Astronomical Institute AS CR Academy of Sciences CR
Astronomical Institute,
Academy of Sciences of the Czech Republic
Stellar
Physics
Department

Ondrejov ThAr atlas - examples

See also KPNO ThAr atlas

The ranges of exposed spectra

At first, we present tables and graphs depicting the beginnings and ends of exposed spectra as they depend on grating angle. Thus one can fit and find another angle of grating to depict asked spectral regions.

For the first spectral order (red regions)

Grating angle Spectral order
Increments Degrees Beginning End
532135.788401.48869.9
543035.258197.28666.3
638230.626406.26878.6
645730.256263.56736.0
694327.885328.65801.4


and for the second spectral order (blue regions)

Grating angle Spectral order
Increments Degrees Beginning End
471238.754758.84991.1
504037.154459.94693.4
524236.174273.74507.7


One can see that grating angles in increments are in "anticorrelation" with the degrees (when increments are increasing, degrees are decreasing).

Examples of ThAr spectra exposed in Ondrejov, identification

First spectral order - red regions

Gaia region

O I region

He I region

H alpha region

N II region

Second spectral order - blue regions

H beta region

H gamma region

Fe II region

Mg II region

Region of high Balmer lines

We do not recommend to observe under 3800A (i.e. under the last presented region) because the efficiency of the CCD chip is falling down steeply around these wavelengths.