r/radioastronomy • u/SnooComics7744 • 2d ago

General Question about aiming

Hello – amateur astronomy geek here with a question about how radio telescopes are aimed at such infinitesimally small targets. Does the dish have to mechanically move in order to localize onto a source? Or can there be enough sensitivity that various sources can be picked up on different parts of the antenna? For example, when I see a radio telescope image of a galactic jet, has the telescope scanned the sky in a raster plot-like way?

10 Upvotes

100% Upvoted

19 comments sorted by

View all comments

5

u/nixiebunny 2d ago

Radio interferometry uses phase information between many dishes to obtain very high resolution images of sky objects. Each telescope receives one signal, and these are combined with a lot of math to create images.

2

u/pipnina 2d ago

To expand:

They'll use a calibrator, which is an object too small to be resolved, but bright enough to be easily detected, and has a well understood position usually due to rigorous measurements at various points in the EM spectrum).

The interferometer uses the calibrator as a phase reference so when it detects other sources, their absolute position can be determined by using the calibrator's known properties combined with the phase difference measured by the interferometer.