Coordinates
Joachim Köppen DF3GJ ... Kiel, July 2016
This tool is converts between the various coordinates of sky objects. Green fields are input items. Clicking on a text field such as Az or El allows input of these coordinates. RightAscension comes in two formats: decimal hours and degrees. Click the compute button or the Enter key to recompute.
VHEL corrects the radial velocity measured on the Earth to the heliocentric radial velocity: vhel = vrad - VHEL. Likewise, VLSR corrects to the radial velocity with respect to the Local Standard of Rest (LSR), which is the reference frame which represents the mean motion of the stars in the solar neighborhood in the Milky Way galaxy: vLSR = vrad - VLSR. fcenter is the observed frequency of the HI 1420 MHz line when observed along this line of sight in our Galaxy.