------------- ... ---------- ---
0.0 Central Stamp -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
In addition, the criteria query can accept additional parameters via the *rawqueryargs and **rawquerykwargs
optional parameters.
The orderby parameter can be used to pass the desired sort order.
>>> from astroquery.gemini import Observations
>>> data = Observations.query_criteria('centralspectrum',
... instrument='GMOS-N',
... program_id='GN-CAL20191122',
... observation_type='BIAS',
... filter='r',
... orderby='data_label_desc')
Observation Raw Queries¶
Finally, for ultimate flexibility, a method is provided for driving the “raw” query that is sent to the webserver. For this option, no validation is done on the inputs. That also means this method may allow for values or even new fields that were not present at the time this module was last updated.
Regular args search terms are sent down as part of the URL path. Any kwargs are then sent down with
key=value also in the URL path. You can infer what to pass the function by inspecting the URL after a search in the
Gemini website. This call also supports the orderby kwarg for requesting the sort order.
This example is equivalent to doing a web search with this example search .
Note that NotFail, notengineering, RAW, and cols are all sent automatically. Only the additional terms need be passed into the method. If QA or engineering search terms are passed, those will replace the NotFail or notengineering terms respectively.
>>> from astroquery.gemini import Observations
>>> data = Observations.query_raw('GMOS-N', 'BIAS', progid='GN-CAL20191122')
>>> print(data[0:5])
exposure_time detector_roi_setting detector_welldepth_setting ... release dec
------------- -------------------- -------------------------- ... ---------- ---
0.0 Central Stamp -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
0.0 Full Frame -- ... 2019-11-22 --
Authenticated Sessions¶
The Gemini module allows for authenticated sessions using your GOA account. This is the same account you login
with on the GOA homepage at https://archive.gemini.edu/. The astroquery.gemini.ObservationsClass.login
method returns True if successful.
>>> from astroquery.gemini import Observations
>>> Observations.login(username, password)
>>> # do something with your elevated access
File Downloading¶
As a convenience, you can request file downloads directly from the Gemini module. This constructs the appropriate URL and fetches the file. It will use any authenticated session you may have, so it will retrieve any proprietary data you may be permissioned for.
>>> from astroquery.gemini import Observations
>>> Observations.get_file("GS2020AQ319-10.fits", download_dir="/tmp")
Reference/API¶
astroquery.gemini Package¶
Classes¶
|
Query class for observations in the Gemini archive. |