projected_size¶
- sbpy.units.projected_size(eph: sbpy.data.ephem.Ephem)[source]¶
Angular size and projected linear size equivalency.
Based on the tangent formula:
length = delta * tan(angle)
- Parameters
- eph
Quantity
, dict-like,sbpy.data.Ephem
Distance to the object as a quantity or the field
'delta'
.
- eph
- Returns
- eqivlist
List of equivalencies
Examples
>>> import astropy.units as u >>> import sbpy.units as sbu >>> (1 * u.arcsec).to('km', sbu.projected_size(1 * u.au)) ... <Quantity [725.27094381] km> >>> (725.27 * u.km).to('arcsec', sbu.projected_size(1 * u.au)) ... <Quantity [1.00] arcsec>