.. _astroquery.nist: ******************************** NIST Queries (`astroquery.nist`) ******************************** Tool to query the NIST Atomic Lines database (https://physics.nist.gov/PhysRefData/ASD/lines_form.html). Getting started =============== This is a relatively simple module that you may use to query spectra from NIST. All the results are returned as a `~astropy.table.Table`. To do this you just need to specify the lower and the upper wavelength for the spectrum you want to fetch. These wavelengths must be specified as an appropriate `~astropy.units.Quantity` object, for instance having units of nanometer, or angstrom or the like. For example, to use a lower wavelength value of 4000 Angstroms, you should use ```4000 * u.AA``` and if you want the same in nanometers, just use ```400 * u.nm```. Of course there are several optional parameters you can also specify. For instance use the ``linename`` parameter to specify the spectrum you wish to fetch. By default this is set to "H I", but you can set it to several other values like "Na;Mg", etc. Lets now see a simple example. .. doctest-remote-data:: >>> from astroquery.nist import Nist >>> import astropy.units as u >>> table = Nist.query(4000 * u.AA, 7000 * u.AA, linename="H I") >>> print(table) Observed Ritz Transition Rel. ... Type TP Line ------------- ------------- ------------- ------ ... ---- ----- -------- -- 4102.85985517 24373.2429403 -- ... -- T8637 -- -- 4102.86191087 24373.2307283 -- ... -- T8637 -- -- 4102.8632 24373.223 -- ... -- -- c57 4102.86503481 4102.86503481 24373.2121704 -- ... E2 -- L11759 -- 4102.86579132 24373.2076763 -- ... -- T8637 -- 4102.86785074 4102.86785074 24373.1954423 -- ... M1 -- L11759 -- 4102.8680725 24373.1941249 -- ... -- T8637 -- 4102.892 4102.8991 24373.05 70000 ... -- T8637 L7436c29 -- 4102.8922 24373.051 -- ... -- -- c58 -- 4102.92068748 24372.8815683 -- ... -- T8637 -- ... ... ... ... ... ... ... ... -- 6564.564672 15233.302588 -- ... -- T8637 -- -- 6564.579878 15233.267302 -- ... M1 -- -- -- 6564.583 15233.26 -- ... -- -- c66 6564.584404 6564.584403 15233.256799 -- ... -- T8637 L6891c38 6564.6 6564.632 15233.21 500000 ... -- T8637 L7400c29 -- 6564.608 15233.202 -- ... -- -- c69 6564.66464 6564.66466 15233.07061 -- ... -- T8637 L2752 -- 6564.6662 15233.067 -- ... -- -- c71 -- 6564.667 15233.065 -- ... -- -- c70 -- 6564.680232 15233.034432 -- ... -- T8637 -- -- 6564.722349 15232.9367 -- ... -- T8637 -- Length = 53 rows Note that using a different unit will result in different output units in the ``Observed`` and ``Ritz`` columns. There are several other optional parameters that you may also set. For instance you may set the ``energy_level_unit`` to any one of these values. :: 'R' 'Rydberg' 'rydberg' 'cm' 'cm-1' 'EV' 'eV' 'electronvolt' 'ev' 'invcm' Similarly you can set the ``output_order`` to any one of 'wavelength' or 'multiplet'. A final parameter you may also set is the ``wavelength_type`` to one of 'vacuum' or 'vac+air'. Here is an example with all these parameters. .. doctest-remote-data:: >>> from astroquery.nist import Nist >>> table = Nist.query(4000 * u.nm, 7000 * u.nm, 'H I', ... energy_level_unit='eV', output_order='wavelength', ... wavelength_type='vacuum') >>> print(table) Observed Ritz Transition Rel. ... Upper level Type TP Line -------- ----------- ----------- ----- ... ------------------- ---- ----- ----- -- 4020.871 2487.024 (200) ... 14 | | -- T8637 -- -- 4052.18664 2467.803411 -- ... 5d | 2D | 3/2 -- T8637 -- -- 4052.19376 2467.79907 -- ... 5p | 2P* | 3/2 -- T8637 -- -- 4052.22121 2467.78236 -- ... 5s | 2S | 1/2 -- T8637 -- -- 4052.23222 2467.77565 -- ... 5p | 2P* | 1/2 -- T8637 -- -- 4052.248747 2467.765585 -- ... 5f | 2F* | 5/2 -- T8637 -- -- 4052.24892 2467.765479 -- ... 5d | 2D | 5/2 -- T8637 -- -- 4052.26147 2467.75784 -- ... 5p | 2P* | 3/2 -- T8637 -- -- 4052.26174 2467.757676 -- ... 5d | 2D | 3/2 -- T8637 -- -- 4052.26738 2467.75424 -- ... 5g | 2G | 7/2 -- T8637 -- ... ... ... ... ... ... ... ... ... 5128.65 5128.662 1949.83 (450) ... 10 | | -- T8637 L7452 -- 5169.282 1934.5047 -- ... 19 | | -- T8637 -- -- 5263.685 1899.8096 -- ... 18 | | -- T8637 -- -- 5379.776 1858.8134 -- ... 17 | | -- T8637 -- -- 5525.19 1809.8925 (150) ... 16 | | -- T8637 -- -- 5711.464 1750.8646 (180) ... 15 | | -- T8637 -- -- 5908.22 1692.5572 (540) ... 9 | | -- T8637 -- -- 5956.845 1678.7409 (210) ... 14 | | -- T8637 -- -- 6291.918 1589.3405 (250) ... 13 | | -- T8637 -- -- 6771.993 1476.6701 (300) ... 12 | | -- T8637 -- -- 6946.756 1439.5208 -- ... 20 | | -- T8637 -- Length = 37 rows Reference/API ============= .. automodapi:: astroquery.nist :no-inheritance-diagram: