When I've been to Astronomy-nights for the public at the local observatory, they always used green lasers to point things out. Why is there such a preference for green lasers? What's wrong with red ...
I couldn't find on the web how to get the velocity dispersion and velocity maps of galaxies from the 3D data cube that I get from the integral field spectrograph.
With about all visible stars catalogued, measured and photographed it seems that chapter is closed. I realize currently while amateur astronomy is big on cataloguing all asteroids in the Solar System, ...
How do professional astronomers measure and describe (ambient) observation conditions? I know smog, light contamination from the city lights, fog, clouds, rain/snow, humidity etc all contribute ...