Passage of the Milky Way Plane
Joachim Köppen Kiel Dec 2024
Some brief explanations
This utility computes the sky position (Az, El) of a radio telescope from the observed times of the passages of the Milky Way
plane, which gives the strongest signal in the HI emission (in the line at 1420 MHz) during a 24 h scan of the sky by the
fixed telescope.
After making numerical entries, hit the Enter key to update the diagram.
In the diagram, the green curve shows for each point on the galactic equator the relation between its galactic longitude
and the declination.
The pair of tick black lines indicates the position of the local horizon: for a telescope on the
northern hemisphere, declinations below these lines are not accessible. Likewise, a telescope on the southern hemisphere
cannot view any objects with declinations above the line pair.
The maganta line marks the declination at which telescope looks, when the time between the two passages of the Milky Way
Plane, as specified by the user, is equal to the corresponding time interval at this declination.
If the predicted elevation of the telescope turns out to be negative, click the 'swap times' button: This lets us
take the correct time interval.
The accuracy of this approach is at best ±1°.
Observer's position
longitude [W]
latitude [N]
Date